CHARACTERISTICS OF ORAL CONDITION AMONG WORKERS IN THE FIELD OF RADIATION
By
Radwa Abd El Basset Ibrahim Sallam B.Sc. Faculty of Dental Medicine – Cairo University , 1993 Master of Orthodontics – Faculty of Dental Medicine, Alex. University, 2003
A thesis submitted in Partial Fulfillment Of The Requirement for the Doctor of Philosophy Degree In Environmental Science
Department of Environmental Medical Science Institute of Environmental Studies and Research Ain Shams University
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APPROVAL SHEET CHARACTERISTICS OF ORAL CONDITION AMONG WORKERS IN THE FIELD OF RADIATION
By Radwa Abd El Basset Ibrahim Sallam B.Sc. Faculty of Dental Medicine – Cairo University , 1993 Master of Orthodontics – Faculty of Dental Medicine, Alex. University, 2003
This thesis Towards a Doctor of Philosophy Degree in Environmental Science Has been Approved by:
Name Signature 1- Prof. Dr. Khaled Atef Abd El Ghaffar Prof & Head of Department of Oral Medicine Faculty of Dental Medicine Ain Shams University
2- Prof. Dr. Atef El Shaat Attia Prof. of Oral Medicine Faculty of Dental Medicine Cairo University
3- Prof. Dr. Mahmoud Serry El Bokhary Prof. & Head of Department of Environmental Medical Science Institute of Environmental Studies & Research Ain Shams University 4- Dr. Hala Ibrahim Awadalla Assistant Prof. in Department of Environmental Medical Science Institute of Environmental Studies & Research Ain Shams University
2012
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CHARACTERISTICS OF ORAL CONDITION AMONG WORKERS IN THE FIELD OF RADIATION
By
Radwa Abd El Basset Ibrahim Sallam B.Sc. Faculty of Dental Medicine – Cairo University , 1993 Master of Orthodontics – Faculty of Dental Medicine, Alex. University, 2003
A Thesis submitted in Partial Fulfillment Of The Requirement for the Doctor of Philosophy Degree In Environmental Science Department of Environmental Medical Science
Under The Supervision of:
1- Prof. Dr. Khaled Atef Abd El Ghaffar Prof & Head of Department of Oral Medicine Faculty of Dental Medicine Ain Shams University 2- Prof. Dr. Abd El Monem Bashandy Prof. of Microbiology National Center of Radiation Research & Technology 3- Dr. Hala Ibrahim Awadalla Lecturer. in Department of Environmental Medical Science Institute of Environmental Studies & Research Ain Shams University 4- Dr. Mohamed Gaber Haggag Lecturer of Oral Medicine National Center of Radiation Research & Technolo
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Acknowledgement
First of all, I would like to thank ALLAH for his great mercy and virtues that enabled me to complete this work I would like to express my sincerest gratitude and grateful appreciation to Professor Dr. KhaledAtef Abdel Ghaffar, Head of Oral Medicine and Periodontology Department, Ain Shams Univeristy for his precious time, his patience, his excellent supervision and valuable advice. I am deeply indebted to Professor Dr Abdel Moenem Bashandi Professor of Microbiology, National Center of Radiation Research and Technology (NCRRT) for his unlimited generous efforts, valuable suggestions, constructive criticism and fatherly advice. My deep thanks for Dr Hala Awadalla, Assistant Professor of Medical Science Institute of Environmental Studies and Research, Ain Shams University for her sincere co-operation and continuous support and consistent supervision My special thanks and great respect for Dr Mohmed Haggag, Lecturer of Dental Medicine, National Center of Radiation Research and Technology (NCRRT) for his kind help and fruitful co-operation in this thesis.
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DEDICATION
To My Parents who always loved and supported me unconditionally
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Abstract
This study was designed to investigate the characteristics of oral conditions of the workers in radiation field. The study was carried out on male subjects with age ranging from 25- 45 years working in National Center for Radiation Research and Technology (NCRRT) under protective measures and subjected to low dose long term of ionizing radiation. The subjects were divided to 4 groups the first three groups represent the study groups and includes subjects working in radiation field and a fourth group which is the control group and includes subjects working away from radiation field). Study groups were divided according to duration of working time into: First group including 20 subjects working for at least 10 years, Second group including 20 subjects working from 5-10 years and Third group including subjects working for at least 5 years. The investigation in both Study and Control groups was made via, immunological assessment by determination of the level of secretory immunoglobulin A (SIgA), microbiological assessment via detection of aerobic, anaerobic bacteria and Candida albicans and by dental assessment through determination of dental indices(Decayed Missed –Filled (DMF) index, periodontal index and Plague index). The results of this study reported lower level of SIgA in study groups compared to controls . Significant presence of Aggrebacter- actinomycetemcomitans, Fusobacterium and Bacteriod Forythus in study groups. Significant difference between study groups and controls regarding DMF index, Periodontal index and Plaque index in addition to, negative correlation between SIgA and the dental indices
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LIST OF CONTENTS
Title Page No.
Introduction ...... 1
Aim of the study ...... 16
Review of literature ...... 17
Hazardous effects of radiation ...... 31
Saliva ...... 55
Oral microbiota ...... 72
Subjects and methods ...... 92
Results ...... 106
Discussion ...... 132
Summary and Conclusions ...... 145
Recommendations ...... 150
References ...... 152
Arabic summary ...... ––––
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LIST OF TABLES
Table No. Title Page
Table (1): Collective Dose Equivalent for NCRRT Radiation Workers during 2005 – 2010 ...... 95 Table (2): Comparison between groups concerning Aggregatibacter actinomycetemcomitans ...... 115 Table (3): Comparison between groups concerning Fusobacterium ...... 116 Table (4): Comparison between the four groups concerning Bacteriod ...... 116 Table (5): Comparison between groups concerning Streptococcusmutans ...... 118 Table (6): Comparison between groups concerning Staphyloccocus auries ...... 119 Table (7): Comparison between groups concerning Pseudomanas aerogonsa ...... 119 Table (8): Comparison between groups concerning E.coli ...... 120 Table (9): Comparison between groups concerning Candida albicans ...... 120 Table (10): Comparisons and Significance of different types of Bacteria and Candida albicans ...... 121 Table (11): Comparison between groups concerning Dental Indices using Anova Test ...... 124 Table (12): Correlations between DMF, Plaque index, periodontal index and Secretary IgA ...... 128 Table (13): Comparison between the first group and the fourth group ...... 129
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Table (14): Comparison between the Second group and Fourth group ...... 129 LIST OF TABLES (Cont….)
Table No. Title Page
Table (15): Comparison between Third group and Fourth group ...... 130 Table (16): Comparison between the First group and the Third group ...... 131 Table (17): Comparison between the Second group and the Third group ...... 131
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LIST OF FIGURES
Figure No. Title Page
Figure (1): Electromagnetic Spectrum ...... 19 Figure (2): Mean distribution of occupational workers with annual dose interval during 2010...... 96 Figure (3): Colonies of Aggregatibacter actinmycetem- comitans on Brain Heart Infusion supplemented with 5% sheep blood and 5% serum...... 107 Figure (4): Colonies of Fusobacterium on TSA supplementd with 5% sheep blood and5% serum...... 108 Figure (5): Colonies of Bacteroid forythus on Brucella agar supplemented with8% sheep blood and 5% serum...... 109 Figure (6): Colonies of Streptococcus mutans on MacConkey agar ...... 110 Figure (7): Colonies of Staphaphylococcus aureus on Blood agar ...... 111 Figure (8): Colonies of Pseudomanas aerogonsa ...... 112 Figure (9): Colonies of E. coli on (Luria Bertani agar) ...... 113 Figure (10): Colonies of Candidaalbicans on MacConkey agar ...... 114 Figure (11): Distribution of Aggregatibacteractinomycetem comitans among studiedgroups ...... 117 Figure (12): Distribution of Fusiobacterium among studied groups ...... 117 Figure (13): Distribution of Bacteriod among studied groups ...... 118 Figure (14): Distribution of Streptococcus mutans among studied groups...... 121
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LIST OF FIGURES (Cont…)
Figure No. Title Page
Figure (15): Distribution of Staphlococcus auries among studied groups...... 122 Figure (16): Distribution of Pseudomonasaeruginosa among studied groups...... 122 Figure (17): Distribution of E.coli among studied groups...... 123 Figure (18): Distribution of Candidaalbicans among studied groups...... 123 Figure (19): Relation between the four groups concerning the DMF score...... 125 Figure (20): Relation between the four groups and concerning the periodontalindex...... 125 Figure (21): Relation between the four groups concerning of the Plaque index...... 126 Figure (22): Relation between the four groups concerning secretary IgA...... 127
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INTRODUCTION
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INTRODUCTION
e live in radioactive world. Radiation is permanently Wpresent through out the environment whether from natural and / or artificial sources.
Natural sources contribute about four to five times as much as artificial ones; they could be in the form of cosmic radiation, rocks, natural radium, uranium and thorium. Artificial source could be from medical radiation sources, industrial uses and nuclear technologies. Ionizing radiation negative biological effect on living organisms depends on dose of radiation and duration of exposure.
Prolonged exposure to radiation particularly ionizing radiation has adverse effects on human health and immunity leading to systemic diseases.
Different tissues of the body respond differently to radiation, due to varying degrees of radio sensitivity. When an adult subject is irradiated over the entire body, various syndromes are manifested depending on the dose applied. The effects of radiation are characterized by the survival time the species and various stages of acute syndromes following the total body irradiation. These effects are deterministic types and have a threshold dose.
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The long term or late effects of radiation cause various syndromes long after the radiation exposure. These may appear after acute radiation syndrome subside following exposure to a single large dose or after exposure to many smaller doses over a period. The late effects may be somatic or genetic, depending on the respective cells involved. Somatic effects are seen in the form of carcinogenesis, life shortening, cataract genesis, and embryologic damage. On the other hand, genetic effects result in abnormalities in the offspring.
Dental diseases don’t differ from any other diseases as the environmental factors may moderate dental diseases from day to day (Van Haute and Green, 1974).
Occupational disease of hard and soft oral structures is due to direct action of the occupational causative agent on the workers oral tissue, which is affected as part of systemic disturbance (Blatt, 1976).
Throughout the years, most of the studies focused on the damaging effects of high levels of radiation on dental, oral structures and salivary glands and its oral complications which is manifested clinically.
Oral complications of radiotherapy in the head and neck region are the result of the deleterious effects of radiation on, salivary glands, oral mucosa, bone, dentition, masticatory musculature, and temperomandibular joints. The clinical
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consequences of radiotherapy include mucositis, hyposalivation, taste loss, osteoradionecrosis, radiation caries, and trismus. Mucositis and taste loss are reversible consequences that usually subside early post irradiation, while hyposalivation is normally irreversible. Furthermore, the risk of developing radiation caries and osteo-radionecrosis is a life long threat.
Exposure to low doses of ionizing radiation is a fact of life in certain occupational settings, long-term effects of low-dose exposures may be real and should be given serious consideration however, the effects of low levels of radiation are more difficult to determine because the deterministic effects do not occur at these levels. Consequently, the risk values at occupational levels are estimates based on risk factors measured at high doses and the risks of low dose radiation effects are not directly measurable in populations of exposed workers (Bethesda,1993, Godekmerdan et al., 2004).
Accordingly, further studies should be conducted to determine the risk factors of the exposure of low doses of radiation for long durations.
15 Aim of the Study
AIM OF THE STUDY
ssessment of orodental changes due to exposure to Aionizing radiation in individuals working in the field of radiation by determination of:
1- Secretary IgA levels.
2- Changes in the oral microflora.
3- Dental changes which may be induced on the oral structures.
16 Review of Literature
REVIEW OF LITERATURE
Basic Background of Radiation
adiation refers to complete process in which energy is Remitted by one body or source, transmitted through an intervening medium or space and absorbed by another body.
The energy transfer occurs in the form of subatomic particles or electromagnetic waves (Walter and Miller, 1969).
I) Particulate or corpuscular radiation
It is the form of rapidly moving charged or neutral subatomic particles as Alpha, Beta and Neutrons particles
Alpha particle (α): is a positively charged helium nucleus emitted by a larger unstable nucleus and composed of 2 protons and 2 neutrons.It is a relatively massive particle, but it only has a short range in air of 1-2 cm and can be absorbed completely by paper or skin. Alpha radiation can however, be hazardous if it enters the body by inhalation or ingestion of α emitting materials, because large radiation exposures can result in nearby tissues, such as the lining cells of the lung or stomach.
Beta particle (β): is fundamentally an electron with the same mass and charge. It is different from electron only in the fact that it originates from the nucleus. There are two forms:beta -ve (β-) (negatron) and beta +ve (β+) (positron). Both negatron and positron have the same mass and also the same 17 Review of Literature charge but of opposite sign. Beta radiation (β) is emitted by an unstable nucleus. Beta particles are much smaller than alpha particles and can penetrate further into material or tissue. Beta radiation can be absorbed completely by sheets of plastic, glass, or metal. It does not normally penetrate beyond the top layer of skin. However, large exposures to high-energy beta emitters can cause skin burns. Such Beta emitters can also be hazardous when emitting materials a re, inhaled or ingested.
Neutron radiation (n): neutron particles are emitted by an unstable nucleus, in particular during atomic fission and nuclear fusion. Apart from being a component it cosmic rays, neutrons are usually produced artificially Because they are electrically neutral particles, neutrons can be very penetrating and when they interact with matter or tissue, they cause the emission of beta and gamma radiation . Neutron radiation therefore requires special shielding with low atomic number materials to reduce exposures (Al Naggar, 2009).
II) Electromagnetic energy
These radiations are the form of energy in motion that does not have mass and charge and can propagate as either waves or discrete packets of energy, called photons or quanta these radiations travel with velocity of light. Various Examples of electromagnetic radiations include radio waves, visible light, heat waves and so forth.
18 Review of Literature
The energy of electromagnetic radiation is given by
E = hv = h is Planck constant given as 6.625 x 10-27erg.s/cycle
V is the frequency in hertz, is the wave length in centimeters and c is the velocity of light in vaccum which is equal to 3 x10 10cm/s (Sopha, 2006).
This spectrum of radiation extends from gamma rays of extremely short wave length followed by x ray, ultraviolet (UV), visible light, infra-red, short and long radio waves.
Figure (1): Electromagnetic Spectrum
Ionizing Radiation
It is radiation that can knock electron off atoms causing them to be electrically charged or ionized.
Ionizing radiation when absorbed by material can change the atomic structure of the material by knocking out of atoms
19 Review of Literature
Gamma and x rays are known as ionizing radiation (WHO, 1997).
Non Ionizing radiation
Non ionizing radiation lacks the energy to facilitate the release of electrons from target tissues. It doesn't change atomic structure of the human body. Ultraviolet light (UV), visible light, infrared light, Micro waves and Radio frequency are non ionizing radiation (WHO, 1997).
Modes of Radiation Exposure
There are two modes of radiation exposures, namely External and Internal Exposure.
External Radiation Exposure
Occurs when the radiation source is outside the body, and the emitted radiation energy reaches the body and is absorbed by the body tissues according to the mechanisms of absorption of that particular radiation energy. The factor in this type of exposure is physical factors including type and energy of incident radiation, magnitude of exposure; and biological factors, essentially the density of the body tissues. External exposure depends greatly on source, body geometry; and may be localized, partial or whole body. The dosimetric considerations of external exposure are straight forward and are somewhat complicated in situation of complicate source -body geometry.
20 Review of Literature
Internal Radiation Exposure
Occurs when the radiation source in solid, liquid, or gaseous gains entry into the body by Inhalation, Ingestion, or Transcutaneous (through the skin). In this situation the radiation energy emitted from the source is absorbed to various distances according to the differential penetration of the energy and type of radiation released from the source, the factor controlling internal exposure are numerous, including amount and type of radioactive material, its chemical and physical properties, and degree of its incorporation in body tissues. The dosimetric considerations of internal exposure are certainly complicated including several chemical, physical and biological aspects of the radioactive material that gained entry into the body.
Direct and Indirect Action of Radiation:
Direct Action
Direct action of radiation entails simply the localized deposition of ionizing radiation energy by high-energy charged particle (electrons, protons, and Alpha particles...etc) within a specific molecular structure. This direct action of radiation involves the simple direct interaction between the radiation energy and a critical biological molecule, and this molecule becomes directly changed (ionized) into free radicals, which are highly reactive.
21 Review of Literature
Indirect Action:
Indirect action of radiation entails the formation of reactive species, by water radiolysis, and the diffusion of these species to the biological target molecule, acting as intermediates in the transfer of energy to the biological target molecule.
From the point of view of biological damage, it does not matter whether the critical molecule is damaged by direct action or indirect action. However, it seems most likely that much radio biologic damage is a consequence of indirect action, since the water content of cells and tissues approximates 70 - 75 percent water.
Excitation and Ionization Processes:
'The energy of ionizing radiation has the unique property of being absorbed in the physical bonds of atoms, and in the physicochemical bonds of molecules. These physical and physicochemical bonds have varying degrees of bond strength. The initial event of radiation energy absorption in a biological system is excitation of the physicochemical bond. With more radiation energy absorption in the bond, Ionization of the bond takes place. This ionization occurs when the radiation energy absorbed in the bond reaches the Ionization Potential of that particular bond (i.e. overcomes the binding energy of that bond).
22 Review of Literature
The excitation energy is eventually dissipated in the molecular environment, with very minimal or transient molecular alteration. It is essentially the process of ionization induces molecular alterations (Al Naggar, 2006).
The sequential stages of Radiation action:
In all biological systems, water is the most abundant molecule and radiation-induces splitting of the water molecule, the radiolysis of water is a primary event in the initiation of biological damage (Potten, 1985).
Induction of radiation injury has four phases:
The first phase (physical phase) is the shortest lasting about 10 second. During this phase, energy is deposited in the cell causing ionization and excitation of ions and molecules. The absorption of energy by a water molecule results in the ejection of an electron (e-) leaving a positively charged species. H2O+
+ - H2OH2O +e
The second phase (physicochemical phase) which lasts about 106 second the positive ion dissociates to yield a hydrogen ion, H and hydroxyl free radical OH - - H2O e H2O o - H2O H + OH
23 Review of Literature
The principal products of these two phases are hydrogen and hydroxyl ions and free radicals. Hydrogen and hydroxyl ions are normally present, the free radicals are very reactive species and may undergo many reactions, for example two (H) or (OH) radicals may combine to form hydrogen molecule and hydrogen peroxide (H2O2) which is a powerful oxidizing agent (Prasad, 1974).
H° + H° H2
OH° + OH°H2O2
The third phase (chemical phase) lasting few seconds, the free radicals react with organic molecules within the cell. Reactions with proteins and (DNA) of the cell nucleus may produce change in the secondary or tertiary structure of proteins, as a result of disruption of hydrogen bonds, or inter or intra-molecular cross-linking in the double stranded (DNA) molecules which may have particularly serious effects (Prasad, 1974).
The fourth phase (biological phase) during which the chemical changes are transformed into cellular changes. Three types of cellular changes may be recognized. These are early cell death, prevention or delay of cell division (mitosis) and the production of permanent inheritable changes which may be passed on daughter cells at mitosis. These changes may lead to other changes which affect the whole organism.
24 Review of Literature
This phase of development of radiation injury shows the longest and most variable time scale. Some effects may develop within a few hours while others for example cancer induction may take many years to be apparent.
Radiolysis of water:
The unique role of water in chemical and biological systems, the irradiation of pure water is of special interest. Early experiments have proved that the radiation-water molecules interaction results in the formation of hydrogen, oxygen and hydrogen peroxide. This reaction has been explained in terms of free radical reaction (Blackely, 1968).
Ionization and free radical formation:
Ionizing radiation is considered as particular form of radiation which produces ionization target molecules (Adams, 1968). The sequence of events induced by irradiating the biological system can be either direct or indirect. The direct effect of radiation on the cell is mainly concentrated on water molecules which represent 70-80% of the biological system, with the results of formation of charged ions.
These charged ions are unstable and decompose immediately, leading to free radicals (O H-) and H-.
The free radicals OH- and H- are highly reactive, unstable species. On the other hand, the direct effect on the biological organic molecules can be summarized as follows:
25 Review of Literature
Radiation RH RH+ + e-
Radiation RH R- + H+ Where R- is an organic free radical, and RH is the biological target molecule
The indirect effect of the ionizing radiation involves the production of aqueous free radical OH-and H+ and thus an interaction with the biological organic molecule. - - RH + OH →R + H2O
+ - RH + H → R + H2 The organic free radicals R may give rise to permanent damage.
Oxygen effect: The chemical products of the radiation ionization of water are the hydroxide radical (OH-) and me hydrated electron (e-) which has one reducing equivalent When biological molecules are present in water (oxidized or reduced') the)' may be attacked by the corresponding radicals
If oxygen is present in the irradiation medium, then an increased amount of damage might be expected to be produced through the following reaction ;
- 2- R +O2 → RO
26 Review of Literature
Where RO2-is an organic peroxyradical not easily repaired, thus, radiation damage is permanent. In certain parts of cells, a chain reaction may proceed which would generate more of the free radicals and so on....
Another damage process may involve the formation of hydrogen peroxide (H2O2) in the irradiated tissues. This reaction step starts when the oxygen originally present in the medium reacts with the aqueous free radical H+ . + - H +O2→ H2O 2- 2HO → H2O2 +O2
Hydrogen peroxide (H2O2) may also be formed in a similar manner from hydrogen electrons. H2O2is very toxic to biological structures and is a relatively stable product. (Blackely, 1968).
Effect of ionizing radiation on living organisms:
Blackely (1968) described the action of radiation, by its capacity of ionization and excitation, breaks up into fragments. Some of these fragments are charged and some uncharged, but all are highly reactive. These fragments may later react chemically with neighboring molecules and between themselves; this stage may last from fraction of a second to hours. These early reactions then give rise to further reactions in which very large molecules such as these of proteins, and metabolic pathways essential to the cell distributed. As a result,
27 Review of Literature processes leading to synthesis of essential cell constituents may be retarded or inhibited, finally the cell may die.
If radiation, effect is more localized to the nucleus, which is the most radiosensitive structure, damage to the chromosomes can occur which may be sufficiently severe to lead to death of the cell at its next division. Alternatively, lesser damage to the chromosomes or genes, which carry inherited characteristics of cells and organisms, may result in changes known as chromosome or gene mutations.
If the affected cells are germ cells in the gonads, these mutations can be passed on to the offspring. Cells undergoing mitosis are most sensitive to ionizing radiation and chromosome damage may induce malignant changes and genetic abnormalities (Evans, 1974).
Factors influencing cellular response to radiation:
Radiation produces both direct and indirect injurious effects on biologic systems- The relative contribution of each mechanism depends on the system involved and a variety of other factors such as the character of the radiation and die presence or absence of agents known to protect against the effects of radiation. The important factors that influence the radiosensitvity of mammalian cells can be divided into three groups physical, chemical and biological (Anderson, 1985).
28 Review of Literature
A- Physical factors:
The most important physical factors that affect the magnitude of biologic response to radiation are the character of the radiation quantity the total amount administrated and the time within which this dose was given.
El-Shakankery (1989) showed that the linear energy transfer (LET) is the term that describes the rate at which energy is lost from different types of radiation while traveling through matter. LET depends on the mass, the charge, and the velocity of the particle. A particle with a relatively large mass and charge but low velocity will in general exhibits a higher LET than a small non-charged particle with high velocity. X- ray and γ-rays were termed as low LET radiation, while a particles and neutrons as high LET radiation. Equal doses of radiation of different LETs do not produce the same biologic response.
Moreover, Anderson (1985) pointed out that dose rate also influences cell survival especially for low LET radiation. In case of low LET radiation, a greater total dose is required to produce the same effect when the radiation is either delivered in fractions of given continuously over a prolonged period of time.
B-Chemical factors:
Chemical factors are either radiation sensitizers which potentiate the effect of the ionizing radiation or radiation protectors which exert a protective effect.
29 Review of Literature
1-Radiation sensitizers: A true radio-sensitizer is one that increases the cell killing effect of a given dose of radiation. Oxygen has the most dramatic effects and is found to
Potentiate many of the effects of ionizing radiation. The oxygen effect is most pronounced with low LET radiation such as X and γ rays. Oxygen increases the production of free radicals by radiation. The oxygen effect is of special importance for the treatment of malignant tumors with ionizing radiation (Anderson, 1985).
2- Radiation protectors:
Radiation protectors serve against radiation induced cell injury. The best known examples are the sulfhydryl amines such as cysteine and - cystamine- When one of these is given prior to radiation; a larger dose is if necessary to produce the same response as when the compound was not administered (El-Shakankery, 1989).
3- Biologic factors:
The phase of the cell in the cell cycle at the time of irradiation has a great influence on the cellular response. In most tissue culture lines, the cells were more sensitive to radiation during G2 stage and mitosis, less sensitive during G1 stage and least sensitive towards the end of the S stage (El- Shakankery, 1989).
30 Review of Literature
HAZARDOUS EFFECTS OF RADIATION
Cell damage
ell death is a measure of extreme radiation damage. CTherefore, based on the degree of lethality induced by radiation, radiation damage can be classified into three categories;
(1) Lethal damage, which. cause, irreversible death.
(2) Sublethal damage (SLD), which normally repairs in hours and thus avoids cellular death. Unless followed by another sublethal damage.
(3) Potentially lethal dose (PLD), which can potentially kill the cell but can be modified to repair under specific physicochemical conditions. All these damages are relevant in clinical radiation therapy as to the effectiveness of treatment. Lethal damage is a definite end point in treatment. Whereas, SLD and PLD have variable effects in radiation therapy.
Stochastic and deterministic (non-stochastic) effects
The harmful effects of radiation may be classified into two general categories: stochastic and deterministic (previously called non-stochastic). The National Council on Radiation Protection and Measurements (NCRP) defines these effects as follows:
31 Review of Literature
A) Stochastic effect:
Is one in which the probability of occurrence increases with increasing dose but the severity in affected individuals does not depend on the dose (induction of cancer, radiation carcinogenesis and genetic effects). There is no threshold close for effects that are truly stochastic, because these effects arise in single cells and it is assumed that there is always some small probability of the event occurring even at very small doses.
The populations at risk are atomic energy workers, staff of medical radiation (diagnostic and therapeutic), mining workers and embryos of the above groups. These include hereditary, congenital and teratogenic genetic, cancer transformation, premature aging, cataract and infertility.
a) Congenital malformations and teratogenic effects: effects that may be produced in the developing embryo-fetus during intrauterine life, induced by exposure of the abdomino- pelvic region of the pregnant mother to radiation. The type and degree of malformation depends upon the magnitude of the radiation dose and more specifically on the stage of gestation at which radiation exposure took place. Teratogenesis is those effects expressed and
Permanently present in the organism. The origin of it must be genetic, congenital or induced.
32 Review of Literature
b) Genetic effects are produced by radiation induced injury to genetic material (DNA) in the cell. They are termed mutations which are defined as any permanent change in the chemical physical, functional or structural properties of the DNA molecule. Mutations are divided into gene mutation and chromosome aberrations.
c) Hereditary effects are effects that are transmitted to the progeny of parents who have developed radiation injury to the gonads. These effects may be expressed in the first generation or later.
d) Cancer transformation: may occur due to permanent change to the DNA molecule which is called initiation process. If clones of mutant cells are presented (due to inactivation of tumor suppressor genes) this stage is called promotion process. When the cell becomes committed to the malignant process, it is called the conversion stage.
e) Others: Premature Aging, Cataract and Infertility (Carton et al., 1974).
Deterministic effect:
A deterministic effect (tissue reaction) is one that increases in severity with increasing dose, usually above a threshold dose in affected individuals (organ dysfunction, fibrosis. lens opacification. blood changes and decrease in sperm count).
33 Review of Literature
These are events caused by damage lo populations of cells. Hence the presence of a threshold dose
Acute versus late tissue or organ effects:
An organ or tissue expresses response to radiation damage either as an acute effect or as a late (chronic) effect.
Acute effects manifest themselves soon after exposure to radiation and are characterized by inflammation, oedema, denudation of epithelia and haemopoietlic tissue, and haemorrhage are late effects are delayed. for example, fibrosis. atrophy, ulceration. stenosis or obstruction of the intestine, Late effects may be generic and caused by absorption of radiation directly in the target tissue, or consequential to acute damage in overlying tissues such as mucosa or the epidermis (Sopha, 2006).
Acute effects of total body irradiation
Different tissues of the body respond differently to radiation, due lo varying degrees of radio sensitivity. When an adult subject is irradiated over the entire body, various syndromes are manifested depending on the dose applied. The effects of radiation are characterized by the survival time the species and various stages of acute syndromes following the total body irradiation. These effects are deterministic types and have a threshold dose.
34 Review of Literature
Acute radiation syndromes appear in four stages: prodromal, latent. manifest illness, and recovery or death. Each stage is dose dependent and can last for a few minutes to weeks, A minimum of 200 to 300rad is required for all four stages lo be seen and cause death.
In the prodromal stage, major symptoms are nausea, vomiting, and diarrhea and they occur in the early phase, lasting for only a short period of time depending on the dose. A dose of 50 rad can induce nausea and vomiting. In the latent stage, biological damage slowly builds up without manifestation on of any syndromes, again lasting for hours to week, depending on the dose. During the manifest illness stage, radiation syndromes appear as a result of the damage to the organs involved after the latent period, and the subject becomes ill. In the last stage, the subject either recovers or dies.
There are three categories of syndromes in the manifest illness stage depending on the dose: hemopoietic or bone marrow, gastrointestinal Cardiovascular and central nervous system syndrome.
Haemopoitic "Bone Marrow syndrome, the threshold dose is about 2 Gy, manifested by pancytopenia, increase bone marrow proliferation and differentiation of stem cells. Gastro- intestinal syndrome, threshold dose is 4.5 Gy, manifested by gastro-enteritis, which leads to dehydration. Cardiovascular syndrome, the threshold dose is 6.5 Gy, manifested by
35 Review of Literature disturbance in micro flow, capillary fragility, petecial hemorrhages, myocardial ischemia, hypotension and cardiac shock. Central nervous system syndrome, the threshold dose is about 10 Gy, manifested by disturbance of the physiology and function of the cerebral cells leads to loss of reflexes, convulsions, coma, it has very bad prognosis. Associated syndromes include skin bums, depression of immune response and psychosomatic disturbance (Carton et al., 1994).
Long term effects of radiation
The long-term or late effects of radiation cause various syndromes long after the radiation exposure. These may appear after acute radiation syndromes subside following exposure to a single large dose or after exposure to many smaller doses over a period. The late effects may be somatic or genetic, depending on the respective cells involved. Somatic effects are seen in the form of carcinogenesis, life-shortening, cataract genesis, and embryo-logic damage. On the other hand, genetic effects result in abnormalities in the offspring.
Somatic effects
Somatic effects are harm that exposed individuals suffer during their lifetime, such as radiation induced cancers (carcinogenesis), sterility, opacification of the eye lens and life shortening. Carcinogenesis expresses itself as a late somatic effect in the form of acute or chronic myeloid leukaemia or
36 Review of Literature some solid tumours, for example in the skin, bone, lung. thyroid or breast.
Genetic Effects
Ionizing radiations can cause changes in the DNA structure, which ultimately are expressed in gene mutations, through the affected germ cells, these mutations propagate to future generations. Genetic effects are not expressed in the individual, whose germ cells have been affected by radiation, but arc expressed in future generations, Genetic effects appear as Down syndrome, achondroplasia, retinoblastoma, cystic fibrosis, sickle cell anemia, Tay-Sachs disease, and other chromosome disorders (Sopha, 2006).
Oral complications of radiation
Vissink et al. (2003) reported that, oral complications of radiotherapy in the head and neck region are the result of the deleterious effects of radiation on salivary glands, oral mucosa, bone, dentition, masticatory musculature, and temporo- mandibular joints. The clinical consequences of radiotherapy include mucositis, hyposalivation, taste loss, osteoradio- necrosis, radiation caries, and trismus. Mucositis and taste loss are reversible consequences that usually subside early post- irradiation, while hyposalivation is normally irreversible. Furthermore, the risk of developing radiation caries and osteoradionecrosis is a life-long threat.
37 Review of Literature
Kliebassa et al. (2006) concluded that when oral cavity and salivary glands are exposed to high doses of radiation,clinical consequences including irreversible consequence as hyposalivation and reversible consequences as mucositis and taste loss in addition to trismus, osteoradionecrosis and increased risk of rampiant caries.
Effect of radiation on salivary glands
The effects of radiation upon the salivary gland have been known for over ninety years having been first described in the human in 1911 (Bergonine, 1911). Ionizing radiation that includes the salivary glands results in acinar damage and cell death and affects the vascular elements of the glands with subsequent fibrosis of the salivary glands (Rankin et al., 2008).
The serous cells of salivary glands (mainly parotid glands) are relatively sensitive to ionizing radiation, whereas the mucous cells are relatively resistant. The early effects of radiotherapy result from interphase cell death of salivary serous cells, whereas late effects are determined by the ability to repopulate surviving stem cells (Someya et al., 2003).
In the human, the parotid gland is more radiosensitive when compared to the submandibular gland (Kashiima et al., 1965 and Baum et al., 1985).
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Various studies have noted over a 50% reduction in parotid gland function within a few days after exposure of the head and neck region to low doses of irradiation (Nagler, 2002).
The high sensitivity of the parotid gland has been suggested to be due to the predominance of serous cells in this gland as these epithelial cells appear to be the most radiosensitive (Kashiima et al., 1965 and Baum et al., 1985).
When the salivary glands are irradiated, many patients observe a decrease in production of saliva and an increase in its viscosity within the first week of radiotherapy (Burlage et al.,2001).
A high dose on the salivary glands results in a reduction of salivary output and a change in its composition. This in turn may lead to xerostomia which is cited by patients as a major cause of decreased quality of life (Harrison et al., 1997and Eisbruch et al., 2003).
Cooper et al. (1995) found that irradiated salivary tissues degenerates after a relatively small dose leading to markedly diminished salivary output which promote dental decay and affect the integrity of the mandible.
Lacatusu et al. (1996) stated that the irradiant cervicofacial therapy produces numerous complications which the repose and the buffering capacity of saliva and increase of salivary viscosity and the total quantity of proteins.
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Dawes and Oduim (2004) deduced that the mean salivary flow rate was lower in irradiated group compared to controls however the mean residual volumes were not significantly different and suggested that people who reported dry mouth have only localized areas of dryness notably the hard palate where the salivary fluid is thin and subjected to absorption or evaporation because of mouth breathing
Zheng et al. (2004) concluded that salivary gland is a highly radiosensitive organ and that gamma radiation is a risk factor for malignant and begnin salivary glands tumours. Ionizing radiation that includes the salivary glands results in acinar damage and cell death and affects the vascular elements of the glands with subsequent fibrosis of the salivary glands. Decreased salivary flow has been reported at doses of 10 Gy, while permanent hyposalivation may occur at doses greater than 25 Gy. When salivary production is compromised most individuals experience the sensation of a dry mouth, which is termed xerostomia.
Rankin et al. (2008) stated that, Loss of salivary function leads to a plethora of adverse sequelae, including: Alteration/reduction in taste function, difficulty with chewing, bolus preparation and swallowing, oesophageal dysfunction, including chronic oesophagitis, nutritional compromises, higher frequency of intolerance to oral medications and oral care products (lack of buffering), increased incidence of local/regional infection (glossitis, candidiasis, dental caries, 40 Review of Literature halitosis, bacterial sialadenitis), loss of oral buffering capacity, reduction in remineralizing capacity leading to dental sensitivity and markedly increased susceptibility to dental caries results in rampant caries involving teeth both within and outside of the fields of radiation., rampant caries can result in an increased risk of osteoradionecrosis, decreased resistance to loss of tooth structure due to attrition, abrasion and erosion (corrosion). Increased susceptibility to mucosal injury and Inability to wear dental prosthesis. It can also become an emotional challenge with the possible result of withdrawal and clinical depression.
Furthermore, such patients suffer from increased oral infections, difficulty in speaking, difficulty in swallowing food, and problems with digestion (Kashiima et al., 1965 and Baum et al., 1985).
Grundmann et al. (2010) reported that, a reduction of saliva flow rates by 50-60% with accompanying changes in saliva composition ensues during the first week of continued radiation therapy which has been associated with a loss of acinar cells and glandular shrinkage Serous acinar cells of the parotid gland are the main contributor of protein and water to the composition of saliva and that The treatment of head and neck cancer commonly involves fractionated radiation therapy which results insignificant side effects including xerostomia, dysphagia, and increased infection rate in most of the patients.
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Tolentino et al. (2011) stated that, the extent of radiation induced salivary dysfunction depends on the dose of radiation, the volume of irradiated gland the nature of salivary glands irradiated, the increased susceptibility to oral infections and dental caries and added that radiation therapy also changes the composition of saliva increasing its viscosity, reducing its buffering capacity altering its concentration of electrolytes and changing its non immune and immune antibacterial systems.
Effect of radiation dose on Salivary gland
Andrews and Griffiths (2001) found that Fractionated course of 1 Gy single dose is accompanied by clinical enlargement, pain and tenderness of the affected gland and that salivary gland damage frequently results in permanent hypo salivation after a radiation dose exceeding 40 Gy.
Someya et al. (2003) observed that when salivary glands are irradiated with doses less than 50Gy, gradual recovery occurs, whereas there was no significant recovery with doses more than 58Gy.
Jallema et al. (2005) reported that xerstomia is reversible depending on mean parotid and mean submandibular dose and no association was found with oral cavity dose however, considering sticky saliva there was an association after 6-12 months with mean submandibular dose.
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Effect of radiation on mucous membrane
Mucositis
Oral mucositis is defined as an injury of the oral mucosa in cancer patients, either induced by irradiation of patients who have head and neck cancer, or due to chemotherapy. This has debilitating and painful side effects and adversely affects the nutritional status of the patient. Mucositis is associated with an increase in the number of systemic diseases (Stokman et al., 2006).
According to WHO (1997), the two most commonly used scales include those developed by the National Cancer Institute and the World Health Organization.
National Cancer Institute (NCI) Scale: Grade 0 None Grade 1 Painless ulcers, erythema, or mild soreness in the absence of ulcers Grade 2 Painful erythema, edema, or ulcers but eating or swallowing possible Grade 3 Painful erythema, edema, or ulcers requiring IV hydration Grade 4 Severe ulceration requiring parenteral or enteral nutritional support or prophylactic intubation Grade 5 Death related to toxicity
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WHO Grading Scale: Grade 0 None Grade 1 Soreness / erythema, no ulceration Grade 2 Erythema, ulcers. Patients can swallow solid diet Grade 3 Ulcers, extensive erythema. Patients cannot swallow solid diet Grade 4 Oral mucositis to the extent that alimentation is not possible
Sonis et al. (2004) found that, radiotherapy causes a reduction in the rapidly dividing stem cells in the basal epithelial layer of the mucosa, preventing regeneration and affecting the integrity of the epithelium. At the molecular level, mucositis is a multi-stage process, initiated by mucosal injury
Sonis (2004) observed that, the first sign is inflammation and erythema of the mucosa within the treatment field. This is followed by production of a white pseudo membrane of fibrin, which eventually becomes confluent and covers the entire treatment field. Ultimately ulceration and breakdown of the mucosal barrier occurs, allowing the possible entry of pathogenic organisms. Bacterial colonization causes further production of cytokines thereby perpetuating the whole process.
Stokman et al. (2006) reported that, in a conventional radiotherapy scheme of fractionation, a first mucosal reaction in the form of mucosal hyperkeratinization can be observed, as a 44 Review of Literature white discoloration, after a cumulative radiation dose of 10-20 Gy but since, this stage is often overlooked or cannot be objectively diagnosed therefore, a deepening erythema is clinically considered to be the first sign and is usually visible after 20 Gy cumulative dosage. Thereafter, ulcerations can occur which are often covered with a pseudo membranous layer will develop after about 30 Gy, usually after 3 weeks of radiotherapy. After completion of the radiotherapy, the mucositis will decline after 2 to 6 weeks.
Rankin et al. (2008) reported that, mucositis is marked by inflammation and ulceration of the mucosal lining of the mouth, pharynx, esophagus and GI tract due to the direct cytotoxic effects on the epithelial cells and may be exacerbated by secondary infection with bacteria, fungi and viruses
Tahri et al. (2008) found a direct relationship between increase in radiation dose, irritation of oral mucosa, ulcer development and mucositis was observed but there was no significant relationship between NUG (necrotising ulcerative gingivitis) and radiation dosage. Periodontal index (PI), gingival index (GI) and papillary bleeding index (PBI) were increased, but due to limited time of study (6–7 weeks), no change in gingival recession was observed. Plaque index (PLI) decreased during treatment process because of oral hygiene instructions.
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Tolentino et al. (2010) reported that, mucosal damage occurs because of decreased cell renewal in the epithelium, which causes mucosal atrophy and ulceration and when the irradiation field involves the pharyngeal mucosa, it may produce difficulties in swallowing and speech and added that, clinically, mucositis is characterized by inflammation, erythema, mucosal atrophy, exulceration and ulceration of the oral mucosa with or without pseudomembranes.
Osteoradionecrosis
Rankin et al. (2008) stated that, Osteoradionecrosis is a complex process chiefly related to small blood vessel changes that result in an impaired capacity for the bone to heal and that it is a late side effect and its risk increases over time. . Although it can occur after lower doses, it is most commonly associated with radiation doses of >60 Gy.
Tolentino et al. (2011) reported that, one of the most severe adverse effects of radiotherapy is osteoradionecrosis, an inflammatory condition resultant of the bone ionizing radiation. This radiation results in irreversible damages to the osteocytes and the micro vascular system, with a progressive decrease of the micro vascularization. The tissue becomes hypo vascular, hypo cellular and hypoxic. All these features avoid the bone healing, and it can proceed to a necrosis with or without infection. These changes in bone result from injury to the remodeling system (osteocytes, osteoblasts and osteoclasts),
46 Review of Literature causing atrophy, osteoradionecrosis and pathological fractures. Tooth extraction and dental disease in irradiated regions have long been recognized as major risk factors for the development of osteoradionecrosis. The mandible is much more susceptible to osteoradionecrosis than the maxilla, because its vascularization is poor and bone density is high. This adverse effect usually occurs within one year of therapy. Radiologic features include ill-defined cortical destruction with or without sequestration Furthermore, Clinical manifestations of osteoradionecrosis may include pain, or facial fistulas, exposed necrotic bone, pathologic fracture .
Radiation caries
Lacatusu et al. (1996) observed that the irradiant cervicofacial therapy produces rampiant caries were found in the cervical zone, inscial edges and cusp zones
Andrews and Griffith (2001) reported that radiation caries has clinically distinctive pattern, smooth surfaces normally resistant to decay are the first affected caries development and progression are rapid and extensive tooth destruction may develop in a weeks.
Rankin et al. (2008) stated that Radiation-induced atrophy of salivary gland tissue leads to a decrease in quality and quantity of saliva, reducing the patient’s normal antimicrobial and remineralizing capacity which creates a higher risk for infection.
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Tolentino et al. (2011) reported that Radiation caries is not caused directly by irradiation, but results from the sequelae of xerostomia: decrease of pH, reduced buffering capacity, and increased viscosity. Clinically it has a rampant form, and tends to spread to all dental surfaces, changing their translucency and color. The carious process can cause increased friability and the breakdown of teeth. The most common type is widespread superficial lesions attacking buccal, occlusal, incisal and palatal surfaces.
Trismus
An oral opening lower than 20 mm can be considered as trismus, normal mouth opening is about 40-45 mm (Okeson, 1998).
Andrews and Griffith (2001) stated that when TM joint and muscles of mastication are exposed to radiation, the frequency and the severity of trismus is unpredictable ,development and maximum opening can be reduced to the point that mastication and oral intake of food are comprised.
Rankin et al. (2008) found that contraction of the masticatory muscles and TMJ capsule, usually occurring 3-6 months after radiation therapy, occurs with unpredictable frequency and severity and is accentuated by some surgical resections and higher radiation dosing to the pterygoid regions.
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Tolentino et al. (2011) reported that the mechanisms by which mandibular hypomobility due to the radiotherapy develops, and the factors which determine speed of onset, severity, and extent, are poorly understood. Its development is thought to progress in three phases: an initial nonspecific inflammatory phase, a fibrotic cellular phase, and a matrix densification and remodeling phase 3. It is generally viewed to be the result of fibrosis leading to a loss of flexibility and extension. Usually temporomandibular joint hypo-mobility is regarded as a late effect of high radiation dose.
Loss of periodontal attachment
Increased tooth loss and greater periodontal attachment loss over time is seen in teeth included in high-dose radiation fields (Andrews and Griffith, 2001).
Fungal Infections
Candidal infections of the oral mucosa are common in patients undergoing radiation therapy and can cause a burning or scalded sensation, distort taste and interfere with swallowing. However in many patients no symptoms are reported, so thorough oral examination is imperative to detect these infections (Andrews and Griffith, 2001).
Craniofacial disturbances
The craniofacial disturbances are those that shall occur when radiation therapy is performed in children if it is
49 Review of Literature performed in earlier stages, when teeth are still being formed. Abnormally small teeth (microdontia), short or blunted roots, small crowns, malocclusion, incomplete calcification, enlarged pulp chambers (taurodontism), premature closure of apices and delayed or arrested development of teeth have been reported these changes in the primary teeth can cause significant malocclusion and may adversely affect facial development.
Children undergoing radiation therapy may experience abnormalities in the growth and maturation of craniofacial skeletal structures .Craniofacial and dental abnormalities can cause severe cosmetic or functional sequelae, necessitating surgical or orthodontic intervention (Andrews and Griffith, 2001).
Nutritional Deficiency
Nutritional deficiencies occur secondarily as a result of mucositis, xerostomia, hypogeusia and loss of appetite that can make eating painful. Symptoms include rapid weight loss, dehydration, stomatitis secondary oral infections such as candidiasis (Andrews and Griffith, 2001).
Effect of Radiation on Oral Microflora
Abu shara et al. (1993) recorded the increase of Coagulase positive Streptoococcus mutans, Candida albicans, and Peudomonas aeruginosa in oral microflora after radiation exposure.
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Lacatusu et al. (1996) deduced that the microbial flora is modified after radiation exposure with increased level of Streptococcus mutans and Lactobacillus species.
Leung et al. (1998) investigated the sub gingival plaque microorganisms of shallow pockets (≤5 mm) in subjects who previously received irradiation in the head and neck region for treatment of nasopharyngeal carcinoma. The findings appear to suggest that the major components of the sub gingival micro flora of shallow sites in previously head-and neck-irradiated individuals are similar to that of gingivitis sites in the normal population although they may contain bacterial or fungal species uncommon in normal subjects Under the microscope, the micro flora was found to be a complex mixture comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes. Low level of fungi was observed and mycelia were occasionally detected. The predominant cultivable microflora comprised several species of facultative and obligate anaerobic bacteria:
Gemella, Peptostreptococcus, Staphylococus, Stomatococcus Streptococcus, Actinomyces, Eubacterium, Lactobacillus, Propionibacterium, Neisseria, Veillonella, Bacteroides, Campylobacter, Capnocytophaga, Fusobacterium, Kingella, Porphyromonas and Prevotella species.
Leung et al. (2000) found that radiation induced xerostomia seems to favors intraoral colonization of Candida
51 Review of Literature species particularly Candida albicans which undergo temporal modifications phenotypically and genotypically that enhance its survival in the oral cavity particularly when saliva defense is impaired.
Leung et al. (2001) found that radiation induced xerostomia seems to favors intraoral colonization of aerobic and facultatively anaerobic gram –ve rods and cocci which included Acinebacter, Neisseria, Citrobacter, Flavimonas, Pseudomonas, Chryseomonas, Enterobacter, Esherichia, Klebsiella, Flvobacterium and Weeksella species.
Andrews and Griffiths (2001) noted significant increase in numbers of Streptococcus mutans and Lactobacillus species at the expense of Streptococcus sangius. Furthermore, increase of Neisseria, Fusobacterium and Actinomomyces population.
Tong et al. (2003) observed that Streptococcus mitins and Streptococcus salivarius are the predominant non mutans streptococci in the high caries risk oral flora.
Belazi et al. (2004) assessed oral pseudo membranous candidasis and mucosititis in patients receiving a total dose of 39-40 Gy radiotherapy of head and neck.
Hofer et al. (2004) stated that irradiation induced salivary glands hypofunction is associated with a shift in the micro flora increasing the risk of rampiant caries and oral infections as candidasis
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Muthu et al. (2004) performed a full bacteriological analysis to determine the changes in oral flora after exposure to an external beam of radiation and found that there was a significant decrease in Hemolytic Streptococci and Neisseria, however there was a significant increase in B proteins and Candida albicans.
Llena et al. (2007) and Jham et al. (2007) reported that reduction of salivary flow in patients subjected to head and neck irradiation induces changes in the microflora and results in frequent presence of Candida species together with a shift towards non albicans species.
Almstahl et al. (2008) found Candida albicans in one or more sites in 54% of the radiation treated (RT) subjects and in 15% of the controls. In three RT subjects, Candida albicans was found at all four sites analyzed. An unexpected finding was that enterococci were found in all RT subjects and in high number in 38%. None of the controls harboured enterococci. In supragingival plaque, Lactobacillus spp. was detected in 92% of the RT subjects and the number and proportion of Lactobacillus spp. were extremely high compared with the controls. Streptococci mutans were detected in high numbers in 31% of the RT subjects
Hommez et al. (2008) evaluated the microflora in root canals of necrotic teeth after radiotherapy of the head and neck region and detected mainly subspecies of Lactobacillus spp.,
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Capnocytophaga spp., and Actinomyces spp.) and concluded that, the diversity of root canal microflora increases significantly, after head-neck radiotherapy
Meurman (2010) stated that, In a study from Sweden, Candida albicans was found in one or more sites in 54% of the subjects who had received radiotherapy to the head and neck in comparison to 15% of the controls. These patients also harbored enterococci in 38% versus none of the controls. Lactobacillus spp. was detected in 92% of the subjects and the proportion of the species was high compared with the controls. Mutants streptococci were also detected in high numbers; 31% in the patients vs. 23% in controls. On the other hand, in a study from China, mutants streptococci were not isolated in radiotherapy patients while lactobacilli, S. mitis and S.salivarius was the predominant caries-related oral bacteria following radiotherapy and added that, Bacteria in gingival pockets in head- and neck-irradiated patients have also been investigated. A comprehensive study from Hong Kong showed that the major components of sub-gingival microbiota appear similar to that of gingivitis sites in the normal population although among the radiotherapy patients bacterial or fungal species uncommon in normal subjects were also detected.
These species included microorganisms such as Gemella, Peptostreptococcus, Staphylococcus, Stomatococcus, Streptococcus Actinomyces, Eubacterium, Lactobacillus, Propionibacterium, Neisseria, Veillonella, Bacteroides, Campylobacter, Capnocytophaga, Fusobacterium, Kingella, Porphyromonas, and Prevotella.
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SALIVA
aliva is the most available and non-invasive biofluid of the Shuman body that permanently "bathes" the oral cavity and is trying to cope with an ever-changing milieu (Greabu et al., 2009).
Total or whole saliva refers to the complex mixture of fluids from the salivary glands, the gingival fold, oral mucosa transudate, in addition to mucous of the nasal cavity and pharynx, non-adherent oral bacteria, food remainders, desquamanted epithelial and blood cell, as well as traces of medications or chemical products Whole saliva is most frequent used in diagnosis of systemic diseases (Greabu et al., 2009).
The major salivary glands produce approximately one liter of saliva per day. The average unstimulated flow rate is 0.4 ml/min and the average stimulated flow rate is 2.0 ml/min. The commonly accepted values for lower limits of normal salivary function are 0.1 – 0.2 ml/min unstimulated flow rate and 0.7 ml/min stimulated flow rate, although the definition of adequate salivary volume to prevent oral/dental disease and maintain comfort is not clearly defined. In addition to loss of salivary volume, changes in the constituents of saliva and changes in viscosity impact salivary function (Rankin et al., 2008).
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Salivary composition
Saliva is a complex secretion. 93% by volume is secreted by the major salivary glands and the remaining 7% by the minor glands. 99% of saliva is water and the other 1% is composed of organic and inorganic molecules (Llena, 2006).
Inorganic components
The most abundant component in saliva is water(approximately 99%), followed by ions Na+,Cl–, 2+ + – – – – 2+ Ca ,K ,HCO3 ,H2PO4 , F , I ,Mg , thiocyanate. The ionic composition of saliva is different from the plasma although derived from it. The hypo tonicity facilitates taste sensitivity and hydrates various organic compounds that form a protective coating on the oral mucosa. Resultant bicarbonate serves as a buffering agent and calcium and phosphate neutralize acids that would otherwise compromise tooth mineral integrity (Greabu et al., 2009).
Organic components
Saliva includes a large number of organic compounds such as: urea, ammonia, uric acid, glucose, cholesterol, fatty acids, mono–, di–, and triglycerides, phosphor and neutral lipids, glycolipids, amino acids, steroid hormones and proteins that aid in the protection of oral cavity tissues, including mucins, amylases, agglutinins, glycoproteins, lysozymes, peroxidases, lactoferrin and secretory IgA. Non-immune factors include
56 Review of Literature lactoferrin, lysozyme, myeloperoxidase, histatins, cystatins, mucin G1 and G2, and defensins. In addition, these macromolecules form a viscoelastic mucosal coat and tooth enamel pellicle and aggregate and cleanse bacteria and debris from the oral cavity. Saliva contains a variety of antimicrobial constituents and growth factors (Greabu et al., 2009).
The role of saliva in oral health
Saliva plays an important role in maintaining oral and dental health. In addition to solubilizing food and physically cleansing the oral cavity of detritus, saliva exerts a range of protective functions on oral tissues and teeth, including facilitating adhesion of microorganisms to teeth and other oral surfaces, and buffering dietary acids (Humphery and Williamson, 2001). Due to its composition and functions saliva could have a significant role in controlling and /or modulating oxidative damages in oral cavity (Greabu et al., 2009). In addition to other functions saliva plays in protecting teeth from caries which can be summarized under four aspects: diluting and eliminating sugars and other substances, buffer capacity, balancing demineralization/remineralization and antimicrobial action. Furthermore, Saliva is a promising option for diagnosing certain disorders and monitoring the evolution of certain pathologies or the dosage of medicines or drugs (Llena, 2006).
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Salivary imunoglobulins
The salivary glands have a local immunologic system which comprises largely seceretory IgA with small amounts of IgG, IgM. Saliva contains about 19 mg/100ml IgA.In contrast, only1.4mg of IgG and 0.4mg of IgM are found per100ml of saliva (Brandt Zaeg et al., 1970).
Immunoglobulin G (IgG)
It is the most abundant class of immunoglobulin in the body. These molecules achieve significant concentrations in both vascular and extra-vascular spaces, have a relatively long half life, cross placenta and are able to activatecomplement. This class of immunoglobulin contribute to immunity against many infecting agents that have a blood born dissemination including bacteria virus, parasites and some fungi .In addition, it provides antibody activity in tissue (Bellanti, 1995).
Immunoglobulin M (IgM)
It is the largest of the immunoglobulin molecules and because of its large size; it is restricted almost entirely to the intravascular space. These macromolecules are highly efficient agglutinators of particulate antigens such as bacteria and red blood cells and they fix complements with high degree of efficiency. This class is of the greatest importance in the first few days of the primary immune response (Bellanti, 1995).
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Immunoglobulin A (IgA) Salivary secretory immunoglobulin A (SIgA) was first demonstrated by Tomasi & Ziegelbaum in 1963 (Sahinger and Cohen, 2004). It is the dominant immunoglobulin in external secretions that bathe mucosal surfaces and it contributes 60% of the total immunoglobulin count in the saliva. Relative numbers of IgA-producing plasma cells are higher in the submandibular and sublingual glands compared to the parotid glands, and even higher in certain minor glands, leading to differing levels of SIgA in the secretions from these glands. It is speculated that greater density of plasma cells in certain glands may be due to increased antigenic interactions in those parts of the mouth (Marcotte and Lavoie 1998).
Structure of SIgA SIgA exists as a polymeric molecule composed of IgA monomer, a j chain and secretory components (SC). Each nonnumeric IgA is formed of 4 polypeptides bonds (Marcotte and Lavoie 1998). In humans, there are two IgA subclasses, IgA1 and IgA2, which occur in similar proportions in saliva and other secretions. The differences depend on Fc domain which makes IgA1, but not IgA2 susceptible to cleavage and inactivation by bacterial proteases (Hagewald et al., 2002).
Role of secretory IgA
Secretary IgA is considered to be the first line of defense of the host against pathogens that colonize or invade mucosal
59 Review of Literature surfaces. Salivary IgA antibodies could help maintain the integrity of the oral surfaces by preventing microbial adherence to epithelial and tooth surfaces, by neutralizing enzymes,toxins and viruses, or by acting in synergy with other antibacterial factors such as lysozyme, lactoferrin, salivary peroxidase, and mucins. Salivary IgA may also prevent the penetration of food antigens in the oral mucosa (Jafferadh et al, 2010). Furthermore, SIgA exerts its anti-inflammatory protective functions and down –regulates inflammation by inhibiting IgG and IgM modulated functions (Hagewald et al., 2002).
Factors affecting Secretory IgA The level of salivary IgA may vary according to age, hormonal factors, smoking habits, emotional states, physical activity (Marcotte and Lavoie, 1998; Bosch 2002 and Jafferadh, 2010) and is influenced by mechanisms like bacterial load, individual host response or genetic background (Hagewald et al., 2002). Furthermore, the active transport mechanism into saliva for SIgA serves as a rate-limiting factor, (Bosch, 2002) and salivary levels of SIgA decrease as flow rates increase (Kugler et al., 1992; Smith et al., 1992; Eliasson 2006 and Sonesson et al., 2011).
Secretory IgA in systemic diseases
Studies have explored the relationship between salivary and systemic immunoglobulins in patients with other oral or systemic conditions.
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Tenovuo et al. (1986) increased concentrations of salivary IgG and IgA were found in periodontitis patients with non-insulin-and insulin-dependent diabetes, compared to non- diabetic periodontitis patients and periodontally healthy controls.
Barr-Agholme et al. (1998) investigated the salivary concentration of immunoglobulins sIgA, IgM, and IgG and albumin in patients with Down's syndrome, compared to healthy controls. They found that results from analysis of sIgA, IgM, total IgG, and albumin did not differ signifcantly between the two groups. However, the proportion of IgG1 was significantly higher in the Down's syndrome groups. The authors concluded that an alteration in the distribution of IgG subclasses occurred in the saliva of patients with Down's syndrome.
Myint et al. (1997) measured IgA concentration in parotid saliva from HIV-positive and HIV-negative individuals with healthy gingiva, chronic gingivitis, chronic marginal periodontitis, and necrotizing ulcerative periodontitis and found that the IgA concentration was elevated in all patients harboring HIV.
Zuabi et al. (1999) evaluated the effect of smoking on periodontal status and the composition of whole saliva in subjects with established chronic periodontitis before and after periodontal therapy. They found that subjects with periodontitis
61 Review of Literature had elevated concentrations of salivary electrolytes and proteins compared to controls. Smokers exhibited greater disease severity and decreased sodium, calcium, and magnesium concentrations. On the other hand, smokers responded favorably to treatment, resulting in the elimination of the differences in salivary composition
Secretory IgA and oral diseases
Secretory IgA and Caries
Dental caries is a multifactorial disease and one of the major contributing factors is saliva. Salivary components, its flow, viscosity, buffering capacity, etc. play a major role in the prevention, initiation, and progression of the disease It helps in the prevention of the caries by its antibacterial effect. Many constituents of the saliva, both immunoglobulins and non immunoglobulins contribute to this antibacterial effect. Studies of dental caries have reported contradictory results. Some studies attempted to correlate salivary IgA antibodies with presence of active caries. On the other hand, other studies correlated dental caries with an increase of salivary SIgA
De Farias and Bezerra (2003) performed measurements of total salivary IgA, and IgM in caries-free children and children with early childhood caries Children with early childhood caries presented significantly higher levels of total salivary IgA and IgG.
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Thaweborn et al. (2008) determined the level of secretary IgA, ph, flow rate mutans streptococci (MS)and Candida in saliva of children with rampiant caries compared to those of caries free. It was found that children with rampant caries presented with significantly higher levels of salivary SIgA, MS and Candida. However, the mean values for salivary flow rates and pH were similar between the groups. The results revealed that children with rampiant caries had significantly higher levels of SIgA, MS and Candida in their oral cavities. This finding supported the hypothesis that higher levels of salivary SIgA reflected a past exposure of the host to cariogenic microorganisms
Jafarzadeh et al. (2010) reported that SIgA levels increased with age up to 60 years and then slightly decreased in subjects aged 61 to 70 years.
Rnadheer et al. (2011) deduced that there was an increase in s-IgA levels in caries-active mouth to give protection mechanism against dental caries and Streptococcus mutants which are active in caries active mouth.
The SIgA antibodies can play an important role in control of dental caries In contrast, to the previous results
Camling et al. (1987) noted that individuals with active caries and/or with high decay missing filling surface (DMFS)
63 Review of Literature indices manifested a tendency to present lower IgA levels in total saliva than individuals with a low caries experience.
Gregory et al. (1990) also reported a correlation between low rates of caries activity and higher levels of salivary IgA antibody levels in adults and those caries-resistant subjects synthesize antibodies of different specificities than caries- susceptible patients.
Tenovuo et al. (1992) studied association between salivary non-immunoglobulin (hypothiocyanite, agglutinins) or immunoglobulin (total IgA, anti-Streptococcus mutans IgA) antimicrobial factors, and the prevalence of dental caries in young adults. These antimicrobial factors were also analyzed relation to the salivary levels of mutans streptococci (MS). They found that, The amount of MS correlated significantly with the number of initial caries lesions but not with other caries indices, the group with no caries had significantly more hypothiocyanite and anti-S. Mutans IgA antibodies in whole saliva than those with initial caries lesions and none of the antimicrobial factors alone showed any significant association with salivary MS counts.
Parkash et al. (1997) Observed that children with caries had higher levels of IgG and IgA in the serum but their saliva had lower levels of total IgG and IgA.while, IgM levels in caries children and controls were not significantly different. Higher levels of Streptococcus mutans specific IgA were
64 Review of Literature detected in the saliva out of 75% of children with caries compared to 22% of controls.
Rose et al. (1997) compared IgA antibody levels with Streptococcus mutans in whole and parotid saliva from caries- susceptible and caries-resistant patients. Whole salivary Streptococcus mutans numbers were significantly greater in the caries-susceptible group than in the caries-resistant group. Moreover, Whole saliva, but not parotid saliva, from caries- susceptible children had significantly higher levels of IgA antibodies to S. mutans than saliva from caries-resistant children.
Cogulu et al. (2006) compared the caries prevalence and salivary secretary IgA (SIgA), salivary pH, buffering capacity and flow rate between
Downs syndrome and control subjects and found that patients with Downs syndrome had a significantly lower prevalence of caries and significantly higher levels of salivary SIgA.This finding tends to support the hypothesis that higher levels of salivary SIgA may protect against dental caries.
Bagherian et al. (2008) found higher levels of SIgA in the saliva of children who were colonized for less than 6 month and had a low DMFT score than those who had than harbored S. mutans for a longer period of time (24 months) and had a high DMFT score.
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Chawada et al. (2011) investigated the relation between SIgA and caries. Subjects of the study were categorized into two groups based on decayed, missed filled scores of permanent and deciduous teeth into Group I and II (caries active) Group III (caries free) The total salivary concentration of SIgA was statistically significantly higher in the caries free group than that of both the caries active groups Furthermore, a significant inverse correlation was found between SIgA and the caries activity.
Doifode and Damle (2011) investigated the role of immune response as a natural protection against caries in children and reported higher SIgA in caries free group compared to caries active group and deduced that naturally occurring salivary IgA antibodies can play an important role in immunological control of dental caries.
On the other hand, some studies found there was no correlation between SIgA and dental caries
Smith et al. (1990) reported that the level of whole salivary IgA2 antibodies to mutans streptococci were relatively equal in caries free children as compared with caries active children
Koga et al. (2004) studied, five groups of caries-free children, children with caries, children with rampant caries, young adults with and without caries and reported no
66 Review of Literature correlation between mutans streptococci counts and anti- Streptococcus mutans IgA levels was observed in the studied groups. A correlation between increase anti-Streptococcus mutans IgA levels and caries-free status was observed among young adults but not among children.
Shifa et al. (2008) investigated caries active children in comparison to caries free children and the study didn’t show any correlation between SIgA.
levels and caries status and found there was an increase in the mean IgA value of the caries resistant concerning the mean IgA value of however the results were not statistically significant which did not show any correlation between SIgA levels and caries status.
Rhaskova et al. (2009) studied on children with diabetes, asthmatic disease and the children with orthodontic apparatuses. The results showed that 2/3 of the children with diabetes have low values of SIgA, middle values of SIgA are most Frequently in children with asthmatic disease. One half of the children with orthodontic apparatuses have high values of SIgA. Results also showed, there is no dependence between secretary immunity and dental caries in children. Moreover, Dental caries index (DMF) is approximately equal for children with very low and very high values of SIgA however it is lower in the group of children with average values.
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Secretary IgA and Periodontitis
Individuals with periodontal diseases typically demonstrate salivary antibodies, as well as systemic immune responses, to putative periodontal pathogens. A number of studies have investigated the relationship of both specifc and total salivary immunoglobulin to disease status.
Harding et al. (1980) reported decreased amounts of monomeric IgA and IgG, but elevated SIgA in saliva of patients with necrotizing ulcerative gingivitis.
Ebersole et al. (1982) studied the association between periodontal disease in humans and serum and salivary antibody to Actinobacillus actinomycetemcomitans (Aggregatibactera- ctinomycetemcomitans) strain Y4 (IgM, IgG, IgA and IgE isotypes in serum and IgA in parotid saliva) was determined .Serum and salivary IgA and serum IgE antibody levels were significantly increased in patients with both localized and generalized types of juvenile periodontitis when compared to all other patient groups.
Sandholm and Gronbald (1984) reported increased amounts of IgA, IgG and IgM in whole saliva from 21 patients with localized aggressive periodontitis, compared to 27 periodontally healthy siblings and 17 controls.
Schenck et al. (1993) measured salivary IgA specific for a number of periodontal pathogens in a model of experimental
68 Review of Literature gingivitis and demonstrated that individuals with low bleeding scores had elevated anti-S.mutans, A.actinomycetemcomitans, and Eubacteriun saburreum antibodies
Fukui et al. (2004) investigated the relationship between the severity of periodontal disease and the salivary immunoglobulin SIgA high level of SIgA directed to GroEL periodontopathic bacteria by studying subjects with Periodontitis and controls. Higher level of SIgA were found in subjects with periodontitis compared to controls.
In contrast, Basu et al. (1976) evaluated IgG and IgA in whole saliva from 12 periodontitis patients and found increased amounts of IgG and decreased IgA concentrations before therapy, compared to post-treatment levels.
Reiff et al. (1984) examined serum and salivary concentrations of IgG and IgA in periodontitis patients before and after initial therapy, and found a reduction in both IgG and IgA after treatment.
Gregory et al. (1992) reported extensive degradation of IgG and IgA in crevicular fluid samples on from periodontal disease sites of localized juvenile periodontitis patients in comparison to little degradation in healthy sites.
Bokor (1997) reported that IgA levels in mixed unstimulated saliva were lower in subjects with more pronounced gingival inflammation.
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Hagewald et al. (2000) evaluated total and P. gingivalis- reactive salivary IgA in generalized aggressive periodontitis patients, compared to age-and gender-matched periodontally healthy controls. They found a significantly lower concentration and rate of secretion of total salivary IgA in the experimental group.
Hagewald et al. (2002) investigated the hypothesis that aggressive periodontitis patients have impaired oral secretary immunity. The test group was made-up of aggressive periodontitis patients and age and gender-matched periodontally healthy controls. Total IgA, IgA subclass 1, IgA subclass 2 and IgA reactive to Actinobacillus actinomycetemcomitans Y4,Treponema denticola and Candida albicans were determined by enzyme- linked immunosorbent assay in whole unstimulated and stimulated saliva. Results indicated an inhibition of total secretary IgA. In particular an IgA subclass 1-specific decrease in aggressive periodontitis was noted, while the bacteria-reactive humoral immune system in saliva was activated.
On the other hand, some studies found no correlation between Secretary IgA and Periodontitis
Mansheim et al. (1980) evaluated salivary IgA concentration to P. gingivalis in patients with localized and generalized aggressive periodontitis and found no difference when compared to controls.
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Sandholm et al. (1987) have suggested that salivary antibody may be useful for differentiating among periodontal diseases. They reported an increased concentration of whole salivary IgG in 34% of patients with moderate chronic periodontitis, and in 57% of patients with severe chronic periodontitis. Salivary IgG antibody to A.actinomycetemcomitans was significantly increased in 55% of individuals with untreated localized aggressive periodontitis, and in 28% of treated subjects with that disease. Furthermore, 28% of the patients with chronic periodontitis had significantly elevated salivary IgG antibody levels to
A. actinomycetemcomitans subtype Y4. , however, IgA concentrations did not show appreciable difference among study groups.
Hagewald et al. (2003) monitored for total salivary IgA and IgA reactive to Porphyromonas gingivalis in resting and stimulated whole saliva in patients with generalized aggressive periodontitis during non-surgical and antibiotic treatment. It was found that, periodontal treatment of aggressive periodontitis did not appear to affect salivary IgA, and there were no significant correlations of IgA to the clinical parameters.
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ORAL MICROBIOTA
he oral microbiota of humans is highly complex and T diverse. It is composed of more than 300 bacterial species, to which may be added protozoa, yeasts, and mycoplasmas. Their distributions vary qualitatively and quantitatively according to the habitat.
(i) Teeth:
On teeth, microorganisms colonize in a dense mass forming dental plaque. Dental plaque consists of microbial communities organized in a complex matrix composed of microbial extracellular products and salivary compounds. The microbial composition of dental plaque varies according to the site and the sampling time. Dental plaque develops preferentially on surfaces protected from mechanical friction, such as the area between two teeth (proximal surface), the subgingival area (gingival crevice), and the pits and fissures of the biting surfaces. The predominant organisms isolated from supragingival dental plaque are gram-positive, facultatively anaerobic bacteria, particularly Actinomyces spp. and streptococci). Gram-negative bacteria of the group Veillonella, Haemophilus, and Bacteroides are regularly isolated but in lower proportions.
In a healthy subgingival crevice, the total number of cultivable bacteria is relatively small the subgingival plaque is
72 Review of Literature also dominated by gram-positive organisms (Actinomyces and Streptococci). It seems that the microbiota from the gingival crevice is an extension of supragingival plaque.
Blackpigmented gram-negative rods including Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella melaninogenica, Prevotella intermedia, Prevotella loescheii, and Prevotella denticola are rarely isolated from a healthy gingival crevice.
(ii) Mucosal surfaces:
The oral mucosa of the gingiva, palate, cheeks, and floor of the mouth are colonized with few microorganisms. Streptococci constitute the highest proportion of the microbiota in these sites, with a predominance of S.oralis and S. sanguis, Genera Neisseria, Haemophilus, and Veillonella have also been isolated On the tongue, a higher bacterial density and diversity is found Streptococcus spp. (S.salivarius and S.mitis) and Veillonella spp. were the predominant members of the microbiota.
Other major groups isolated include Peptostreptococcus spp., gram-positive rods mainly Actinomyces spp., Bacteroides spp., and other gram-negative rods.
Black pigmented obligate anaerobic rods and spirochetes, which are closely associated with periodontal diseases, have been recovered in small numbers.
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Organisms that are found in saliva are derived from the dislodgement of bacteria colonizing the various oral sites. The microbial composition of saliva is similar to that of the tongue (Marcotte and Lavoie, 1998).
Ecosystem
An ecosystem consists of the microbial community living in a defined habitat and the biotic surroundings composed of physical and chemical elements. The oral ecosystem is composed of the oral microorganisms and their surroundings.
The growth of oral microorganisms is influenced by a variety of factors.
Physicochemical factors:
The physicochemical factors result from the combined action of host, microbial, and external factors. In all in vivo and in vitro systems, the growth of microorganisms is influenced by five important variables: temperature, pH, availability of water, availability of nutrients, and oxidation-reduction potential As the mouth is constantly bathed by saliva and reticular fluid, water is not considered to be a limiting factor.
Temperature:
The temperature in the oral cavity is relatively constant (34 to 36°C), which allows a wide range of microorganisms to grow. The temperature may be more variable on the mucosal
74 Review of Literature and tooth supra gingival surface. During food intake, microorganisms colonizing these sites are exposed to hot and cold meals and probably must adapt to these extreme variations of temperature. However, to our knowledge, no data are available on the effect of this short period of temperature variation on the metabolism of oral bacteria (Marcotte and Lavoie, 1998). pH: The pH is an important parameter in oral microbial ecology. Frequent sugar intake favors the growth of aciduric bacteria such as Lactobacillus and S. mutans and predisposes to caries formation An increased colonization by S. mutans was demonstrated by simply rinsing the mouth with lowpH buffers. In vitro studies have also shown that gradual decreases in pH in glucose pulsed cultures favored S. mutans and Lactobacillus while populations of S. sanguis, S. mitior, P. intermedia, and F. nucleatum were reduced (McDermid et al., 1986).
The subgingival area is bathed by gingival fluid and is not controlled by the buffering salivary activity. The pH in the gingival crevice may vary between 7.5 and 8.5, while the crevicular fluid ranges from pH 7.5 to 7.9.
An alkaline pH in gingival crevices and periodontal pockets may exert a selective force towards the colonization of periodontopathogens (McDermid et al., 1988).
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Oxidation reduction potential and anaerobiosis:
Many enzymatic reactions are oxidation-reduction reactions in which one compound is oxidized and another compound is reduced. The proportion of oxidized to reduced components constitutes the oxidation-reduction potential. The mouth is characterized by a wide range of oxidation-reduction potentials, allowing the growth of aerobic, facultative anaerobic and anaerobic bacteria In general, the dorsum of the tongue and the buccal and palatal mucosa are aerobic environments with positive oxidation-reduction potential, thus better supporting the growth of facultative anaerobic bacteria. The gingival crevice and the proximal surfaces of the teeth (surfaces between teeth) possess the lowest oxidation-reduction potential and the highest concentration of anaerobic bacteria (Theilade, 1990).
Nutrients:
In the oral cavity, microorganisms living in the supra gingival environment have access to nutrients from both endogenous (saliva) and exogenous (diet) origin. Saliva is an important source of nutrients and can sustain normal growth of microorganisms in the absence of exogenous nutrients.
The gingival crevice is not exposed to dietary components and saliva, and its principal source of nutrients is the gingival crevicular fluid. The crevicular fluid originates from plasma and is an excellent source of nutrients for fastidious
76 Review of Literature microorganisms. It contains growth factors such as vitamin K required by P.gingivalis, a gram-negative rod associated with adult periodontitis.
Many nutritional interrelationships also occur between microorganisms. Some microorganisms cooperate for the degradation of nutrients. Some bacteria also use nutrients and other substances produced by other microorganisms (Marcotte and Lavoie, 1998).
Host defense mechanisms:
The supragingival environment of the oral cavity is controlled primarily by saliva. The continuous flow of saliva increased by the muscular activity of the lips and tongue removes a large number of bacteria from teeth and mucosal surfaces. Saliva also contains several specific and nonspecific defense factors. SIgA is the principal specific defense factor of saliva,. The nonspecific defense factors include mucins, nonimmune salivary glycoproteins, lactoferrin, lysozyme, peroxidase, histatins, and cystatins (Tabak, 1990).
Age: The composition of the oral microbiota varies with the age of the host. Age-related changes in the oral microflora include those due to teeth eruption, changes in dietary habits, hormones, salivary flow, the immune system, or other factors (Pearce et al., 1995).
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Hormonal changes: It is well known that in humans, puberty and pregnancy are characterized by increased levels of steroid hormones in plasma and subsequently in the crevicular fluid and saliva Several investigators have described a transient increase in the number of black-pigmented gram-negative anaerobic bacteria in the subgingival microbiota during puberty or pregnancy. Kornman and Loeshe reported an increased proportion of Prevotella- intermedia in the subgingival microbiota of pregnant woman, corresponding to an increased levels of estrogens and progesterone in plasma. They also demonstrated in vitro that progesterone or estradiol can substitute for vitamin K as an essential growth factor for P. intermedia . In contrast; other studies were unable to find any changes in the subgingival microbiota during puberty and pregnancy (Marcotte and Lavoie, 1998).
Stress: Host stress may be associated with changes in hormones, salivary flow, dietary habits, and immune response. These changes in the intestinal microbiota include a reduction in numbers of lactobacilli (Ballieux, 1991).
Genetic factors: The genetic background appears to influence the susceptibility to caries and periodontal diseases. This could in part be because the host genetic factors select for a microbiota with varying potential for causing oral diseases. The selection of a certain microbiota by the host is dependent on inherited 78 Review of Literature immune factors, physiology, metabolism, mucus composition, or receptor-and interactions (Moore et al., 1993).
Adherence: Adherence is essential for providing resistance to the flow of saliva. Adherence is mediated by adhesins on the surface of bacteria and by receptors on the oral surface. Microbial adhesins consist of polysaccharides, lipoteichoic acids, glucosyl transferases, and carbohydrate-binding proteins (lectins). These adhesins are found as cell wall components or are associated with cell structures, such as fimbriae, fibrils or capsules. The receptors may be salivary components (mucins, glycoproteins, amylase, lysozyme, IgA, IgG, praline rich proteins, and statherins) or bacterial components (glucosyltransferases and glucans) that are bound to oral surfaces. The adherence may result from nonspecific physicochemical interactions between the bacteria and the oral surfaces (Scannapiecom, 1994).
Bacterial interactions:
A variety of beneficial and antagonistic interactions may help in maintaining the homeostasis of the oral microbiota. Co aggregation is one example of commensalism and synergism that occurs between microbial species. Co aggregation allows the indirect adherence of some bacteria on oral surfaces. In addition, it was demonstrated that coaggregated cells were more resistant to phagocytosis and killing by neutrophils in vitro and in vivo several other examples of positive interactions are likely to occur in the oral cavity. The utilization of oxygen by
79 Review of Literature facultative anaerobic bacteria reduces the oxygen concentration and to levels that allow the colonization of anaerobic bacteria Different bacterial species may also cooperate in the utilization of substrates that they could not metabolize alone (Ochiai et al., 1993).
Diet: Frequent consumption of a high-sucrose diet enhances the development of S.mutans and Lactobacillus. The fermentation of sucrose into lactate generates a low pH, favoring acidogenic and acidophilic bacteria. The substitution of sucrose with weakly fermentable sugar alcohols such as xylitol results in a reduction of S.mutans numbers and caries, it was found that a high-starch diet favored an increase in the proportion of Enterococcus faecalis while a high-protein diet favored an increase in Lactobacillus murinus (Olsson and Svanberg, 1991).
Oral hygiene and anti microbial agents:
Oral hygiene is one of the most important factors in the maintenance of oral homeostasis and oral health. The mechanical removal of plaque by tooth brushing and flossing can almost completely prevent caries and periodontal diseases (Mathiesen et al.,1996).
Drugs and diseases:
Patients suffering from xerostemia have higher levels of mutans streptococci, lactobacilli, staphylococci, and Candida, while the levels of S.sanguis, Neisseria, Bacteroides, and Fusobacterium are reduced compared with those in a healthy
80 Review of Literature individual. They are also more susceptible to dental caries and candidiasis.
Antibiotics that are given orally or systemically for the treatment of different infections may enter the oral cavity via saliva and gingival crevicular fluid and lead to a imbalance in the oral microbiota Antibiotics may suppress some resident bacterial populations which can result in overgrowth of antibiotic-resistant bacteria, infections by opportunist pathogens such as Candida, and colonization by exogenous potential pathogens such as yeasts and members of the Enterobacteria (Sanders and Sanders, 1984).
Other factors:
Many other external factors may affect the oral microbiota; these include the wearing of dentures or partial dentures smoking, oral
Contraceptives usage malnutrition host macro environment and various exposures to exogenous bacterial species (Marcotte and Lavoie, 1998).
Oral Microbiota Associated with Oral Diseases
Caries and periodontal diseases are infectious diseases associated with resident microorganisms of the dental plaque. There are two major hypotheses about the role of plaque in oral diseases The specific plaque hypothesis proposes that only a
81 Review of Literature few microorganisms are involved in the oral disease process, while the other hypothesis (nonspecific) considers that diseases result from the interaction of the whole plaque with the host. Several studies described the oral microbiota associated with caries and periodontal diseases and identified the specific etiological agents (Marcotte and Lavoie, 1998).
Caries: The microbial flora of the oral cavity are rich and extremely diverse. This reflects the abundant nutrients and moisture, and hospitable temperature, and the availability of surfaces on which bacterial populations can develop. The presence of a myriad of microorganisms is a natural part of proper oral health. However, an imbalance in the microbial flora can lead to the production of acidic compounds by some microorganisms that can damage the teeth and gums. Damage to the teeth is referred to a dental caries (Lerner and Lerner, 2003).
Dental caries is a bacterial disease of the dental hard tissues; it is characterized by a localized, progressive, molecular disintegration of the tooth structure. The development of caries is associated with dental plaque of smooth coronal surfaces, pits, and fissures. Caries may also appear on root surfaces that are exposed to the oral environment as a result of gingival recession. The demineralization of teeth (enamel, dentine, and cementum) is caused by organic acid produced from the bacterial fermentation of dietary carbohydrates. 82 Review of Literature
The frequent ingestion of carbohydrates may lead to the selection of bacteria that are acidogenic (capable of producing acid from carbohydrates) and aciduric (capable of tolerating acid) and concurrently to a lowpH environment. These conditions favor the solubilization of tooth minerals.
The complexity of the bacterial community in dental plaque of humans has made it difficult to determine the single bacterial agent of caries.
However, there is considerable evidence that mutans streptococci (particularly S.mutans and S.sobrinus) and Lactobacillus are involved in the initiation and progression of caries. Species such as Actinomyces spp., S.mitis, Veillonella spp. and Candida spp. have been associated with enamel caries as well (Marcotte and Lavoie, 1998).
Nyvad and Kilian (1990) observed that, the microflora from plaque samples of root caries associated with the highest mineral loss was dominated by either Actinomyces viscosus or a combination of mutans streptococci and Lactobacillus species. Plaque from root surfaces with less pronounced mineral loss harbored a more complex microflora comprising gram-positive rods, mutans streptococci, Streptococcus mitis biovar 1, Veillonella spp., gram-negative rods, and low numbers of lactobacilli. In the latter samples, individual variations in the proportions of mutans streptococci, Actinomyces species. and Veillonella parvula biotypes.
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Nyvad and Kilian (1990) compared the initial microflora on enamel in caries-active and caries-inactive adolescents. Early plaque from caries-inactive individuals differed from that of caries-active individuals by significantly higher proportions of S. sanguis and IgA1 protease producing streptococci. In caries-active individuals, there was a tendency to elevated levels of S. mitis biovar 1 than. In addition; caries-active individuals were colonized by significantly higher numbers of mutans streptococci on the enamel surfaces. However, in both groups Streptococcus mutans (serotype c) comprised less than or equal to 2% of the early streptococcal flora. Streptococcus gordonii, S. mitis biovar, and Streptococcus salivarius were present in low proportions and did not show differences in distribution that could be related to caries activity.
Drucker et al. (1995) compared salivary levels of mutans streptococci and Lactobacillus in 5-year-old children from two ethnic groups, and observed that, there were no significant differences in mutans streptococci or Lactobacillus levels between the two ethnic groups. However, strong correlations were found between caries experience and levels of both mutans streptococci and Lactobacillus in each ethnic group. Furthermore, mutans streptococci and Lactobacillus levels correlated strongly with one another.
Brailsford et al. (2001) isolated the predominant aciduric microflora from root caries lesions and sound root surfaces in subjects with or without root caries and found that, The 84 Review of Literature predominant aciduric bacteria from root lesions were lactobacilli and A. israelii, while from sound root surfaces in subjects with root caries, A.gerencseriae comprised over 60% of aciduric isolates mutans streptococci were not among the aciduric isolates. Subjects without root caries harbored fewer bacteria, and S. anginosus and S. oralis were the predominant aciduric bacteria.
Lerner and Lerner (2003) stated that bacteria that are typically present as primary colonizers include Streptococcus, Actinomyces, Neisseria, and Veillonella. Secondary colonizers include Fusobacterium nucleatum, Prevotella intermedia, and Capnocytophaga species. With further time, another group of bacteria can become associated with the adherent community.
These bacteria include Campylobacter-rectus, Eikenella corrodens, Actinobacillus actinomycetemcomitans, and the oral spirochetes of the genus Treponema.
Beighton et al. (2004) stated that, the development of dental caries depends on oral bacteria metabolising dietary carbohydrates to produce acid. Although a wide spectrum of acidogenic flora maybe involved, Streptoccus mutans has been most consistently identified as the most significant and that Lactobacilli and yeasts are commonly associated with caries and their presence has been associated with sugary diets.
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Munson et al. (2004) studied the bacterial community of the middle and advancing front of carious dental lesions by cultural and molecular analyses. Only three taxa, Streptococcus mutans, Rothia dentocariosa, and an unnamed Propioni bacterium species were found. The predominant taxa by anaerobic cultivation were Propioni bacterium species. Olsenella profusa and Lactobacillus rhamnosus. The predominant taxa in the molecular analysis were Streptococcus mutans, Lactobacillus gasser-ijohnsonii and Lactobacillus rhamnosus. Moreover, no significant difference between the compositions of the microflora in the middle and advancing front samples was detected.
Beighton (2005) stated that the essential role of mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) in the caries process is not proved, caries occurs in the absence of these species and their presence does not necessarily indicate caries activity. Other oral bacteria, non-mutans streptococci, Actinomyces spp. and Bifido bacterium spp., are acidogenic and aciduric. They out number mutans streptococci in dental plaque, and there are data which support a role for these bacteria in the initiation and progression of caries and that molecular studies demonstrate the great diversity and complexity of the flora associated with caries.
Luhan and Patel (2010) deduced that the mouth contains a wide variety of oral bacteria, but only a few specific species of bacteria are believed to cause dental caries: Streptococcus mutants and Lactobacilli. Among them Lactobacillus 86 Review of Literature acidophilus, Actinomyces viscosus, Nocardia spp., and Streptococcus mutantsare most closely associated with caries, particularly root caries.
Periodontal diseases: Periodontal diseases are a general term describing the inflammatory pathologic state of the supporting tissues of teeth. Periodontal diseases can be grouped into two major categories, gingivitis and periodontitis. Each can be further divided according to the age of the patient (pre-pubertal, juvenile, adult), disease activity and severity (rapid, acute, chronic), and distribution of lesions (localized or generalized).
In a healthy gingival crevice, the microbiota is dominated by facultative gram-positive bacteria. The predominant gram-positive bacteria are Actinomyces naeslundiigen species 2 (formerly A. viscosus), A. naeslundii, S. sanguis, S.mitis, and Peptostrepto- coccus micros. Gram-negative rods include F.nucleatum, P. intermedia Veillonella, Wolinella, Capnocytophaga, and Haemophilus.
Chronic adult periodontitis is the most common form of advanced periodontal disease. The microbiota is extremely diverse. The predominant species include P. gingivalis, P. intermedia, Bacteroides forsythus, A. actinomycetem- comitans, W. recta, E. corrodens, Treponema denticola and P. micros.
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Other more acute and rapid forms of periodontal diseases seem more associated with particular microbial groups, such as in localized juvenile periodontitis which is closely associated with high numbers of Aggregatibacter actinomycetemcomitans.
Saini et al. (2003) carried out to compare the normal aerobic and anaerobic bacterial oral flora with flora from deep seated dental caries, gingivitis and adult periodontitis and deduced that the most common aerobe, was Streptococcus mutans in dental caries, Staphylococcus aureus on gingivitis and Actinobacillus-actinomycetemcomitans in periodontitis. Among the anaerobes, lactobacilli were the commonest in dental caries, Actinomyces in gingivitis and Porphyromonas gingivalis in periodontitis.
Do Vale et al. (2004) indicated that Actinobacillus (Haemophilus) actinomycetemcomitans and Fusobacterium nucleatum as etiologic agents of periodontal disease and pointed out that a marked difference between A.(H.) actinomycetemcomitans and Fusobacterium nucleatum cytoplasmic extracts in their antiproliferative activity, regarding the antigen concentration required for maximum inhibition and their vulnerability to heating and proteolytic treatment.
Tanner et al. (2006) found that many Streptococcus and Streptococcus-like species. (Gemella and Granulicatella), Eubacterium sulci, Actinomyces odontolyticus, Campylobacter- concisus and Prevotella melaninogenica were associated with
88 Review of Literature tongue samples. On the other hand, most of the Gram-negative taxa detected more frequently from subgingival samples, included Treponema species, T. forsythia, Porphyromonas endodontalis, A. actinomycetemcomitans, Prevotellaoris, Dialisterinvisus, and Fusobacterium nucleatum while subgingivally associated Gram- positive species included Streptococcus mutans, Streptococcus sanguinis, Streptococcus anginosus, Actinomyces naeslundii II, Actinomyces gerencseriae, and Filifactoralocis Fusobacterium nucleatum subsp. Polymorphum and Prevotella denticola subgingivally was associated with detection on the tongue.
Porphyromonas gingivalis was detected in less than 5% of samples when DNA probes used. Treponema denticola, Bacteroidetes, Fusobacterium nucleatum subsp.animalis, and Fusobacterium nucleatum subsp. polymorphum, were detected more frequently in early periodontitis than in health.
The Role of Aggregatibacter actinomycetemcomitans in Periodontitis Bacterium actinomycetemcomitans was described by Klinger (1912) as cocco-bacillary bacteria isolated together with Actinomyces from actinomycotic lesions of man. It was reclassified as Actinobacillus actinomycetemcomitans by Topley and Wilson (1929) and as Haemophilus actinomycetemcomitans by Potts et al. (1985). Actinobacillus actinomycetemcomitans was transfered to a new genus Aggregatibacter gen. nov. as Aggregatibacter actinomycetem
89 Review of Literature comitans comb. to include V factor-dependent and V factor independent isolates (Lauritsen and Kilian, 2006).
Aggregatibacter actinomycetemcomitans previously Actinobacillus actinomycetemcomitans, is of spherical, oval or rod shape. Bacilar form is the most frequent; also, they could appear in coccid form, which looks like the Morse code. This microorganism is associated with different human infections, including endocarditis infectious, brain abscess and hard form of periodontal disease.
The bacterium has been identified on the sub gingival plaques of the patients with periodontitis among the youth of the patients with RPP and adult periodontitis. Also, it has been proved that the bacterium has a special role in relation to the extra mouth cavity infections (Lopez et al., 2000; Tan et al., 2001).
Actinobacillus actinomycetemcomitans is one of these bacteria causing the local periodontitis that occur especially in the youth and the progressive periodontitis in adults .This organism possesses a large number of virulence factors with a wide range of activities which enable it to colonise the oral cavity, invade periodontal tissues, evade host defences, initiate connective tissue destruction and interfere with tissue repair (Kafilzadeh et al., 2010).
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Actinobacillus actinomycetemcomitans endotoxin has the potential to modulate the host responses and contribute to tissue destruction (Wilson and Henderson, 1995).
The ability of Actinobacillus actinomycetemcomitans lipo-polysacharides to stimulate macrophages to release interleukins IL-1, IL-1β, and tumor necrosis factor (TNF) is of main importance. These cytokines are able to stimulate the bone resorption (Kesić et al., 2009).
Campos et al. (2002) studied 50 samples of patients with periodontitis and isolated 90 and 80% of the A.actinomycetemcomitans bacterium through PCR and culture method . On the other hand, Genco et al. ( 1994); Zambon et al. (1983) and Socransky et al. (1992) isolated rates of 50 to 95% of the bacterium from the affected adult individuals with periodontitus.
Yano-Higuchi et al. (2000); Sakurai et al. (2007) and Wu et al. (2007) showed that, there was a significant relationship between colonization of the A.actinomycetemcomitans bacterium and the pocket depth, so that the isolation rate of the bacterium is higher in those individuals having the pocket depth >5 mm. These findings are consistent with the anaerobic nature of the bacterium
91 Subjects And Methods
SUBJECTS AND METHODS
92 Subjects And Methods
SUBJECTS AND METHODS
Subjects Selection Criteria 1- Subjects working in the field of radiation (Group I) in occupency area (Gamma irradiation Hall in NCRRT) under protective measures using pocket dosimeters (Stephen), film badges (Horwell UK with Kodak personal monitoring film type 2) in addition to Survey meters (Ludlume, Eberline and ND-3000).
2- Exposed to low dose of radiation (0.01mSv of Gamma radiation 20 minutes daily, 5 days a week) Table (1), Figure (5)
3- Male subjects with age range (25- 45)
4- Apparently healthy and not suffering from any systemic diseases as evaluated by Cornell Index (Kerr and Millarad, 1965) and by the modified Cornell medical index (Brightman, 1994).
Exclusion Criteria:
1- Workers on antibiotic, anti-inflammatory or anti-coagulant therapy.
2- Workers with history of diabetes, hepatic diseases or any immunological diseases.
93 Subjects And Methods
3- Workers with history of salivary gland surgery or any medications intake that affect the salivary flow
4- Workers with history of any motor disorders that affect the salivary flow
5- Workers with history of smoking and / or alcohol intake.
Subjects are divided into two groups; group I (study groups) workers in radiation field which is subdivided into three subgroups according to exposure time and group II (control group) working apart from the radiation field:
Group I (study groups) Group (a): Twenty workers in radiation field for at least 10 years Group (b): Twenty workers in radiation field form 5-10 years Group (c): Twenty workers in the radiation for at least 5 years
Group II (control):
Twenty workers that are not working in the field of radiation.
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Table (1): Collective Dose Equivalent for NCRRT Radiation Workers during 2005 – 2010
No. of Annual collective Average Annual Year monitored dose equivalent personal dose workers (Man-mSv) equivalent mSv/y 2006 53 24.79 0.47 2007 54 53.58 1 2008 61 52.81 0.87 2009 65 56.2 0.9 2010 61 81 1.3
It may be pointed out from this table that the higher average annual personal dose equivalent at NCRRT over the last five years is about 1.3 mSv/y which represent a small fraction of the annual dose limit (about 6.5 %).
95 Subjects And Methods
Figure (2): Mean distribution of occupational workers with annual dose interval during 2010.
Methods of assessments Immunological assessment Saliva analysis was performed for each of the four groups to determine the levels of SIgA Collection of saliva samples Samples were collected at least 2 hours after the last meal. Workers were asked to rinse their mouth thoroughly with water 10 minutes before the sample collection. The collection of unstimulated saliva was determined under resting conditions. Subjects were asked to sit passively and expectorate into pre weighed plastic containers for 5 minutes as saliva accumulated in the mouth.
96 Subjects And Methods
Samples were collected on ice over 5 minutes period, stored at 4oC to avoid bacterial contamination and transfered in the icebox to laboratory for SIgA measurment
The collected samples were centrifuged individually at 4000 RPM for 10 minutes, then the levels of SIgA were determined using immunoturbidimetric method (SpinReact, SA, Gerona, Spain).
The Spin React kit contains two reagents R 1 and R2. R 1 contains tris buffer 20 mol/L, PEG 8000, sodium azide 0.95 g/L, pH 8.2. R 2 contains goat serum, antihuman IgA, Sodium azide 0.95 g/L, pH 7.5.
The procedure was as follows: 950 µl of R 1 was dispensed into the test tube to which 7 µl of the sample was added. Both were mixed and the absorbance reading was taken as A 1. Later,
50 µl of R 2 was added and the absorbance reading A2 was taken after one minute. The values were substituted using the following
A2 -A1= A ΔA x factor = IgA level Where, factor is (calibrator concentration) / (ΔA of the calibrator) equaling 1736. Thus, the quantity of IgA in each sample was calculated.
97 Subjects And Methods
Microbiological assessment Paperpoint sampling procedure The site to be tested was cleaned of all supragingival plaque and then thoroughly dried. Three paperpoint strip of moderate strength was aseptically inserted into the deepest periodontal pockets of the subject for 10 sec. The strip was removed with care not to contact with saliva, pus or the oral mucosa. The paperpoint was then placed into anaerobic dental transport medium and transported to the laboratory for microbial analysis (Jervoe et al., 2007).
Paperpoint processing The specimens were immersed in 5 ml reduced transport fluid (Thioglycolate Broth), dispersed by vortexing (Autovortex Mixer SA2, Stuart Scientific, London, UK) at maximum setting for 30 s. Aliquots 0f the dispersed microbial suspension was serially diluted and 0.1 ml was inoculated on the agar media.
Isolation of anaerobic bacteria For isolation of anaerobic bacteria, subculture was made from Thioglycolate broth onto Columbia Blood Agar Base, Brucella agar, Brain heart infusion agar and Chocolate agar. All plates were incubated with 5% CO2 for at least 5 days. After incubation, plates with colonies that were well separated and evenly dispersed were selected.
98 Subjects And Methods
Selective culture of aerobic and facultative anaerobic Gram-negative rods and yeasts The dispersed microbial suspension was inoculated by spiral plating onto duplicated MacConkey agar (Oxoid, Hampshire, UK) plates and incubated for 18 h at 37oC. Eighteen Cultures were examined; the aerobic and facultative anaerobic Gram-negative rod and yeast colonies were subcultured on their respective culture media to obtain pure isolates.
Identification of isolates Isolates were identified presumptively using colony morphology, haemolysis, pigmentation, cell morphology, catalase and oxidase tests and the ability to grow in air supplemented with 10% CO2.
Materials 1- 1- Media 1- 1- a- Columbia Blood Agar (g/l) Peptone 23 Starch 1.0 NaCl 5.0 Agar agar 20 pH 7.3 1- 1- b- Brain Heart Infusion (g/l) Brain heart-infusion 6.0 g Peptic digest of animal tissue 6.0 g
99 Subjects And Methods
NaCl 5.0 g Dextrose 3.0 g Pancreatic digest of gelatin 14.5 g
Na2HPO4** 2.5 g Agar agar 20 Final pH, 7.4 ± 0.2.
Heat to dissolve agar before dispensing into bottles or flasks. Autoclave 15 min at 121°C. 1- 1- c- Brucella Agar (g/l) Peptone 10.0 Lab lemeco 5.0 Glucose 10 NaCl 5.0 Agar agar 20
1- 1- d- MacConkey Agar (g/l) Proteose peptone 3 g Peptone 17 g Lactose 10 g Bile salts 1.5 g NaCl 5 g Neutral red 0.03 g Crystal violet 0.001 g Agar 13.5 g Final pH, 7.1 ± 0.2.
100 Subjects And Methods
Suspend ingredients and heat with agitation to dissolve. Boil 1-2 min. Autoclave 15 min at 121°C, cool to 45- 50°C, and pour 20 ml portions into sterile 15 x 100 mm petri dishes. Dry at room temperature with lids closed.
1- 1- e- Trypticase (Tryptic) Soy Agar (g/l) Trypticase peptone 15 g Phytone peptone 5 g NaCl 5 g Agar 15 g
Final pH, 7.3 ± 0.2.
Heat with agitation to dissolve agar. Boil 1 min. Dispense into suitable tubes or flasks. Autoclave 15 min at 121°C.
1- 1- f- Blood Agar (g/l) Tryptone 15 g Phytone or soytone 5 g NaCl 5 g Agar 15 g Final pH of base, 7.3 ± 0.2.
Heat with agitation to dissolve agar. Autoclave 15 min at 121°C. Cool to 50°C. Add 5 ml defibrinated sheep red blood cells to 100 ml melted agar. Mix and pour 20 ml portions into sterile 15 x 100 mm petri dishes.
101 Subjects And Methods
1- 1- g- Thioglycollate Medium (g/l) L-Cystine 0.5 g Agar (granulated) 0.75 g NaCl 2.5 g Dextrose 5 g Yeast extract 5 g Tryptone 15 g Sodium thioglycollate 0.5 g Resazurin, sodium solution (1:1000), fresh 1 ml
Mix L-cystine, NaCl, dextrose, yeast extract, and tryptone with 1 liter water. Heat in Arnold steamer or water bath until ingredients are dissolved. Dissolve sodium thioglycollate or thioglycollic acid in solution and adjust pH so that value after sterilization is 7.1 ± 0.2. Add sodium resazurin solution, mix, and autoclave 20 min at 121°C. If commercial media are used, dispense 10 ml portions to 16 x 150 mm tubes and autoclave 15 min at 121°C.
1- 1- h- Motility Test Medium (Semisolid) Beef extract 3 g Peptone or gelysate 10 g NaCl 5 g Agar 4 g Final pH, 7.4 ± 0.2.
102 Subjects And Methods
Heat with agitation and boil 1-2 min to dissolve agar. Dispense 8 ml portions into 16 x 150 screw-cap tubes. Autoclave 15 min at 121°c
Dental Assessment
1- The Decayed-Missed -Filled Index (DMF)
Decayed Missed Filled Index is an irreversible index, which measures the total life time caries experience. It is introduced by (Klein et al., 1938).
Instruments used in the examination are: mouth mirror, explorer or a CPI probe (WHO, 1997).
All the teeth in the oral cavity are examined except: 1- Supernumerary teeth/ unerupted teeth/ congenitally missing teeth. 2- Extracted teeth or lost teeth for reasons other than caries. 3- Restored teeth for reasons other than caries. 4- Third molars.
All decayed missed and filled components are added separately to get the DMF score for each patient. Values of Permanent and deciduous teeth should be kept separate
103 Subjects And Methods
2- Periodontal Index (PI)
PI determines the periodontal disease status of populations in the study.
Each tooth is scored according of the surrounding tissues. On examination, each tooth is assigned a score using the periodontal index of Ramfjord 0 negative 1 mild gingivitis 2 moderate gingivitis 3 Severe gingivitis periodontitis 4 periodontal pocket 3mm apically 5 Pathological pocket 3-6 mm.
6 Pathological pocket of 6 mm or more.
3- Plaque Index (PLI) It is an assessment tool used to evaluate the thickness of plaque at the gingival margin that may be applied to the selected teeth or to the entire oral cavity.
104 Subjects And Methods
Quigley Hein Index (HQI), 1962 is used to score the plague according to the following criteria:
0 No plaque 1 Isolated flecks of plaque near the gum margin. 2 1 mm band of plaque and the gingival margin 3 Up to 1/3 of surface covered with plaque. 4 Disclosed plaque 1/3 to 2/3 of the surface. 5 Disclosed plaque more than 2/3 of the surface.
Statistical Analysis
All analysis were performed in SPSS version 10.01 soft were (SPSS, Inc., Chicago, IL, USA) .Parameters among control and study groups were compared using Chi square test for determination of presence and absence of bacteria and Candida albicans, Anova test for comparison secretary IgA and Dental indices and T test for comparison between each two groups of the study.
105 Results RESULTS
106 Results
RESULTS
The Microbiological assessment
elective cultures of aerobic and anaerobic bacteria as well Sas Candida were made. Isolates identified were; Aggregatibacter actinmycetemcomitans Fusobacterium, Bacteriod forythus, Sterptococcus mutans, Staphylococcus aureus, Pseudomonas aeroginosa, E.coli and Candida albicans Figures (3,4,5,6, 7,8,9,10).
Figure (3-a): Aggregatibacter actinmycetemcomitans on Brain Heart Infusion supplemented with 5% sheep blood and 5% serum.
107 Results
Figure (3-b): Gram stain of Aggregatibacter actinmycetemcomitans under light microscope.
Figure (4a): Colonies of Fusobacterium on TSA supplementd with 5% sheep blood and5% serum.
108 Results
Figure (4-b) Gram stain of Fusobacterium under light microscope
Figure (5a): Colonies of Bacteroid forythus on Brucella agar supplemented with8% sheep blood and 5% serum.
109 Results
Figure (5-b): Gram stain of Bacteroid forythus under light microscope
Figure (6a): Colonies of Streptococcus mutans on MacConkey agar
110 Results
Figure (6-b) Gram stain of Streptococcus mutans under light microscope
Figure (7a): Colonies of Staphylococcus aureus on Blood agar
111 Results
Figure (7-b) Gram stain of Staphylococcus aureus under light microscope.
Figure (8a): Colonies of Pseudomanas aerogonsa
112 Results
Figure (8-b) Gram stain of Pseudomonas aeroginosa under light microscope.
Figure (9-a): Colonies of E. coli on (Luria Bertani agar)
113 Results
Figure (9-b) Gram stain of E.coli under light microscope
Figure (10): Colonies of Candida albicans on MacConkey agar
The presence and the absence and the significance of different types of bacteria and Candida albicans within the study groups and the controls were statistically determined using Chi - Square test and their results were as follows:
114 Results
Table (2): Comparison between groups concerning Aggregatibacter actinomycetemcomitans
Groups Absence of Bacteria Presence of Bacteria 1st group 11 9 18.9% 40% 2nd group 13 7 22.4% 31.8% 3rdgroup 14 6 24.13% 27.2% 4th group 20 0 (control) 34.4% 0%
First group: workers in radiation field for at least 10 years Second group: workers in radiation from 5-10 years Third group: workers in radiation for at least5 years Fourth group (controls): workers away from the radiation field X2 = 11.285 P= 0.010
There is a significant difference between the study groups and the controls groups concerning the presence and absence of Aggregatibacter actionomycetemcomitans p=(0.010), Fusobacterium p = (0.012) and Bacteriod p= (0.02). Tables (2, 3, 4), Figures (11, 12, 13).
115 Results
Table (3): Comparison between groups concerning Fusobacterium
Groups Absence of Bacteria Presence of Bacteria
1st group 12 8 20.33% 38.9% 2nd group 12 8 20.33% 38.9% 3rdgroup 15 5 25.4% 23.8% 4th group 20 0 (control) 33.8% 0% X2 = 11.04 P = 0.012
Table (4): Comparison between the four groups concerning Bacteriod
Groups Absence of Bacteria Presence of Bacteria
1st group 9 11 16.9% 40.7% 2nd group 10 10 18.8% 37% 3rdgroup 15 5 28.3% 18.5% 4th group 19 1 (control) 35.8% 3.7% X2 = 14.47 P = 0.002
116 Results
Distribution of Actinomycetem among studied groups
20 18 16 14 12 Number of 10 subje cts N0 8 Yes 6 4 2 0 First Second Third Fourth Groups
Figure (11): Distribution of Aggregatibacter actinomycetem comitans among studied groups
Distribution of Fusio bacterium among studied groups
20 18 16 14 12 Subjects 10 No 8 Yes 6 4 2 0 First Second Third Fourth Groups
Figure (12): Distribution of Fusiobacterium among studied groups
117 Results
Distribution of Bacteroid among studied groups
20
15
Number of subjects 10
5
0 First Second Third Fourth Groups
No Yes
Figure (13): Distribution of Bacteriod among studied groups
There is no significant difference between the study groups and controls concerning the presence and absence of Streptococus mutans p = (0.14), Staphyloccocus aureus p = (0.196), Pseudomanas aerogonsa p = (0. 825), E.coli p = (0.568) and Candida albicans p = (o.606). Tables (5, 6, 7, 8, 9), Figures, (14, 15, 16, 17, 18).
Table (5): Comparison between groups concerning Streptococcus mutans Groups Absence of Bacteria Presence of Bacteria 7 13 1st group 17% 33.3% 9 11 2nd group 21.9% 28.2% 11 9 3rdgroup 26.8% 23% 4th group 14 6 (control) 34.1% 15.3% X 2 = 5.3. P = 0. 14
118 Results
Table (6): Comparison between groups concerning Staphyloccocus auries Groups Absence of Bacteria Presence of Bacteria 5 15 1st group 15.15% 31.9% 10 10 2nd group 30.3% 21.2% 11 9 3rdgroup 33.3% 52.9% 4th group 7 13 (control) 21.2% 27.6% X2 = 4.694 P= 0.196
Table (7): Comparison between groups concerning Pseudomanas aerogonsa Groups Absence of Bacteria Presence of Bacteria 15 5 1st group 23% 33.3% 16 4 2nd group 24.6% 26.6% 17 3 3rdgroup 26.15% 20% 4th group 17 3 (control) 26.15% 20% X2 = 0.903 P= 0.825
119 Results
Table (8): Comparison between groups concerning E.coli
Groups Absence of Bacteria Presence of Bacteria 15 5 1st group 30.6% 16.6% 11 8 2nd group 22.4% 26.6% 12 8 3rdgroup 24.4% 26.6% 11 9 4th group (control) 22.4% 30% X2 = 2.021 P= 0.568
Table (9): Comparison between groups concerning Candida albicans Groups Absence of Bacteria Presence of Bacteria 1st group 10 10 21.7% 29.4% 2nd group 11 9 23.9% 26.4% 3rdgroup 11 9 23.9% 26.4% 4th group 14 6 (control) 30.4% 17.64% X2 = 1.841 P= 0.606
120 Results
Table (10): Comparisons and Significance of different types of Bacteria and Candida albicans Chi square Significance Bacteria valueX 2 (P) Streptococcus mutans 0.027 0.999 Aggregatibacter actinomycetemcomitans 11.28 0.010 Fusobacterium 11.04 0.012 Bacteriod 14.47 0.002 Candida albicans 1.841 0.606 E. coli 2.021 0.568 Staphylococcus. auries 4.694 0.196 Pseudomanas aerogonsa 0.903 0.825
Distribution of Streptococcus mutans among studied groups
14
s t 12
c
e j 10
ub
s
8
f
o
r 6
e
b 4
m u 2
N 0 First Second Third Fourth Groups
N0 Yes
Figure (14): Distribution of Streptococcus mutans among studied groups.
121 Results
Distribution of Staphylococcus aureus among studied groups
16 14 12 10 8 No 6 subjects Yes Number of of Number 4 2 0 First Second Third Fourth Group
Figure (15): Distribution of Staphylococcus auries among studied groups.
Distribution of Psudomonas aeruginosa among studied groups
20
15
10 No subjects
Numberof Numberof 5 Yes 0 First Second Third Fourth Group
Figure (16): Distribution of Pseudomonas aeruginosa among studied groups.
122 Results
Distribution of E coli among studied groups
16 14 12 10 8 6 No 4 Yes 2 Number of subjects of Number 0 First Second Third Fourth Group
Figure (17): Distribution of E.coli among studied groups.
Distribution of Candida among studied groups
14 12 10 Number of 8 subj e cts 6 4 2 0 First Second Third Fourth Groups
No Yes
Figure (18):Distribution of Candida albicans among studied groups.
123 Results
The Dental assessment
Difference between the four groups concerning Dental indices: (DMF score, Periodontal index, Plaque index) and their significance were determined statistically using Anova Test and the results were as follows:
• There is a significant difference between the four groups concerning
• DMF score p =(0.000) Table (11), Figure (19)
• There is a significant difference between the four groups concerning Periodontal index p = 0.000) Table (11), Figure (20)
• There is a significant difference between the four groups concerning Plaque index p = (0.000) Table (11), Figure (21)
Table (11): Comparison between groups concerning Dental Indices using Anova Test
Variable (F) (P) DMF score 14.521 0.000 Periodontal index 113.675 0.000 Plaque index 69.619 0.000
124 Results
10 8 6 4
DMF Score 2 0 First Second Third Fourth Groups
Figure (19): Relation between the four groups concerning the DMF score.
4
3
2 Index 1 Periodontal 0 First Second Third Fourth Groups
Figure (20): Relation between the four groups and concerning the periodontal index.
125 Results
4
3
2
1 Plaque Index 0 First Second Third Fourth Groups
Figure (21): Relation between the four groups concerning of the Plaque index.
The Immunological assessment: This was done via the estimation of secretary IA levels in the four groups and determining the significant difference between them.
A significant difference between the four groups concerning Secretory IgA, p = (0.000) was detected. Table (12), Figure (22).
Table (12) Comparisons between groups concerning Secretary IgA
Variable (F) (P)
Secretary IgA 61.223 0.000
126 Results
60
50
40 30
20 Secretoy IgA Secretoy 10
0 F S T F i e h o rs c ir u t on d rth d groups
Figure (22): Relation between the four groups concerning secretary IgA.
Correlation between Dental indices and Secretary IgA Correlation between Dental indices; DMF score, Periodontal index, Plaque index and secretary IgA were statistically studied and the results were as follows: • There is a significant negative correlation between DMF score secretary IgA p = (0.001) r = -0.87, Table (13) • There is a significant negative correlation between Periodontal index and secretary IgA p = (0.001 ) r = -0.93, Table (13) • There is a significant negative correlation between Plaque index and secretary IgA p = (0.001) r = - 0.89, Table (13)
127 Results
Table (12): Correlations between DMF, Plaque index, periodontal index and Secretary IgA
Secretary IgA Variables r P DMF score -0.87 0.001 Plaque index -0.89 0.001 Periodontal index -0.93 0.001 r: secretary IgA valueP: Significance at 0.01 level
Comparisons between each two groups of the study;
Each two groups of the study were compared to each other concerning Dental indices (DMF score, Periodontal index and Plaque index) and Secretary Ig A using t- test and the results were as follows:
i- Relation between the first group and the fourth group(Control):
There is a significant difference between the two groups concerning Dental indices p = (0.000), Table (14).
There is a significant difference between the two groups concerning Secretory IgA p = (0.000), Table (14).
128 Results
Table (13): Comparison between the first group and the fourth group 1stgroup 4th group T- Significance Variables Standard Standard Mean Mean value (P) deviation deviation DMF score 8.70 1.658 4.95 1.395 7.742 0.000 Periodontal 3.90 0.308 0.80 0.768 16.76 0.000 index Plaque 3.90 0.447 0.65 0.587 19.69 0.000 index Secretary 28.04 4.695 54.7 4.889 17.39 0.000 IgA First group: Exposed workers for at least 10 years Fourth group: Control group
ii- Relation between the second and the fourth group (control): • There is a significant difference between the two groups concerning Dental indices p = (0.000) Table (15). • There is a significant difference between the two groups concerning Secretary IgA p = ( 0.000) Table (15). Table (14): Comparison between the Second group and Fourth group 2nd group 4th group T- Significance Variables Standard Standard Mean Mean value (P) deviation deviation DMF score 7.75 1.803 4.92 1.395 5.494 0.000 Periodontal 3.30 0.865 0.80 0.768 9.670 0.000 index Plaque 3.55 0.826 0.65 0.587 12.802 0.000 index Secretary - 35.18 6.47 54.76 4.889 0.000 IgA 10.811 Second group: group of workers in the field of from 5 to 10 years. Fourth group: Control group 129 Results
iii- Relation between the third and the fourth group (control): • There is a significant difference between the two groups concerning Dental indices p = (0.000) Table (16). • There is a significant difference between the two groups concerning Secretary IgA p = ( 0.000) Table (16).
Table (15): Comparison between Third group and Fourth group
3rd group 4th group T- Significance Variables Standard Mea Standard Mean value (P) deviation n deviation DMF score 8.00 2.656 4.95 1.395 4.545 0.000 Periodontal 3.05 0.826 0.80 0.768 8.975 0.000 index Plaque 3.45 0.605 0.65 0.587 14.855 0.000 index Secretary 3.96 8.794 54.76 4.889 -7.909 0.000 IgA Third group: workers in the field of radiation for at least 5 years Fourth group: Control group
iv- Relation between the first group and the third group: • There is a significant difference between the two groups concerning Dental indices p = (0.000), Table (17). • There is a significant difference between the two groups concerning Secretary IgA p = ( 0.000), Table (17).
130 Results
Table (16): Comparison between the First group and the Third group 1st group 3rd group Significance Variables Standard Standard T-value Mean Mean (P) deviation deviation DMF score 8.70 1.658 4.95 1.395 7.742 0.000 Periodontal 3.90 0.308 0.80 0.768 16.760 0.000 index Plaque 3.90 0.447 0.65 0.587 19.693 0.000 index Secretary 28.04 4.695 54.76 4.889 -17.390 0.000 IgA First group: workers in the field of radiation for at least 10 years Third group: workers in the field of radiation for at least 5 years
V- Relation between the second group and the third group: • There is no significant difference between the two groups concerning Dental indices (DMF score, Periodontal index, Plaque (index) p = 0.730, p = 0.356 p = 0.665, respectively, Table (18). • There is no significant difference between the two groups concerning Secretary IgA p = 0.469 Table (18)
Table (17): Comparison between the Second group and the Third group 2nd group 3rd group T- Significance Variables standard standard Mean Mean value P deviation deviation DMF score 7.75 1.803 8.00 2.656 0.348 0.730 Periodonta 3.30 0.865 3.65 0.826 0.935 0.356 l index Plaque 3.55 0.826 3.45 0.605 0.437 0.665 index Secretary 35.18 6.457 36.96 8.794 -0.732 0.469 IgA Second group: workers in the field of radiation from 5-10 Third group: workers in the field of radiation for at least 5 years
131 Discussion
DISCUSSION
DISCUSSION
onizing radiation has a negative effect on living organisms Idepending on dose of radiation and duration of exposure 132 Discussion
(Godekmerdan et al., 2004).
Throughout the years, studies recorded the damaging effects of radiation on dental, oral structures and salivary glands. However, most studies have been focused on head and neck irradiated subjects only, limited numbers of studies investigated the effect of low dose ionizing radiation.. Occupational exposure to ionizing radiation now generally falls well within the currently accepted limits, and is much lower than it was some years ago.
In particular, the limit of 20 mSv/year is seldom or never exceeded (Thierens et al., 1996). However, there is no established threshold for initiation of biologic changes as consequences of exposure to low level of radiation (Godekmerdan et al., 2004). In fact, some epidemiological studies have indicated that people occupationally exposed to ionizing radiation may show increased risk of leukemia (IARC, 2000).
Surveillance is largely based on physical control of operators (dosimetry). This method can effectively reveal any accidental overexposure, yet, it provides no information on the real long-term risk of low level exposure. Consequently despite the technologic advances in diagnostic equipments and implementation of protective measures, professionals remain at risk of the low dose radiation to which they are exposed (Maffei et al., 2002).
133 Discussion
Therefore, this study aimed investigating the effect of long term low levels of ionizing radiation on the hard and soft tissue structures in the oral cavity and oral microbiota and it was conducted on male subjects of age range from (25-45) years.
Gender and age range were specified, to control the changes that could be induced on the immune system due to age and gender (Percivals et al., 1994; Fenol et al., 2004 and Jafarzadeh et al., 2010).
Subjects are working under protective measures and are subjected to periodic checks of radiation dose. All subjects were chosen from full occupancy area of radiation, which is the nearest zone of radiation source5m from the shield of radiation source, so that they are exposed to the highest dose of radiation compared the other workers.
They were divided into four groups, three study groups and the fourth group that represent the control group working away from radiation source. The three study groups are divided according to the duration of radiation exposure to the first group (working for at least 10 years), the second group (working from 5 to 10 years) and the third group (working for at least 5 years).
All chosen individuals were not suffering from any apparent health problem or any apparent oral disease that could affect their oral condition.
134 Discussion
Oral characteristics of these subjects were investigated in three aspects; Microbiological, the Dental and Immunological aspect.
Microbiological assessment was made to determine the effects of low dose long term ionizing radiation on the oral microbiota. The investigation resulted in isolation of aerobic, anaerobic bacteria and Candida albicans. From these isolated bacteria, Actinobacillus actinomycetimcomitans, Fusobacterium, and Bacteriod were found to be significantly present within the study groups compared to the control group, Figure (11,12, 13) and Table (2,3,4 ).
Aggregatibacter actinomycetemcomitans (Actinobacillus- actinomycetemcomitans) was reported to be a very important periodontopathogen which has one of the main roles in the etiology of different forms of periodontal diseases. In addition a selected group of gram-negative anaerobic bacteria , including Fusobacterium, Bacteriod were proved to be frequently associated with periodontitis.
This was in accordance with Han et al. (2000) who observed a selected group of gram-negative anaerobic bacteria frequently associated with periodontal diseases, including Actinobacillusactinomycetemcomitans, Bacteroidesforsythus, Campylobacter curvus, Eikenellacorrodens, Fusobacteriumnu- cleatum, Porphyromonas gingivalis, and Prevotella intermedia along with oral spirochetese the most frequently isolated from
135 Discussion infected periodontal pockets and recognized as potential periodontal pathogens.
Hagewald et al. (2002) who stated that developing periodontal diseases isassociated with gram negative bacteria as Porphyromonas gingivalis, prevotella intermedia, bacteriodes for sythus and Actinobacillus actinomycetemcomitans and that Treponema denticola have been identified as asignificant proportion of active periodontopathic microbiota and pathogenic ecology.
Mombelli et al. (2002) who found that the presence or absence Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, and Campylobacter rectus could not discriminate between subjects chronic periodontitis and acute aggressive periodontitis. Acute aggressive periodontitis was considered to be the condition of interest and chronic periodontitis was considered equivalent to 'non-acute aggressive periodontitis. An additional assessment showed that the highly leukotoxic variant of Actinobacillus actinomycetemcomitans was uniquely associated with patients suffering from aggressive periodontitis. However, in a high proportion of patients diagnosed with acute aggressive periodontitis, the presence of this variant could not be detected.
Niemiec (2008) who stated that initial bacteria from healthy sites consist of predominately non motile gram positive aerobic facultative rods and cocci Gingivitis is caused by an
136 Discussion increase in gram negative rods and anaerobic species .In established periodontal diseases gram negative rods accounts for approximately 74% of the microflora and finally elevated numbers of spirochetes were found in almost all periodontal pockets and anaerobic organisms compose 90%of bacterial species in chronic periodontal diseases
Kesić et al. (2009) who the most important pathogenic microorganisms of periodontal disease are Gram negative as Aggregatibactera actinomycetemcomitans, Porphyromonas gingivalis Prevotella intermedia Bacteroides forsythus, Fusobacterium nucleatum, Capnocytophaga species, Campylobacter rectus. Also, Eubacterium spp, Pepto-streptococcus micros, Selenomonasnoxia, Spirochaetes could be isolated.
Kafilzadeh et al. (2010) who stated that, the Aggregatibacter actinomycetemcomitans. bacterium exists on dental plaques of the healthy individuals but its rate is very low and that, the rate of bacterium inpatient group with dental pockets is be higher than the prevalence rate of the bacterium in healthy group
Elamin et al. (2011) whodetected the non JP2 of Aggregatibacter actinomycetemcomitans. subgingival plaque of aggressive periodontitis cases compared to the control subjects and concluded that Aggregatibacter actinomycetem- comitans. is a useful marker of increased risk of development of aggressive periodontitis.
137 Discussion
Moreover, it was reported that radiotherapy causes hyposalivation which may affect the oral microbiota leading to a major imbalance of the ecosystem. The previously mentioned bacteria (Aggregatibacter actinomycetemcomitans., Fusoba- cterium, and Bacteriod) were isolated from microflora after radiation exposure
Leung et al. (1998), investigated the sub gingival plaque microorganisms of shallow pockets (≤5 mm) in subjects who previously received irradiation in the head and neck region for treatment of nasopharyngeal carcinoma. The findings appear to suggest that the major components of the sub gingival micro flora of shallow sites in previously head-and neck-irradiated individuals are similar to that of gingivitis sites in the normal population although they may contain bacterial or fungal species uncommon in normal subjects Under the microscope, the micro flora was found to be a complex mixture comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes. Low level of fungi was observed and mycelia were occasionally detected. The predominant cultivable microflora comprised several species of facultative and obligate anaerobic bacteria:
Gemella, Peptostreptococcus, Staphylococus, Stomatococcu, Streptococcus, Actinomyces, Eubacterium, Lactobacillus, Propionibacterium, Neisseria, Veillonella, Bacteroides, Campylobacter, Capnocytophaga, Fusobacterium, Kingella, Porphyromonas and Prevotella species. 138 Discussion
Andrews and Griffiths (2001) noted significant increase in numbers of Streptococcus mutans and Lactobacillus species at the expense of Streptococcus sangius. Furthermore, increase of Neisseria, Fusobacterium and Actinomomyces population.
Hommez et al. (2008) evaluated the microflora in root canals of necrotic teeth after radiotherapy of the head and neck region and detected mainly subspecies of Lactobacillus spp., Capnocytophaga spp., and Actinomyces spp.) and concluded that, the diversity of root canal microflora increases significantly, after head-neck radiotherapy
Meurman (2010) stated that, In a study from Sweden, Candida albicans was found in one or more sites in 54% of the subjects who had received radiotherapy to the head and neck in comparison to 15% of the controls. These patients also harbored enterococci in 38% versus none of the controls. Lactobacillus spp. was detected in 92% of the subjects and the proportion of the species was high compared with the controls. Mutants streptococci were also detected in high numbers; 31% in the patients vs. 23% in controls. On the other hand, in a study from China, mutants streptococci were not isolated in radiotherapy patients while lactobacilli, S. mitis and S. salivarius was the predominant caries-related oral bacteria following radiotherapy and added that, Bacteria in gingival pockets in head- and neck-irradiated patients have also been investigated. A comprehensive study from Hong Kong showed that the major components of sub-gingival microbiota 139 Discussion appear similar to that of gingivitis sites in the normal population although among the radiotherapy patients bacterial or fungal species uncommon in normal subjects were also detected.
These species included microorganisms such as Gemella, Peptostreptococcus, Staphylococcus, Stomatococcus, Streptococcus Actinomyces, Eubacterium, Lactobacillus, Propionibacterium, Neisseria, Veillonella, Bacteroides, Campylobacter, Capnocytophaga, Fusobacterium, Kingella, Porphyromonas and Prevotella.
Furthermore, Dental assessment recorded high significant difference between Dental indices(DMF index, the periodontal index and plaque index)within the study groups in comparison with the control group. The highest level was observed in the first group compared to the other groups since workers of that group are subjected to the longest radiation duration (at least 10 years), Figures (19, 20, 21), Table (11).
The mentioned findings suggest presence of high incidence of periodontitis among the study groups compared to control group.
Concerning the Immunological aspect, saliva samples were taken from all subjects in both the study groups and the control group. The choice of saliva analysis was due to its advantage as a distinctive diagnostic tool (Greabu et al., 2009).
140 Discussion
Saliva offers an alternative to serum as a biologic fluid that can be analyzed for diagnostic purposes. Whole saliva contains locally produced as well as serum-derived markers that have been found to be useful in the diagnosis of a variety of systemic disorders; it can be collected non-invasively, and by individuals with limited training. No special equipment is needed for collection of the fluid. The analysis of saliva is potentially valuable for children and older adults, since collection of the fluid is associated with fewer compliance problems as compared with the collection of blood. Furthermore, analysis of saliva may provide a cost effective approach for the screening of large populatirbidimetryons (Kauffman and Lamster, 2002).
Evaluation of SIgA levels in particular was made since Secretory IgA is the primary immunoglobulin bathing mucosal surfaces and is the first line of defense. Naturally occurring SIgA antibodies to many different antigens (oral, ocular and respiratory microorganisms) are present in mucosal fluid and may serve as major immunological defense against infection (Doifode and Damle, 2011). These antibodies may control the oral microbiota by reducing the adherence of bacteria to the oral mucosa and teeth (Marcotte and Lavoie, 1998). Furthermore, radiation exposure affects the level of SIgA, therefore, determination of the SIgA levels could be an aid in studying the changes in the oral characteristics that occur on the subjects of this study.
141 Discussion
The SIgA levels were determined using immunoturbidimetry. The principle of the immunoturbidimetry is that IgA antibodies when mixed with the samples containing IgA form insoluble complexes These complexes cause an absorbance in the spectrophotometer, dependent on the IgA concentration of the sample the reading in the spectrophotometer. The reading can be compared with calibrator of known IgA which was human serum in this study
Regarding this study, the level of SIgA of the study groups was lower than the control group. This was in agreement with (Marks et al., 1981). However, controversial to (Funegard et al., 1994 and Hofer et al., 2004) who reported higher level of SIgA in individuals after exposure to radiation. However, these researches investigated SIgA of individuals exposed to high dose of radiation for a short time (head and neck irradiated) in contrast to the subjects of our study that are exposed to low dose of radiation within a long time. Additionally significant negative correlation between SIgA and each of DMF index, Periodontal index and Plaque index was reported.
This was in agreement with (Cogulu et al , 2006) who found negative correlation SIgA and DMF index and (Chawada et al , 2010), who reported a significant inverse correlation was found between SIgA and the caries activity based on DMFT scores and suggested that the secretary immune system provides local immune protection against
142 Discussion cariogenic organisms in the oral environment and ultimately prevents dental caries
In contrast, Godekmerdan et al. (2004) found no dependence between SIgA and dental caries. In addition, Kaufman and Lamster (2002) reported, no significant correlation between SIgA and gingival index, plague index and pocket depth. Such correlation analyses are complicated by the high intrinsic variability in levels of secretory SIgA between individuals and within the same individual over short and long periods.
The present study was conducted on workers subjected to long term low dose of ionizing radiation. Those subjects are liable to higher risk of infection by extracellular agents. (Godekmerdan et al., 2004). In the same time, the reported lower level of SIgA is considered to be an important part of an integrated assessment of oral risk environment (Rhaskova et al., 2010) and indicated an increased susceptibility to caries and periodontal diseases (Marcotte and Lavoie, 1998 and Jafarzadeh et al., 2010).
This could be an explanation to the recorded results of the microbiological and the dental assessments as well as the negative correlation between SIgA and the dental indices investigated in this study.
143 Discussion
On the other hand, the reported contradiction from the other studies could be due to difference in radiation type, energy, intensity, dose and exposure time (Brant et al., 1999 and Magae et al., 2003). Furthermore, it may be due to different sampling methods, different criteria for patient selection, and different laboratory tests used between the studies. Moreover, the concentration of salivary immunoglobulin may change depending upon the salivary flow rate, hormonal factors, emotional states, and physical activity (Chawada et al., 2010).
144 Summary and Conclusions
SUMMARY AND CONCLUSION
145 Summary and Conclusions
SUMMARY AND CONCLUSIONS
adiation exposure has hazardous effects on human health R which depend on dose of radiation and duration of exposure. Despite there is no established threshold for initiation of biologic changes as consequence of low levels of radiation, only limited numbers of studies investigated the effect of occupational exposure to low dose long term ionizing radiation.
This study was designed to investigate the effect of low dose long term exposure on the oral characteristics of the workers in radiation field. The study was carried out on male subjects with age ranging from 25- 45 years working in National Center for Radiation Research and Technology (NCRRT) under protective measures and subjected to low dose long term of ionizing radiation.
The subjects were divided to 4 groups the first three groups represent the study groups and includes subjects working in radiation field and a fourth group which is the control group and includes subjects working away from radiation field).
Study groups were divided according to duration of working time into: First group including 20 subjects working for at least 10 years, Second group including 20 subjects
146 Summary and Conclusions working from 5-10 years and Third group including subjects working for at least 5 years. The investigation in both.
Study and Control groups was made via, immunological assessment by determination of the level of secretory immunoglobulin A (SIgA), microbiological assessment via detection of aerobic, anaerobic bacteria and Candida albicans and by dental assessment through determination of dental indices(Decayed Missed –Filled (DMF) index, periodontal index and Plague index).
The results of this study reported the following: - There is a significant difference between the study groups and the controls groups concerning the presence and absence of Aggregatibacter actinomycetemcomitans. p= (0.010), Fusobacterium p = (0.012) and Bacteriod p= (0.02). - There is no significance difference between the study groups and controls concerning the presence and absence of Streptococus Mutans p= (0.999), Staphyloccocus . auries p=(0.196), Pseudomanas aerogonsa p=(0. 825) E. Coli p=(0.568 ) and Candida Alibcans p=(o.606). - There is a significant difference between the four groups concerning, DMF score p =(0.000), Periodontal index p =(0.000), Plague index p=(0.000).
- There is There is a significant difference between the four
147 Summary and Conclusions
groups concerning Secretory IgA p =(0.000). - There is a significant negative correlation between DMF score secretary IgA p=(0.001) r= -0.87. - There is a significant negative correlation between Periodontal index and secretary IgA p=(0.001) r= -0.93. - There is a significant negative correlation between Plague index and secretary IgA p=(0.001) r= - 0.89. - There is a significant difference between the first group and the fourth group (Control) concerning Dental indices p =(0.000) and concerning Secretory IgA p=(0.000). - There is a significant difference between the second and the fourth group (control) concerning Dental indices p =(0.000) and concerning Secretary IgA p=(0.000). - There is a significant difference between the third and the fourth group (control) concerning Dental indices p =(0.000)and concerning Secretary IgA p=( 0.000). - There is a significant difference between the first and the third and the Fourth group (control) concerning Dental indices p =(0.000) and concerning Secretary IgA p=(0.000). - There is no significant difference between the second and third group concerning Dental indices; DMF score, Periodontal index, Plaque index p=0.730, p=0.437, p=0.437 respectively and concerning Secretary IgA p= -0.732.
148 Summary and Conclusions
Conclusions
Within the limits of this study, it was concluded that
1- Low dose long term ionizing radiation has a significant effect the level of SIgA.
2- Low dose long term ionizing radiation affects the presence and absence of Aggregatibacter actinomycetemcomitans, Fusobacterium and Bacteriod.
3- Low dose long term ionizing radiation has a no significant effect on the presence and absence of Streptococus mutans, Staphyloccocus auries, Pseudomanas aerogonsa, E.coli and Candida alibcans.
4- Low dose long term ionizing radiation has a significant effect Dental Indices (DMF index, Periodontal index and, Plaque index).
So according to this study workers in Gamma irradiation hall National center for radiation research and technology NCRRT subjected to low dose long term of ionizing radiation were found to be at higher risk to caries and periodontal diseases compared to the controls.
149 Recommendations
RECOMMENDATIONS
150 Recommendations
RECOMMENDATIONS
- Further studies should be made on the effects of the occupational exposure to different low doses of radiation for different durations on oral health
- Further studies should be made on the effects of the occupational exposure to different low doses of radiation using different methods of assessment
- Further studies should be made on the effects of the occupational exposure to different low doses of radiation on larger numbers of subjects
- Workers in the field of radiation should be subjected to periodic investigation for early detection of any hazards
151 References
REFERENCES
152 References
REFERENCES
Abu Shara K.A.; Ghareeb, M.A.; Zaher, S.; Mobache, R.A.; Khalif, M.C. and Saleh, S.Z. (1993): Radiotheraputic effect on oropharyngeal flora in patients with head and neck cancer. J. Larnyngol. Otol.; 107 (3): 222- 7.
Adams, G.E. (1968): Direct and indirect effects of irradiation on target molecules. Nature, 1: 219- 227.
Anderson, R.E. (1985): Radiation injury. In "Anderson’s Pathology". Anderson, R.T. and Kissine, J. M. (eds.), 8th ed. The C.V Mosby Comp. Louis 3: 268.
Almeida, P.V.; Gregio, A.T; Machado, M.A; Soares de Lima, A.A and Azevedo, L.R. (2008): Saliva composition and Function: A comprehensive Review. J. of Contemporary Dental Practice; 9 (3): 72-80.
Almstahl, A.; Wikstrцm, M. and Fagerberg-Mohlin B. (2008): Microflora in oral ecosystems in subjects with radiation induced hyposalivation. Oral diseases; 14, (6): 541– 549.
AL Naggar, A.M. (2009): Medical Radiation Biology, Al Tobgy press, Egypt, Cairo: 67-99
153 References
Al-Nawas, B. and K.A. (2006): Prospective study of the long term change of the oral flora after radiation therapy Supportive Care in Cancer 14,(3): 291-296
Andrews, N. and Griffiths, C. (2001): Dental complications of head and neck radiotherapy: part 1. Australian Dental Journal; 46 (2): 88- 94.
Bagherian, A.; Jafarzadeh, A.; Rezaeian, M.; Ahmad, S. and Rezaity, M.T. (2008): Comparsion of the salivary immunoglobulin concentration levels between children with early childhood caries and caries children. Iran J. Immunol.; 5: 217- 21.
Ballieux, R.E. (1991): Impact of mental stress on the immune response. J Clin. Periodontol, 18: 427– 430.
Barr-Angholme, M.; Dahlloem, P.E and Engstroem, G.N. (1998): Periodontal condition and salivary immunoglobulins in individuals with Down's syndrome. J. Periodental; 69: 1119- 1123.
Basu, M.K.; Glenwrighrt, H.D; Fox, F.C; and Becker, J.F (1976): Salivary IgG and IgA before and after periodontal therapy preliminary report. J. Res.; Peridont.; 11: 226- 229.
Baum, B.J.; Bodner, L.; Fox, P.C.; Izutsu, K.T. and Pizzo, P.A. (1985): Therapy induced dysfunction of salivary glands: Implications for oral health. Spec. Care Dent.; 5: 274–275. 154 References
Beighton, D.; Brailsford, S.; Samaranayake, L.P.; Brown, J.P.; Ping, X.F., Grant, D.G.; Harris, R.; Lo, C.M.; Naidoo, S.; Ramos-Gomez, F.; Soo, T.C. and Burnsid, E.G. (2004): A multi-country comparison of caries- associated microflora in demographically diverse children, Community Dental Health; 21: 96– 101
Beighton, D. (2005): The complex oral microflora of high risk individuals and groups and its role in the caries process. Community Dentistry and Oral Epidemiology; 33(4): 248– 255.
Belazi, M.; Velegraki, A.; Koussidou–Emerondi, T; Andreadis, D.; Hini, S.; Arsenis, G; Eliopoulou, C. and Antoniades, D. (2004): Oral Candida isolates in patients undergoing radiotherapy for head and neck cancer: prevalence azole susceptibility profiles and response to anti fungal treatment. Oral Microbiol., Immunology; 19 (6): 347- 51.
Bellanti, J.A. (1995): Immunology II, Asian edition, W. B. Saunders company: 117- 118.
Bergonine, J. (1911): Sur quelques formes de réactions precoces prиs des irradiations. Arch. Elect. Med. 19: 241–245.
155 References
Bethesda, M.D. (1993): Exposure to Ionizing Radiation Report. National Council on Radiation Protection.Natl. Council Radiat. Prot.; Limitation of 116.
Blackely, J. (1968): The Care of Radiation Casualties, White Friors Press, London: 11-13.
Blatt, E. (1976): Prevention for US: An ADA Bureau of safety service. J DA; 92 (3): 494- 5.
Bokor, M. (1997): Immunoglobulin A levels in saliva in patients with periodontal disease Med. Pregled; 50: 9- 11.
Bolstad, A.I.; Jensen, H.B. and Boken, V. (1996): Taxonomy, biology and periodontal aspects of Fusobacterium nucleatum. Clinical Microbiology Reviews; 9 (1): 55- 71.
Bosch, J.A.; Ring, C.; deGeus, E.J.; Veerman, E.C. and Amerongen, A.V. (2002): Stress and secretory immunity. Int. Rev. Neurobiol; 52: 213-53.
Bosch, J.A., Ring, C., de Geus, E.J., Veerman, E.C., and Amerongen A.V; Brailsford S.R.; Simons, D.; Gilbert D.; Clark D.; Ines, I.; Adams, S.E; Allison, C. and Beighton, D.D. (2001): The Predominant Aciduric Microflora of Root caries Lesions.J. D. R.; 80 (9): 1828- 1833.
156 References
Brandtzaeg, P.; Fjellangen, I. and Gjeruldsen S.T. (1970): Human Secretory immunoglobulins. Scand. J. Haem.;2 (1): 83- 89.
Brandtzaeg, P. (2007): The salivary antibodies reliably reflect both mucosal and systemic immunity, Ann. N. Y. Acad. Sci.; 1098: 288- 311.
Brandtzaeg, P. (2009): Mucosal immunity: Induction, dissemination, and effect or functions. Scand. J, Immuno., 70 (6): 505- 15.
Brant, W.E and Helms, C.A. (1999): Fundamentals of diagnostic radiology 2nd ed. New York: Lippincott, Willikins.
Brightman, V.J. (1994): Rational procedure for diagnosis and medical risk assessment. Oral Medicine 9th ed, Lippin Co. Philadelphia: 729-763
Burlage, F.R; Coppes, R.; Meertens, H.; Stokma, M.A. and Vissink A. (2001): Parotid and submandibular/ sublingual salivary flow during high dose radiotherapy. Radiother. Oncol., 61: 271-274
Burnsid, E.G. (2004): A multi-country comparison of caries associated microflora in demographically diverse children. Community Dental Health; 21: 96–101
157 References
Camling, E; Gahnberg, L. and Krasse, B. (1987): The Relationship between Ig antibodies to Streptococcus mutans antigens in human saliva and breast milk and the number of indigenous oral Streptococcus mutans;. Arch. Oral Biol., 32 (1): 21- 25.
Camling, E. and Kohler, B. (1987): Infection with the bacterium Streptococcus mutans and salivary IgA antibodies in mothers and their children Arch. Oral Biol.; 32: 817- 23.
Carton, R.S; Kummor V. and Robbins, S.L. (1994): Robbins Pathologic basis 5th ed. Philadelphia: W.B Saunders: 496.
Chawada, J.; Chaduvula, N.; Patel, H.; Jain, S. and Lala, A. (2001): Salivary SIgA and Dental Caries Salivary SIgA and Dental Caries Activity. Indian Pediatrics; 48 (17): 719- 721.
Cogulu, D.; Sabah, E.; Kutukculer, N. and Ozkinay, F. (2006): Evaluation of the relationship between caries indices and salivary secretory IgA, salivary pH, buffering capacity and flow rate in children with Down’s syndrome. Arch. Oral Biol.; 51: 23-8.
Cooper, J.; Fu, K.; Marks, J. and Silverman, S. (1995): Late effects of radiation therapy in the head and neck region Inter. J. of Radiat.Onco. Phys., 31(5): 1139- 1141.
158 References
Cortelli, J.R.; Cortelli, S.C.; Jordan, S.F.; Haraszthy, V.I. and Zambon, J.J. (2005): Prevalence of periodontal pathogens in Brazilians with aggressive or chronic periodontitis. J. Clin. Periodontal; 32: 860-866.
Dawes, C. and Oduim, O. (2004): Salivary status in patient treated from head and neck cancer. J. Can. Den. Assoc. 70 (6): 397- 400.
De Ferias, D.G. and Bezzera, A.C. (2006): Salivary antibodies, amylase and protein from children with early childhood caries. Clin. Oral Investig.; 7: 154- 7.
De Smet, K. and Contreras, R. (2005): Human antimicrobial peptides defenses, cathelicidins and histatins. Biotechnol. Let.; 27: 1337- 47.
Dodds, M.W.; Johnson, D.A. and Yeh, C.K. (2005): Health benefits of Saliva: a review. J. Den.; 33 (3): 223- 33.
Doifode, D. and Damle, S.G. (2011): Comparison of salivary IgA levels in caries free and caries active children. Int. J. Of Clinical Dental Science; 2(1): 10-13.
DoVale, C.H.; De Oliveira Fraga, L.A.; Costa, A. S., Tavares, C.A.; Martins, O.A.; De Macedo Farias, L. and Roque de Carvalho, M.A. (2004): Antiproliferative activity of Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum in peripheral blood mononuclear cells. Res. Microbiol.;155 (9): 731- 40.
159 References
Drucker, D.B.; Primrose, S.M.; Hobson, P. and Worthington, H.V. (1995): Salivary microflora and caries experience in 5-year-old children from two ethnic groups. International Journal of Pediatric Dentistry, 5, (1): 15- 22.
Ebersole, J.L.; Taubman, M.A.; Smith, D.J.; Genco, R.J. and Deirdre, E.F. (1981): Human immune responses to oral microorganisms. J. Clin. Exp. Immunal; 47: 43- 52.
Eisbruch, A.; Rhodus, N.; Rosenthal, D.; Murphy, B.; Rasch, C.; Sonis, S.; Scarantino, C. and Brizel, D. (2003): How should we measure and report radiotherapy induced xerostomia? Semin. Radiat. Oncol., 13: 226- 234.
Elamin, A.; Albandar, J.M.; Poulsen, R.W. and Bakken, A. (2011): Prevalence of Aggregatibacter actinomycete- mcomitans in Sudanese patients with aggressive periodontitis: a case control study. J. of Perio. Res.; 46 (3): 285– 291.
Eliasson, L.; Цsterberg, B.D. and Carlйn, A. (2006): Minor salivary gland secretion rates and immunoglobulin A in adults and the elderly. Eur. J. of Oral Sci.; 114 (6): 494- 99.
El-Shakankery, A.W. (1989): Study of the bone morrow Reserve power in cancer patients receiving chemo or radio therapy. Disease progression. Periodontology, 349 (1): 57- 83.
160 References
Evans, H.J. (1974): Effect of ionizing radiation on mammalian chromosome biochemical health .N.Y.D, 4: 191.
Kafilzadeh, F.; Ramez, M.; Mirnejad, R.; Masjedian, F. and Yaghoob, L. (2010): Detection of Actinobacillus actinomycetemcomitans from periodontitis and healthy individuals by culture and PCR methods. African J. of Microbiology Research; 4 (7): 538- 54.
Fenoll, C.; Muсoz, J.V.; Sanchiz, V.; Herreros, B.; Hernбndez, V. and Mнnguez, M. (2004): Unstimulated salivary flow rate, pH and buffer capacity of saliva in healthy volunteers. Rev. Esp. Enferm. Dig; 96 (11): 773- 83.
Fukui, M.; Masuda, K; Tamatani, K; Honnat, M. and Hinode, D. (2004): The preliminary Program for 52nd Annual meeting of Japanese Association for dental Research.
Funegard, U.; Franzen, L.; Ericson, T.H. and Henriksson, R. (1994): Partoid saliva composition during and after irradiation of head and neck cancer. Euro. J. of Cancer. Part B: Oral oncology; 30 (4): 230- 233.
Genco, R.J. (1994): Pharmaceuticals and periodontal diseases. J. Am. Dent. Assoc.; 125: 11- 19.
161 References
Gleeson, M.; Cripps, A.W. and Clancy, R.L. (1995): Modifiers of the human mucosal immune system. Immuno. Cell Biol., 73 (5): 397- 404.
Godekmerdan, A.; Ozden, M.; Ayar, A.; Gursu, F.; Ozan, T. and Serhatlioglu, S. (2004): Diminished cellular and humoral immunity in workers occupationally exposed to low levels of ionizing radiation. Archives of Medical research; 35, (4): 324- 328.
Goulhen, F., Grenieran, D. and Mayrand, D. (2003): Expression of Gro EL and Dna K Proteins during the Acquisition of a Transitory Resistance to Lethal Stresses by Actinobacillus actinomycetemcomitans Microbiological Ecology in health and disease; 15 (2-3): 120-125.
Graaff, J.D.; Winkelhoff, A.J and Goene, R.J. (1985): The role of Actinobacillus actinomycetumcomitans in human periodontal disease. Infection, 17(4): 269-271.
Greabu, M.; Mohora, M.; Totan, A.; Didilescupinu, T.; Totan, C.; Miricescu, D.Gregary, L.; Kim, D.E.; Kindle, J.C.; Hobbs, L. and Llayd, D.R. (1992): Immunoglobulin degrading enzyme in Localized juvenile periodontitis, J. of peridont. Res.; 27 (3):176- 183.
Greabu, M.; Battino M.; Mohora, M.; Totan, A; Didilescu, A., Spinu,T.; Totanin, C.; Miricesu, D. and Radulescu, R. (2009): Saliva a diagnostic window to the body, both in health and disease. J. Med. Life; 2 (2): 124- 32.
162 References
Gregory, R.L.; Kindle, J.C.; Hobbs, L.C.; Filler, S.J. and Malmstrom H.S. (1990): Function of anti-Streptococcus mutans antibodies: Inhibition of virulence factors and enzyme neutralization. Oral Microbial Immunol.; 5: 181- 188.
Greogory, R.L.; Hobbs, L.C.; Kindle, J.C; Vanto, T.O. and Maimstrom, H.S. (1990): Immuno dominant antigens of Streptococcus mutans in dental caries resistant subject. Hum. Antibodies Hybridomas; 1: 132- 136.
Grundmann, O.; Fillinger, J.; Victory, K.; Burd, R. and Limesand, K. (2010): Restoration of radiation therapy induced salivary gland dysfunction in mice by post therapy IGF-1 administration. BMC Cancer; 10 (417): 1- 9
Hagewald, S.; Bernimoulin, J.P; Kotrgen, E and Kage, A. (2000): Total IgA and Porphyromonas gingivalis reactive IgA in the saliva of patients with generalized early onset periodontitis. Clin. Oral Invest. ; 4:21-22.
Hagewald, S.; Bernimoulin, J.P.; Kotrgen, E. and Kage, A. (2002): Salivary IgA subclasses and bacteria reactive IgA in patients with aggressive periodontitis .J. Periodont. Res., 37: 333- 339.
163 References
Hagewald, S.; Fishel, D.L.; Christian, C.E.; Bernimoulin, J.P. and Kage, A. (2003): Salivary IgA in response to periodontal treatment. Euro. J. of Oral Science; 111 (3): 203- 208.
Han, Y.; Shi, W.; Georg, S.; Huang, G.; Haake, S.; Kuramitsu, H. and Genco, R. (2000): Interactions between Periodontal Bacteria and Human Oral Epithelial Cells: Fusobacterium nucleatum Adheres to and Invades Epithelial Cells. Infection and Immunity, 168 (6): 3140- 3146.
Harding, J; Berry, W.C; Marsh, C. and Jolliff, C.R. (1980): Salivary antibodies in acute gingivitis. J. Periodontal; 51: 63- 69.
Harrison, L.B.; Zelefsky, M.J.; Pfister, D.G.; Carper, E.; Rabeni, A.; Kraus, D.H., Strong, E.W.; Rao, A.; Thaler, H.; Polyak, T. and Portenoy, H. (1997): Detailed quality of life assessment in patients treated with primary radiotherapy for squamous cell cancer of the base of the tongue. Head Neck, 19: 169- 175.
Heramia, P.L. (2002): Salivary Markers of Systemic Disease: Noninvasive Diagnosis of Disease and Monitoring of General Health. J. Can. Dent Assoc.; 48: 170.
Hofer, S. (2004): Oral Microflora in patients with salivary glands hypofunctions. Oral Biosci. Med.; 2: 93- 108.
164 References
Hofer, E.; Jensen, S.; Pedersen, A.; Bardow, A. and Nauntofte, B. (2004): Oral microflora in patients with salivary glands hypofunction. Oral Biosci. Med.; 2: 93-108
Hommez, G.; Mario, R.; Claeys, V. and De Moor, R. (2008): Terminal Restriction Fragment Length Polymorphism Analysis of the Microflora in Necrotic Teeth of Patients Irradiated in the Head and Neck Region, J. of Endodontics.; 34 (9): 1048- 1051.
Humphrey, S.P. and Williamson, R.T. (2001): A review of saliva: normal composition, flow and function. J. Prosthet. Dent.; 85 (2): 162- 9.
IARAC. (2000): Monographs on the evaluation of carcinogenic risks to humans, working group on the evaluation of carcinogenic risks to humans of ionizing radiation, part I, X- and Gamma radiation and neutrons, IARAC; 75: 1- 448.
Jafarzadeh, A.; Sadeghi, G.; Karam, A. and Vazirinejad, R. (2010): Salivary IgA and IgE levels in healthy subjects: relation to age and gender. Braz. Oral. Res.; 24 (1): 21-72.
Jellema A.P.; Doornaet, P.; Slotman, B.J.; Leemans, C.R. and Langendijk, J.A. (2005): Does radiation dose to salivary glands and oral cavity predict patient related xerostomia and sticky saliva in head and neck cancer patients treated with curative radiotherapy? Radiother. Oncol.; 77(2) :164-71
165 References
Jensen, S.B.; Pedersen, A.M.; Reibel, J. and Nauntofte, B. (2003): Xerostomia and hypofunction of the salivary glands in cancer therapy. Support Care Cancer; 11: 207– 225.
Jervoe- Storm, P.M.; Alahdab, H.; Koltzscher, M.; Fimme, R. and Jepsen, S. (2007): Comparison of paper point sampling of subgingival bacteria as analyzed by real- time polymerase chain reaction. J. Periodontol, May,78 (5): 909-17.
Kafilzadeh, F.; Ramez, M.; Mirnejad, R.; Masjedian, F. and Yaghoob (2010): Detection of Actinobacillus actinomycetemcomitans from periodontitis and healthy individuals by culture and PCR methods African Journal of Microbiology Research, 4 (7): 538- 542.
Kashiima, H.K.; Kirkham W.R. and Andrews, J.R. (1965): Post-irradiation sialadentis: a study of the clinical features, histopathological changes, and serum enzyme variations following irradiation of human salivary glands. Am. J. Roentgenol Radium Ther. .Nucl. Medical, 94: 271–291.
Kauffman, E. and Lamster, B. (2002): The diagnostic application of saliva- A review. CROBM; 13 (.2): 197- 212.
166 References
Kerr, D.A. and Millard, H.D. (1965): Oral diagnosis. Mosby. Co.: 77.
Kesić, L.; Petrović, M.; Obradović, R. and Pejčić, A. (2009): The importance of Aggregatibacter actinomycete- mcomitans in etiology of periodontal disease, mini review. Acta. Medica. Medianae.; 48 (3): 35-37.
Kielbassa, A.M.; Hinkelbein, W.; Hellweig, E. and Meyer- Luckel, H. (2006): Radiation relate damage to dentition Lancet, Oncol, 7(4): 326-35
Koga, C.Y.; Mortins, C.A.; Balduca, I. and Jorge, A.O. (2004): Correlation among mutans Streptococci counts, dental caries and IgA to Streptococcus mutaus in saliva. Braz. Oral Res; 18: 350: 55.
Kolenbrander, P.E. (2000): Oral microbial communities: biofilms, interactions, and genetic systems. Annu. Rev. Microbiol.; 54: 413-437.
Kugler, J.; Hess, M. and Haake, D. (1992): Secretion of salivary immunoglobulin A in relation to age, saliva flow, mood states, secretion of albumin, cortisol, and catecholamines in saliva. J. Clin. Immunol.; 12 (1): 45- 49.
Lacatusu, S.; Franco, L. and Franco, D. (1996): Clinical and therpeutical aspects of rampiant caries in cervico-facial irradiated patients. Rev. Med. Chir. Soc. Med. Sci. Nat. Lasi., 100 (3-4): 198- 202.
167 References
Lauritsen, N.N. and Kilian, M. (2006): Reclassification of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Haemophilus paraphrophilus and Haemophilus segnis as Aggregatibacter actinomycetemcomitans gen. nov., comb. nov., Aggregatibacter aphrophilus comb. nov. and Aggregatibacter segnis comb. nov., and emended description of Aggregatibacter aphrophilus to include V factor dependent and V factor independent isolates. International Journal of Systematic and Evolutionary Microbiology, 56: 2135–2146.
Lerner, K.L and Lerner, B.W. (2003): The world of Microbiology and Immunology, Microbial Flora of the Oral Cavity, Dental Caries, Gale imprint.
Leung, W.K.; Jingl, J.; Samaranayake, L.P and Chiu, G.K. (1998): Subgingival Microbiota of shallow periodontal pockets in individuals after head and neck irradiation.Oral Microbiology and Immunology; 13(1): 1– 10.
Leung, W.K.; Dassanayake, R.S; Yau, J.Y; Jin, L.J.; Yam, W.C. and Samaranayake, L.P. (2000): Oral colonization, phenotypic and genotypic profiles of Candida species in irradiated, denate, xerostomic nasopharengeal carcinoma survivors .J. Clin. Microbiol.; 38 (6): 2219-26.
168 References
Leung, W.K.; Dassanayake,R.S.; Yau, J.Y.; Jin, L.J.; Yam, W.C. and Samaranayake, L.P. (2001): Oral colonization of aerobic and facultatively anaerobic gram negative rods and cocci in irradiated, denate, xerostomic individuals. Oral microbiology and immunology; 16 (1): 1- 9.
Llena, M.C.; Perez-Gracia, M.T.; Ferandez–Barredo, S. and Galiana, C. (2007): New culture for the isolation of Streptococcus mutans and Lactobacillus in head and neck irradiated patients. Oral health, Prev. Dent.; 5 (4): 285- 9.
Llena- Puy, C. (2006): The rфle of saliva in maintaining oral health and as an aid to diagnosis. Med. Oral Patol Oral Cir. Bucal.; 11: 449- 55.
Lopez, N.J. (2000): Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in progressive adult periodontitis. J. Periodontal, 71 (6): 948- 954.
Luhana, K.K. and Patel, H.D. (2010): Cultural and molecular characterization of tetracycline resistant micro flora associated with dental caries. International Journal of Genetics, 2 (1): 1- 7.
Maffei, F.; Angelini, S. G.; Lodi, V.; Mattioli, S. and Hrelia, P. (2002): Micronuclei frequencies in hospital workers occupationally exposed to low levels of ionizing radiation, influence of smoking status and other factors. Mutagenesis, 17 (5): 405- 409.
169 References
Magae, J.; Hoshi, Y.; Furukawa, C.; Kawakami, A. and Ogata, H. (2003): Quantitative analysis of biological response to ionizing radiation including dose, radiation time, and dose rate, 160 (5): 543- 8.
Mansheim, B.J.; Stenstrom, M.L.; Law, S.B. and Clark, W.B. (1980): Measurements of serum and salivary antibodies to oral pathogen Bacteriod asaccharalyticus in human subjects. Arch. Oral Biol.; 25: 553-557.
Marcotte, Hand Lavoie, M. (1998): Oral Microbial Ecology and the role of Salivary Immunoglobulin A. Microbiol. Mol. Biol., 62: 71- 109.
Marks, J.; Davis, C.; Gottsman, V.; Purdy, J. and Lee, F. (1981): the effect of radiation on parotid salivary function. International Journal of Radiation Oncology, 7 (8): 1013- 1019.
Mathiesen, A.T.; Ogaard, B. and Rolla, G. (1996): Oral hygiene as a variable in dental caries experience in 14- year-olds exposed to fluoride. Caries Res., 30: 29– 33.
McDermid, A.S.; McKee, A.S., Ellwood, D.C. and Marsh, P.D. (1986): The effect of lowering the pH on the composition and metabolism of a community of nine oral bacteria grown in a chemostat. J. Gen. Microbiol., 132: 1205– 1214.
170 References
Meurman, J. (2010): Oral microbiota and cancer. J. of Oral Microbiology, 2: 5195- 98.
Meyer, D.H. and Fives, P.M. (1997): The role of Actinobacillus actionomycetemcomitans in the pathogenesis of periodontal disease, Trends Microbiol., 5 (6): 224- 228.
Mombelli, A.; Casagni, F. and Madianos, P.N. (2002): Can presence or absence of periodontal pathogens distinguish between subjects with chronic and aggressive periodontitis? A systematic review. J. Clin Periodontol., 29 (3): 10-21.
Moore, W.C.; Burmeister J.A.; Brooks, C.N.; Ranney, R.R.; Hinkelmann, K.H.; Schieken, R.M., and Moore, L.H. (1993): Investigation of the influences of puberty, genetics, and environment on the composition of subgingival periodontal floras. Infect Immun., 61: 2891– 2898.
Muller, A.F. (1954): Mutations induced by radiation. Lancet, 4: 2- 1021.
Munson, M.A.; Banerjee, A.; Watson, T.F. and Wade W.G. (2004): Molecular Analysis of the Microflora Associated with Dental Caries. J. Clin. Microbiol.,;.42 (7): 3023- 3029.
171 References
Muthu, K.; Raman, R. and Gopalakrishnan, G. (2003): Oropharngeal flora changes in patients with head and neck malignancy post radiotherapy. Med. J. Malaysia, 59 (5): 585- 90.
Myint, M.M.; Steinsvoll, S.; Odden, K.; Doubloug, J. and Schenck, K. (1997): Salivary IgA response to bacteria in dental plaque as related to periodontal and HIV Infection status. Eur. J. Oral Sci., 105: 562- 570.
Nagler, R.M. (2002): The enigmatic mechanism of irradiation induced damage to the major salivary glands. Oral Diseases 8: 141–146.
Nagler, R.M. (2003): Effects of head and neck radiotherapy on major salivary glands animal studies and human implications. In vivo Athens, 17 (4): 369- 75.
Niemiec, B.A. (2008): Periodontal Disease. Topics in companion animal medicine, 23 (2): 72- 80.
Nieminen, A.; Kari, K. and Saxean, L. (1993): Specific antibodies against Actinobacillus actinoycetemcomitans in serum and saliva of patients with advanced periodontitis. Scand. J. of Dent. Res., 101: 196- 201.
Nyvad, B. and Kilian, M. (1990): Comparison of the initial streptococcal microflora on dental enamel in caries- active and in caries inactive individuals. Caries Res., 24 (4): 267- 72.
172 References
Nyvad, B. and Kilian, M. (1990): Microflora associated with experimental root surface caries in humans, Infect. Immun., 58 (6): 1628- 1633.
Ochiai, K.; Kurita-Ochiai, T.; Kamino, Y. and Ikeda, T. (1993): Effect of co-aggregation on the pathogenicity of oral bacteria. J. Med. Microbiol., 39: 183–190.
Okeson, J.P. (1998): Mangement of tempo romandibular joint and occlusion. St. Louis . Mosby.
Olsson, J. and Svanberg, M. (1991): Oral implantation in man of Streptococcus mutans in relation to salivary IgA activity. Scand. J. Dent. Res., 99: 489– 497.
Parkash, H.; Sharma, A.; Banerjee, U.; Sidhu, S.S. and Sundaram, K.R. (1994): Humoral immune response to mutans Streprocoocci associated with dental caries. Nati. Med. J. India; 7: 263- 6.
Pearce, C.; Bowde, G.H.; Evans, M.; Fitzsimmons, S.P.; Johnson, J.; Sheridan, M..J.; Wientzen, R. and Cole, M.F. (1995): Identification of pioneer viridans Streptococci in the oral cavity of human neonates. J. Med. Microbiol., 42 :67– 72.
Percival, R.S.; Challacombe, S.J. and Marsh, P.D. (1994) : Flow rates of resting whole and stimulated parotid saliva in relation to age and gender. J. Dent. Res.; 73(8):1416- 20.
173 References
Potten, C.S. (1985): Radiation and skin. Published by Taylor and Francis. 2: 54.
Prasad, K.N. (1974): Human radiation biology Churchill Livingston, London 4: 70.
Ranadheer, E.; Nayak, U.A.; Reddy, N.V. and Rao, V.A. (2011): The relationship between salivary IgA levels and dental caries in children J. Indian Soc. Pedod. Prev. Dent., 29: 106- 12.
Rankin, K.; Jones, D. and Redding, S. (2008): Oral Health in Cancer therapy. A guide for health care professionals. 3rd ed. Conference Co – Sponsors.
Rashkova, M.M.; Baleva, M.; Peneva, M. and Toneva, G. (2009): Secretory immunoglobulin (SIgA) and dental caries of children with different diseases and conditions influencing oral medium. J. of I.M.A.B.-Annual Proceeding (Scientific Papers), book, 2: 6- 9.
Reiff, R.L. (1984): Serum and Salivary IgG and IgA response to initial preparation therapy. J. Periodontol, 55: 299- 305.
Rose, P.T.; Gregory, R.L.; Gfell, L.E. and Hughes, C.V. (1994): IgA antibodies to Streptococcus mutans in caries resistant and susceptible children, 16: 272- 5.
174 References
Russell, M.W. and Rahemmtulla, M.B. (1989): Interaction between surface protein antigens of Streptococcus mutans and human salivary components. Oral Microbiol. Immunol., 4: 106–111.
Saini, S.; Aparna, M.; Gupta, N.; Mahajan, A. and Arora, D.R. (2003): Microbial flora in orodental infections .Indian Journal of Medical Microbiology, 21 (2): 111- 114.
Sakurai, K.; Wang, D.; Suzuki, J.; Umeda, M.; Nagasawa, T.; Izumi, Y., Ishikawa, I. and Isobe, M. (2007): High incidence of Actinobacillus actioycetemcomitans Infection in Acute Coronary Syndrome. Int. Heart J. 48 (6): 663- 675.
Sandohm, L. and Gronbald, E. (1984): Salivary immunoglobulins in patients with juvenile periodontitis and their healthy siblings, J. Periodontal; 55: 9- 12.
Sanhingur, S.E. and Cohen, R. (2004): Analysis of host responses and risk for Disease progression. Periodontology, 349 (1): 57- 83.
Scannapieco, F.A. (1994): Saliva bacterium interactions in oral microbial ecology. Crit. Rev. Oral. Biol. Med., 5: 203– 248.
175 References
Schenck, K.; Peoplesdorf, D.; Denis, C. and Tollefsen, T. (1993): Levels of salivary IgA antibodies reactive with bacteria from dental plague are associated with susceptibility to experimental gingivitis. J. Clin. Periodontal, 20: 411- 417.
Shao, Z.; Tang, Z.; Yan, C.; Jiang, Y.; Ma, R.; Liu, Z.U. and Huang, Z. (2011): Effects of Intensity Modulated Radiotherapy on Human Oral Microflora. J. Radiat. Res., 52: 834–839.
Shern, R.J.; Fox, P.C. and Li, S.H. (1993): Influence of age on the secretary rates of the human minor salivary glands and whole saliva. Arch. Oral. Biol., 38 (9): 755- 61.
Shifa, S.; Muthu, M.S.; Amarlal, D., Ratna, P. and Prabhu, V. (2008): Quantative assessment of IgA levels in the unstimulated whole saliva of caries free and caries active children J. Indian Soc. Pedod. Prevent Dent; 26: 158- 61.
Shugars, D.C. and Wahl, S.M. (1998): The role of the oral environment in HIV-1 transmission. J. Am. Dent. Assoc., 129: 851–858.
Slots, J. and Ting, M. (1999): Actinobacillus actinomycete- mcomitans and Porphyromonas gingivalis in human periodontal disease occurrence and treatment. Periodontol. 20: 82-121.
176 References
Smith, D.J. and Taubman, M.A. (1993): Emergence of immune competence in saliva. Crit. Rev. Oral Biol. Med., 4 (3-4): 335- 41.
Smith, D.J.; Joshipura, K.; Kent, R., and Taubman, M.A. (1992): Effect of age on immunoglobulin content and volume of human labial gland saliva. J. Dent. Res., 71(12): 1891-94.
Smith, D.J.; King, W.F. and Taubman, M.A. (1989): Isotype, subclass and molecular size of immunoglobulins in salivas from young infants. Clin. Exp. Immunol., 76 (1): 97-102.
Socransky, S.S. and Haffajee, A.D. (1992): The bacterial etiology of destructive periodontal disease; current concepts. J. Periodontol., 63 (4): 322-331.
Someya, M.; Sakata, K.; Nagakura, H.; Nakata, K.; Oouchi, A. and Hareyama, M. (2003): The Changes in Irradiated Salivary Gland Function of Patients with Head and Neck Tumors Treated with Radiotherapy. Jpn. J. Clin. Oncol., 33 (7): 336- 340.
Sonesson, M.; Hamberg, K.; Wallengren, M.L.; Matsson, L. and Ericson, D. (2011): Salivary IgA in minor-gland saliva of children, adolescents, and young adults. Eur. J. Oral Sci., 119(1): 15- 20.
177 References
Sonis, S.T. (2004): A biological approach to mucositis. J. of Support Oncology; 2 (1): 21- 32.
Sonis, S.T.; Elting, L .S. and Keefe, D. (2004): Perspectives on cancer therapy induced mucosal injury. Cancer, 100 (9): 1995-2025.
Sopha, G.B. (2006): Physics and Radiobiology of Nuclear Medicine, 3rd ed , Springer.
Staat, R.H.; Gawronsk, T.H.; Cressey, D.E.; Harris, R.S. and Folke E.A. (1975): Effects of dietary sucrose levels on the quantity and microbial composition of human dental plaque. J. Dent. Res., 54: 872–880.
Stokman, M.A.; Spijkerve, K.L.; Boezen, H.M.; Schouten, J.P., Roodenburg, J.L.N. and de Vries, E.G.E. (2006): Preventive Intervention Possibilities in Radiotherapy- and Chemotherapy-induced Oral Mucositis: Results of Meta-analyses. J. Dent. Res.; 85 (8): 690- 700.
Suntharalingam, N.; Podgorsak, E.B. and Hendry, J.H. (2006): Review of radiation oncology Physics: A Handbook for teachers and students, IAEA publication, chapter14, Basic Radiobiology, 397: 412.
Tabak, L.A. (1990): Structure and function of human salivary mucins. Crit. Rev. Oral Biol. Med., 4: 229–234.
178 References
Tahri, M.; Sohrabi, K.; Salehi, M.H. and Najafi, M.H. (2008): Clinical evaluation of the effects of radiotherapy on oral mucosa and gingival. J. of Radioth. in practice, 7: 195-204.
Tan, K.S.; Woo, C.H.; Ong, G., and Song, K.P. (2001): Prevalence of Actinobacillus actinomycetemcomitans in an ethnic adult Chinese population. J. Clin. Periodontal. 28 (9): 886- 890.
Tanner, C.R.; Paster, B.J.; Lu, C.E.; KanasiKent, R.; Van Dyke, R.T. and Sonis, S.T. (2006): Subgingival and Tongue Microbiota during early Periodontitis. J. Dent. Res., 85 (4): 318–323.
Tenovuo, J.; Lehtonen, P.; Vikari, J.; Larjava, H.; Vilja, P. and Tuorima P. (1986): Immunoglobulins and innate antimicrobial factors in whole saliva of patients with insulin-dependent diabetes mellitus. J. Dent. Res. 65: 62- 66.
Tenovuo, J.; Jentsch, H.; Soukka,T. and Karhuvaara, L. (1992): Antimicrobial factors of saliva in relation to dental caries and salivary levels of mutans Streptococci. J. Biol. Buccale, 20: 85- 90.
Thaweborn, S.; Thaweborn, B.; Nakornchai, S. and Jimaitree, S. (2008): Salivary secretory IgA, pH, How rates, mutans Streptococci and Candida in children with rampant caries. South East Asian J. Trop. Med. Public Health, 38: 893- 9.
179 References
Theerathav, J.; Srithava, J. and Thaweboon, S. (2006): Determination of oral microflora in irradiated ocular deformed children, South East Asian J. Trop. Med. Public Health, 37 (5): 991- 994.
Thierens, H.; Viral, A. and De Ridder, L. (1996): A cytogenic study of radiological workers: effect of age. Smoking and Radiation burden on the micronuclei frequency. Mutat. Res., 360: 75- 82.
Thierens, H.; Viral, A. and De Ridder, L. (1996): A cytogenic study of radiological workers: effect of age. Smoking and Radiation burden on the micronuclei frequency. Mutat. Res. 360: 75- 82.
Tolentino, E.; Centurion, B.; Helenal, L.; Ferreria, C.; De Souza, A.; Damante, J. and Bullen, I. (2011): Oral adverse effects of head and neck radiotherapy Literature review and suggestion of a clinical oral care guideline for irradiated .J. App. Oral Sci.19 (5): 1- 6.
Tong, H.C.; Gao, X.J. and Dong, X.Z. (2003): Non mutans Streptoococci in patients receiving radiotherapy in the head and neck area. Caries Res. 37 (4): 261- 6.
Van Haute, J. and Green, D.B. (1974): Relation between the conventration of bactertia in saliva and colonization of teeth in human. Infec.Immun; 9: 62-63
180 References
Van Haute, J. and Green, D.B. (1974): Relation between the conventration of bacteria in saliva and colonization of teeth in human. Infec. Immun., 9: 62- 63. Van Nieuw Amerongen, A.; Bolscher, J.G. and Veerman, E.C. (2004): Salivary proteins: protective and diagnostic value in Cariology. Caries Res., 38 (3): 247- 53. Vissink, A.; Burlage, F.R.; Spijkervet, F.K.; Jansma, J. and Coppes, R.P. (2003): Prevention and treatment of the consequences of head and neck radiotherapy. Crit. Rev. Oral Biol. Med.,14 (3):213- 25.
Walter.J. and Miller, H. (1969): A short text book of Radiotherapy. 3rd ed: Churchill living stone, London: 67-88 Wilson, M. and Henderson, B. (1995): Virulence factors of Actinobacillus actinomycetemcomitans relevant to the pathogenesis of inflammatory periodontal diseases. FEMS Microbiol. Rev. 17 (4): 365- 79.
World Health Organization (1997): Handbook for reporting results of Cancer treatment: 15- 22. Wright, W.E. (1987): Management of oral squeals. J. Dent. Res., 66: 699–702.
Wu, Y.M.; Yan, J.; Chen, L.L. and Gu, Z.Y. (2007): Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic. J. Zhejiang University Sci. B, 8 (2): 121-131.
181 References
Yang, H.W.; Asikainen, S.; Doğan, B.; Suda, R. and Lai, C.H. (2004): Relationship of Actinobacillus actinomy- cetemcomitans serotype b to aggressive periodontitis: frequency in pure cultured isolates. J. Periodontol., 75 (4): 592- 9.
Yano- Higuchi, K.; Takamatsu, N.; He, T.; Umeda, M.; and Ishikawa, I. (2000): Prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival microflora of Japanese patients with adult and rapidly progressive periodontitis. J. Clin. Periodontol., 27 (8): 597- 602.
Zambon, J.; Christersson, L.A. and Slots, J. (1983): Actinobacillus actionomycetemcomitans in human periodontal disease. Prevalence in patient groups and distribution of biotypes and serotypes within families. J. Periodontol.
Zambon, J. (1985): Actinobacillus actinomycetemcomitans in human periodontal disease J. of Clinical Periodontology, 12 (1): 1– 20.
Zelles, T.; Purushotham, K.R.; Macauley, S.P.; Oxford, G.E. and Humphreys-Beher, M.G. (1995): Saliva and growth factors: the fountain of youth resides in us all. J. Dent. Res.; 74:1826–1832
182 References
Zheng, R.; Wang, L.E.; Bondy, M.L.; WEI, Q. and Sturgis, E.M. (2004): Gamma radiation sensitivity and risk of malignant and bengin cancer, 100 (3): 561- 7.
Zuabi, O.; Machtei, E.E.; Ben-Aryeh, H.; Ardckian, L.; Peled, M. and Laufer, D. (1999): The effect of smoking and periodontal treatment on salivary composition in patients with established periodontitis, J. Periodontal, 70: 1240- 1246.
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اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻰ
اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻰ
ﻳﺘﻌﺮض اﻹﻧﺴﺎن ﻟﻤﺼﺎدر ﻣﺨﺘﻠﻔﺔ ﻣﻦ اﻹﺷﻌﺎع، وﻓﻰ اﻵوﻧﺔ اﻷﺧﻴﺮة أﺻﺒﺤﺖ اﺳ ﺘﺨﺪاﻣﺎت اﻹﺷ ﻌﺎع ﻣ ﻦ اﻟﻀ ﺮورات اﻟﻴﻮﻣﻴ ﺔ ﻣﻤ ﺎ أدى إﻟ ﻰ ازدﻳ ﺎد ﺧﻄ ﺮ اﻟﺘ ﺄﺛﻴﺮ اﻹﺷ ﻌﺎﻋﻲ ﻋﻠ ﻰ ﺻ ﺤﺔ اﻹﻧﺴ ﺎن ﺑ ﺎﻟﺮﻏﻢ ﻣ ﻦ اﺳ ﺘﺨﺪام وﺳ ﺎﺋﻞ اﻟﺤﻤﺎﻳ ﺔ اﻟﻤﺨﺘﻠﻔ ﺔ وأن ﺻﺤﺔ اﻟﻔﻢ هﻰ ﺟﺰء ﻻ ﻳﺘﺠﺰأ ﻣﻦ اﻟﺼﺤﺔ اﻟﻌﺎﻣﺔ ﻟﻺﻧﺴﺎن واﻟﺬى ﻳﺸﻜﻞ اﻹﺷﻌﺎع ﺗ ﺄﺛﻴﺮاً ﻣ ﻠ ﻤ ﻮ ﺳ ﺎً ﻋﻠﻴﻬﺎ. وﻳﺘﻌﺮض اﻟﺒﺤﺚ ﻟﺪراﺳﺔ اﻟﺘﺄﺛﻴﺮ اﻹﺷﻌﺎﻋﻲ ذو اﻟﺠﺮﻋﺔ اﻟﺼﻐﻴﺮة ﻟﻤ ﺪة زﻣﻨﻴ ﺔ ﻃﻮﻳﻠ ﺔ ﻋﻠ ﻰ ﺣﺎﻟ ﺔ اﻟﻔ ﻢ ﻟﻠﻌ ﺎﻣﻠﻴﻦ ﻓ ﻰ ﻣﺠ ﺎل اﻹﺷ ﻌﺎع وﻟﻘ ﺪ ﺷ ﺎرك ﻓ ﻰ ه ﺬا اﻟﺒﺤ ﺚ 3 ﻣﺠﻤﻮﻋ ﺎت رﺋﻴﺴ ﻴﺔ (ﻣﺠﻤﻮﻋ ﺔ اﻟﺒﺤ ﺚ) وﻣﺠﻤﻮﻋ ﺔ راﺑﻌ ﺔ (اﻟﻀ ﺎﺑﻄﺔ) وﺗﺤﺘ ﻮى ﻣﺠﻤﻮﻋﺔ اﻟﺒﺤﺚ ﻋﻠﻰ 60 ﺷﺨﺺ ﻣﻦ اﻟﻌﺎﻣﻠﻴﻦ ﻓﻰ ﻣﺠﺎل اﻹﺷ ﻌﺎع وﺗﻨﻘﺴ ﻢ ﻃﺒﻘ ﺎ ﻟﻔﺘ ﺮة اﻟﺘﻌﺮض إﻟﻰ اﻟﻤﺠﻤﻮﻋﺔ اﻷوﻟﻲ وﺗﺤﺘﻮى ﻋﻠﻰ 20 ﺷﺨﺺ وﺗﺸﻤﻞ اﻟﻌﺎﻣﻠﻴﻦ ﻓ ﻰ ﻣﺠ ﺎل اﻹﺷﻌﺎع ﻋﻠﻰ اﻷﻗﻞ 10 ﺳﻨﻮات، اﻟﻤﺠﻤﻮﻋﺔ اﻟﺜﺎﻧﻴﺔ وﺗﺤﺘﻮى ﻋﻠﻰ 20 ﺷ ﺨﺺ وﺗﺸ ﻤﻞ اﻟﻌ ﺎﻣﻠﻴﻦ ﻣ ﻦ 5-10 ﺳ ﻨﻮات واﻟﻤﺠﻤﻮﻋ ﺔ اﻟﺜﺎﻟﺜ ﺔ وﺗﺤﺘ ﻮى ﻋﻠ ﻰ 20 ﺷ ﺨﺺ وﺗﺸ ﻤﻞ اﻟﻌﺎﻣﻠﻴﻦ ﻋﻠﻰ اﻷﻗﻞ 5 ﺳﻨﻮات ،أﻣﺎ اﻟﻤﺠﻤﻮﻋ ﺔ اﻟﺮاﺑﻌ ﺔ (اﻟﻀ ﺎﺑﻄﺔ ) ﻓﻬ ﻰ ﺗﺤﺘ ﻮى ﻋﻠ ﻰ 20 ﺷﺨﺺ وﺗﺸﻤﻞ اﻟﻌﺎﻣﻠﻴﻦ ﻓﻲ ﻏﻴﺮ ﻣﺠﺎل اﻹﺷﻌﺎع آﺎﻓﺔ اﻟﻤﺠﻤﻮﻋﺎت اﺟﺮى ﻟﻬﻢ. أ- ﻗﻴﺎس ﻣﺴﺘﻮى ﺟﻠﻮﺑﻴﻦ أ ﻓﻰ اﻟﻠﻌﺎب. ب- زراﻋﺔ ﻟﻠﺒﻜﺘﻴﺮﻳﺎ اﻟﻬﻮاﺋﻴﺔ وﻻ هﻮاﺋﻴﺔ وآﺬﻟﻚ ﻓﻄﺮ اﻟﻜﻨﺪﻳﺪااﻟﺒﻴﻜﻨﺲ. ﺟـ- ﻗﻴﺎس ﻟﻤﻌﺎﻣﻞ اﻟﺘﺴﻮس، ﻟﻤﻌﺎﻣﻞ اﻟﺨﻠﺨﻠﺔ وﻣﻌﺎﻣﻞ ﺗﻜﻮﻳﻦ اﻟﺠﻴﺮ. وﻟﻘﺪ ﺗﻢ ﻣﻘﺎرﻧﺔ اﻟﻨﺘﺎﺋﺞ ﺑﻴﻦ ﻣﺠﻤﻮﻋﺔ اﻟﺒﺤﺚ (اﻟﻤﺠﻤﻮﻋﺔ اﻷوﻟﻲ ، اﻟﺜﺎﻧﻴﺔ واﻟﺜﺎﻟﺜ ﺔ ) واﻟﻤﺠﻤﻮﻋﺔ اﻟﻀﺎﺑﻄﺔ (اﻟﻤﺠﻤﻮﻋﺔ اﻟﺮاﺑﻌﺔ) .
اﻟﻤﻠﺨﺺ اﻟﻌﺮﺑﻰ
ﻧﺘﺎﺋﺞ اﻟﺪراﺳﺔ : أوﺻﺖ اﻟﻨﺘﺎﺋﺞ اﻟﺨﺎﺻﻪ ﺑﻤﺠﻤﻮﻋﺔ اﻟﺒﺤﺚ ﻣﻘﺎرﻧﺔ ﺑﺎﻟﻤﺠﻤﻮﻋﺔ اﻟﻀﺎﺑﻄﺔ : 1. ﻗﻠﺔ ﻣﺴﺘﻮي ﺟﻠﻮﻳﻦ اﻟﻤﻨﺎﻋﺔ ﻓﻲ اﻟﻠﻌﺎب ﺑﺸﻜﻞ ﻣﻠﺤﻮظ . 2. وﺟﻮد ﺑﻜﺘﺮﻳﺎ اﻻآﺘﻴﻨﻮﻣﻴﺴﻴﺘﻤﻜﻮﻣﻴﺘﺎﻧﺲ، اﻟﻔﻴﺰوﺑﻜﺘﺮﻳﻤﻮاﻟﺒﻜﺘﻴﺮوﻳﺪ ﺑﺸﻜﻞ ﻣﻠﺤﻮظ. 3. وﺟﻮد ﺗﻐﻴﺮ ﻣﻠﺤﻮظ ﻓﻲ اﻟﻤﺆﺛﺮ اﻟﺤﺴﺎﺑﻲ ﻟﻤﻌﺎﻣﻞ اﻟﺘﺴﻮﻳﺲ، ﻣﻌﺎﻣ ﻞ اﻟﺨﻠﺨﻠ ﺔ وآ ﺬﻟﻚ ﻣﻌﺎﻣﻞ ﺗﻜﻮﻳﻦ اﻟﺠﻴﺮ.
اﻻﺳﺘﻨﺘﺎﺟﺎت : ﻓﻲ إﻃﺎر اﻟﺤﺪود اﻟﺘﻲ أﺗﻴﺤﺖ ﻹﺟﺮاء اﻟﺪراﺳﺔ ﻳﻤﻜﻦ أن ﻧﺴﺘﻨﺘﺞ اﻷﺗﻲ:- - ﻳﺆﺛﺮ اﻹﺷﻌﺎع ﺑﺸﻜﻞ ﻣﻠﺤﻮظ ﻋﻠﻲ ﻣﺴﺘﻮي ﺟﻠﻮﺑﻴﻦ اﻟﻤﻨﺎﻋﺔ أ ﻓﻲ اﻟﻠﻌﺎب. - ﻳ ﺆﺛﺮ اﻹﺷ ﻌﺎع ﺑﺸ ﻜﻞ ﻣﻠﺤ ﻮظ ﻋﻠ ﻲ وﺟ ﻮد ﺑﻜﺘﺮﻳ ﺎ اﻻآﺘﻴﻨﻮﻣﻴﺴ ﻴﺘﻤﻜﻮﻣﻴﺘﺎﻧﺲ، اﻟﻔﻴﺰوﺑﻜﺘﺮﻳﻢ وآﺬﻟﻚ اﻟﺒﻜﺘﺮوﻳﺪ. - ﻳﺆﺛﺮ اﻹﺷﻌﺎع ﺑﺸﻜﻞ ﻣﻠﺤ ﻮظ ﻋﻠ ﻲ ﻣﻌﺎﻣ ﻞ ﺗﺴ ﻮس اﻷﺳ ﻨﺎن، ﻣﻌﺎﻣ ﻞ ﺧﻠﺨﻠ ﻪ اﻷﺳ ﻨﺎن وآﺬﻟﻚ ﻣﻌﺎﻣﻞ ﺗﻜﻮﻳﻦ اﻟﺠﻴﺮ. وﻣ ﻦ ه ﺬا ﻧﺴ ﺘﻨﺘﺞ أن ﺗ ﺄﺛﻴﺮ اﻹﺷ ﻌﺎع اﻷﻳ ﻮﻧﻲ ذو اﻟﺠﺮﻋ ﺔ اﻟﺼ ﻐﻴﺮة ﻟﻔﺘ ﺮة ﺗﻌ ﺮض زﻣﻨﻴ ﺔ ﻃﻮﻳﻠ ﺔ ﻳ ﺆﺛﺮ ﻋﻠ ﻲ اﻷﺟﺴ ﺎم اﻟﻤﻨﺎﻋﻴ ﺔ ﺟﻠ ﻮﻳﺒﻦ أ ﻓ ﻲ اﻟﻠﻌ ﺎب وﻣﻴﻜﺮوﺑﻴﻮﻟﻮﺟﻴﺎ اﻟﻔﻢ آﺬﻟﻚ ﻋﻠﻲ ﺗﺴﻮس وﺧﻠﺨﻠﻪ اﻷﺳﻨﺎن وﻣﻌﺎﻣﻞ ﺗﻜﻮﻳﻦ اﻟﺠﻴﺮ.
ﺻﻔﺤﺔ اﻟﻤﻮاﻓﻘﺔ ﻋﻠﻲ اﻟﺮﺳﺎﻟﺔ دراﺳﺔ ﺧﺼﺎﺋﺺ ﺣﺎﻟﺔ اﻟﻔﻢ ﻟﻠﻌﺎﻣﻠﻴﻦ ﻓﻲ ﻣﺠﺎل اﻹﺷﻌﺎع
رﺳﺎﻟﺔ ﻣﻘﺪﻣﺔ ﻣﻦ اﻟﻄﺎﻟﺒﺔ رﺿﻮي ﻋﺒﺪ اﻟﺒﺎﺳﻂ إﺑﺮاهﻴﻢ ﺳﻼم ﺑﻜﺎﻟﻮرﻳﻮس ﻃﺐ وﺟﺮاﺣﺔ اﻟﻔﻢ واﻷﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻟﻘﺎهﺮة 1993 ﻣﺎﺟﺴﺘﻴﺮ ﺗﻘﻮﻳﻢ أﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻹﺳﻜﻨﺪرﻳﺔ 2003
ﻻﺳﺘﻜﻤﺎل ﻣﺘﻄﻠﺒﺎت اﻟﺤﺼﻮل ﻋﻠﻲ درﺟﺔ دآﺘﻮراﻩ ﻓﻠﺴﻔﺔ ﻓﻲ ﻋﻠﻮم اﻟﺒﻴﺌﺔ - ﻗﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ اﻟﺒﻴﺌﻴﺔ وﻗﺪ ﺗﻤﺖ ﻣﻨﺎﻗﺸﺔ اﻟﺮﺳﺎﻟﺔ واﻟﻤﻮاﻓﻘﺔ ﻋﻠﻴﻬﺎ: اﻟﻠﺠﻨﺔ: اﻟﺘﻮﻗﻴﻊ 1- ا.د/ ﺧﺎﻟﺪ ﻋﺎﻃﻒ ﻋﺒﺪ اﻟﻐﻔﺎر أﺳﺘﺎذ ورﺋﻴﺲ ﻗﺴﻢ ﻃﺐ اﻟﻔﻢ وﻋﻼج اﻟﻠﺜﺔ ـ آﻠﻴﺔ ﻃﺐ اﻷﺳﻨﺎن ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ 2- ا.د/ ﻋﺎﻃﻒ اﻟﺸﺤﺎت ﻋﻄﻴﻪ أﺳﺘﺎذ ﻃﺐ اﻟﻔﻢ وﻋﻼج اﻟﻠﺜﺔ ـ آﻠﻴﺔ ﻃﺐ اﻷﺳﻨﺎن ﺟﺎﻣﻌﺔ اﻟﻘﺎهﺮة 3- ا.د/ ﻣﺤﻤﻮد ﺳﺮي اﻟﺒﺨﺎري أﺳﺘﺎذ ورﺋﻴﺲ ﻗﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ ـ ﻣﻌﻬﺪ اﻟﺪراﺳﺎت واﻟﺒﺤﻮث اﻟﺒﻴﺌﻴﺔ ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ 4- د./هﺎﻟﺔ إﺑﺮاهﻴﻢ ﻋﻮض اﷲ أﺳﺘﺎذ ﻣﺴﺎﻋﺪ ﺑﻘﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ اﻟﺒﻴﺌﻴﺔ ـ ﻣﻌﻬﺪ اﻟﺪراﺳﺎت واﻟﺒﺤﻮث اﻟﺒﻴﺌﻴﺔ ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ 2012
دراﺳﺔ ﺧﺼﺎﺋﺺ ﺣﺎﻟﺔ اﻟﻔﻢ ﻟﻠﻌﺎﻣﻠﻴﻦ ﻓﻲ ﻣﺠﺎل اﻹﺷﻌﺎع
رﺳﺎﻟﺔ ﻣﻘﺪﻣﺔ ﻣﻦ اﻟﻄﺎﻟﺒﺔ رﺿﻮي ﻋﺒﺪ اﻟﺒﺎﺳﻂ إﺑﺮاهﻴﻢ ﺳﻼم ﺑﻜﺎﻟﻮرﻳﻮس ﻃﺐ وﺟﺮاﺣﺔ اﻟﻔﻢ واﻷﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻟﻘﺎهﺮة 1993 ﻣﺎﺟﺴﺘﻴﺮ ﺗﻘﻮﻳﻢ أﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻹﺳﻜﻨﺪرﻳﺔ 2003
ﻻﺳﺘﻜﻤﺎل ﻣﺘﻄﻠﺒﺎت اﻟﺤﺼﻮل ﻋﻠﻲ درﺟﺔ دآﺘﻮراﻩ ﻓﻠﺴﻔﺔ ﻓﻲ ﻋﻠﻮم اﻟﺒﻴﺌﺔ - ﻗﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ اﻟﺒﻴﺌﻴﺔ ﺗﺤﺖ إﺷﺮاف: 1- ا.د/ ﺧﺎﻟﺪ ﻋﺎﻃﻒ ﻋﺒﺪ اﻟﻐﻔﺎر
أﺳﺘﺎذ ﻃﺐ اﻟﻔﻢ وﻋﻼج اﻟﻠﺜﺔ ـ آﻠﻴﺔ ﻃﺐ اﻷﺳﻨﺎن ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ 2- ا.د/ ﻋﺒﺪ اﻟﻤﻨﻌﻢ ﺳﻴﺪ ﺑﺸﻨﺪي أﺳﺘﺎذ اﻟﻤﻴﻜﺮوﺑﻴﻮﻟﻮﺟﻲ ـ اﻟﻤﺮآﺰ اﻟﻘﻮﻣﻲ ﻟﺒﺤﻮث اﻟﺘﻜﻨﻮﻟﻮﺟﻴﺎ واﻹﺷﻌﺎع 3- د./هﺎﻟﺔ إﺑﺮاهﻴﻢ ﻋﻮض اﷲ أﺳﺘﺎذ ﻣﺴﺎﻋﺪ ﺑﻘﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ اﻟﺒﻴﺌﻴﺔ ـ ﻣﻌﻬﺪ اﻟﺪراﺳﺎت واﻟﺒﺤﻮث اﻟﺒﻴﺌﻴﺔ ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ 4- د./ﻣﺤﻤﺪ ﺟﺎﺑﺮﺣﺠﺎج ﻣﺪرس ﻃﺐ اﻟﻔﻢ وﻋﻼج اﻟﻠﺜﺔ ـ اﻟﻤﺮآﺰ اﻟﻘﻮﻣﻲ ﻟﺒﺤﻮث اﻟﺘﻜﻨﻮﻟﻮﺟﻴﺎ واﻹﺷﻌﺎع
ﺧﺘﻢ اﻹﺟﺎزة أﺟﻴﺰت اﻟﺮﺳﺎﻟﺔ ﺑﺘﺎرﻳﺦ / / 2012 ﻣﻮاﻓﻘﺔ ﻣﺠﻠﺲ اﻟﻤﻌﻬﺪ ﻣﻮاﻓﻘﺔ اﻟﺠﺎﻣﻌﺔ 2012/ / 2012/ / دراﺳﺔ ﺧﺼﺎﺋﺺ ﺣﺎﻟﺔ اﻟﻔﻢ ﻟﻠﻌﺎﻣﻠﻴﻦ ﻓﻲ ﻣﺠﺎل اﻹﺷﻌﺎع
رﺳﺎﻟﺔ ﻣﻘﺪﻣﺔ ﻣﻦ اﻟﻄﺎﻟﺒﺔ رﺿﻮي ﻋﺒﺪ اﻟﺒﺎﺳﻂ إﺑﺮاهﻴﻢ ﺳﻼم ﺑﻜﺎﻟﻮرﻳﻮس ﻃﺐ وﺟﺮاﺣﺔ اﻟﻔﻢ واﻷﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻟﻘﺎهﺮة 1993 ﻣﺎﺟﺴﺘﻴﺮ ﺗﻘﻮﻳﻢ أﺳﻨﺎن ـ آﻠﻴﺔ ﻃﺐ اﻟﻔﻢ واﻷﺳﻨﺎن ـ ﺟﺎﻣﻌــﺔ اﻹﺳﻜﻨﺪرﻳﺔ 2003
اﺳﺘﻜﻤﺎل ﻣﺘﻄﻠﺒﺎت اﻟﺤﺼﻮل ﻋﻠﻲ درﺟﺔ دآﺘﻮراﻩ ﻓﻠﺴﻔﺔ ﻓﻲ ﻋﻠﻮم اﻟﺒﻴﺌﺔ
ﻻﺳﺘﻜﻤﺎل ﻣﺘﻄﻠﺒﺎت اﻟﺤﺼﻮل ﻋﻠﻲ درﺟﺔ دآﺘﻮراﻩ ﻓﻠﺴﻔﺔ ﻓﻲ ﻋﻠﻮم اﻟﺒﻴﺌﺔ
ﻗﺴﻢ اﻟﻌﻠﻮم اﻟﻄﺒﻴﺔ اﻟﺒﻴﺌﻴﺔ ﻣﻌﻬﺪ اﻟﺪراﺳﺎت واﻟﺒﺤﻮث اﻟﺒﻴﺌﻴﺔ ﺟﺎﻣﻌﺔ ﻋﻴﻦ ﺷﻤﺲ
2012
اﻟﻤﺴﺘﺨﻠﺺ
أﺳ ﺘﻬﺪف اﻟﺒﺤ ﺚ دراﺳ ﺔ ﺣﺎﻟ ﺔ اﻟﻔ ﻢ ﻟﻠﻌ ﺎﻣﻠﻴﻦ ﻓ ﻰ ﻣﺠ ﺎل اﻹﺷ ﻌﺎع ﺑ ﺎﻟﻤﺮآﺰ اﻟﻘ ﻮﻣﻰ ﻟﺒﺤ ﻮث اﻟﺘﻜﻨﻮﻟﻮﺟﻴﺎ واﻹﺷﻌﺎع واﻟﻤﺘﻌﺮﺿﻮن ﻟﺠﺮﻋﺎت ﺻﻐﻴﺮة ﻣﻦ اﻹﺷﻌﺎع ﻟﻔﺘﺮات ﻃﻮﻳﻠﺔ وذﻟ ﻚ ﻣ ﻦ ﺧ ﻼل ﺛ ﻼث ﻣﺠﻤﻮﻋ ﺎت رﺋﻴﺴ ﻴﺔ (ﻣﺠﻤﻮﻋ ﺔ اﻟﺒﺤ ﺚ) وﻣﺠﻤﻮﻋ ﺔ راﺑﻌ ﺔ (اﻟﻀ ﺎﺑﻄﺔ) وﺗﺤﺘ ﻮى(ﻣﺠﻤﻮﻋ ﺔ اﻟﺒﺤ ﺚ) ﻋﻠ ﻰ 60 ﺷ ﺨﺺ ﻣ ﻦ اﻟﻌ ﺎﻣﻠﻴﻦ ﻓ ﻲ ﻣﺠ ﺎل اﻹﺷ ﻌﺎع وﺗﻨﻘﺴ ﻢ ﻃﺒﻘ ﺎ ﻟﻔﺘ ﺮة اﻟﺘﻌ ﺮض إﻟ ﻰ اﻟﻤﺠﻤﻮﻋ ﺔ اﻷوﻟ ﻰ وﺗﺤﺘ ﻮى ﻋﻠ ﻰ 20 ﺷ ﺨﺺ وﺗﺸ ﻤﻞ اﻟﻌ ﺎﻣﻠﻴﻦ ﻓ ﻰ ﻣﺠ ﺎل اﻹﺷ ﻌﺎع ﻋﻠ ﻰ اﻷﻗ ﻞ10ﺳ ﻨﻮات ، اﻟﻤﺠﻤﻮﻋ ﺔ اﻟﺜﺎﻧﻴ ﺔ وﺗﺤﺘ ﻮى ﻋﻠ ﻰ 20 ﺷ ﺨﺺ وﺗﺸ ﻤﻞ اﻟﻌ ﺎﻣﻠﻴﻦ ﻣ ﻦ 5 إﻟ ﻰ 10 ﺳﻨﻮات واﻟﻤﺠﻤﻮﻋﺔ اﻟﺜﺎﻟﺜﺔ وﺗﺤﺘﻮى ﻋﻠﻰ 20 ﺷﺨﺺ وﺗﺸ ﻤﻞ اﻟﻌ ﺎﻣﻠﻴﻦ ﻋﻠ ﻰ اﻷﻗ ﻞ 5 ﺳ ﻨﻮات ، أﻣ ﺎ اﻟﻤﺠﻤﻮﻋﺔ اﻟﺮاﺑﻌ ﺔ (اﻟﻀﺎﺑﻄ ـﺔ ) ﻓﻬ ﻰ ﺗﺤﺘـ ـﻮى ﻋﻠ ﻰ 20 ﺷ ﺨﺺ و ﺗﺸ ﻤﻞ اﻟﻌ ﺎﻣﻠﻴﻦ ﻓ ﻲ ﻏﻴ ﺮ ﻣﺠ ﺎل اﻹﺷﻌﺎع. آﻼ اﻟﻤﺠﻤﻮﻋﺘﻴﻦ أﺟﺮي ﻟﻬﻢ ﻗﻴﺎس ﻣﺴﺘﻮى ﺟﻠﻮﺑﻴﻦ أ، زراﻋﺔ ﺑﻜﺘﻴﺮﻳ ﺎ اﻟﻬﻮاﺋﻴ ﺔ واﻟﻼهﻮاﺋﻴ ﺔ وﻓﻄﺮ اﻟﻜﻨﺪﻳﺪا اﻟﺒﻴﻜﻨﺲ وآﺬﻟﻚ ﻗﻴﺎس ﻟﻤﻌﺎﻣ ﻞ اﻟﺘﺴ ﻮس ، اﻟﺨﻠﺨﻠ ﺔ وﺗﻜ ﻮﻳﻦ اﻟﺠﻴ ﺮ . أوﺿ ﺤﺖ اﻟﻨﺘ ﺎﺋﺞ اﻟﺨﺎﺻﺔ ﺑﻤﺠﻤﻮﻋﺔ اﻟﺒﺤﺚ ﻣﻘﺎرﻧﺔ ﺑﺎﻟﻤﺠﻤﻮﻋﺔ اﻟﻀﺎﺑﻄﺔ ، ﻗﻠﺔ ﻣﺴﺘﻮى ﺟﻠﻮﺑﻴﻦ اﻟﻤﻨﺎﻋﺔ أ ﻓﻰ اﻟﻠﻌ ﺎب ، وﺟﻮد ﺑﻜﺘﺮﻳﺎ اﻷآﺘﻴﻨﻮ ﻣﻴﺴﻴﺘﻢ آﻮﻣﻴﺘﺎﻧﺲ ، اﻟﻔﻴﺰوﺑﻜﺘﺮﻳﻢ واﻟﺒﻜﺘﻴﺮوﻳﺪ وآﺬﻟﻚ وﺟﻮد ﺗﻐﻴ ﺮ ﻣﻠﺤ ﻮظ ﻓ ﻰ اﻟﻤﺆﺷ ﺮ اﻟﺤﺴ ﺎﺑﻲ ﻟﻤﻌﺎﻣ ﻞ اﻟﺴ ﻮس، ﻣﻌﺎﻣ ﻞ اﻟﺨﻠﺨﻠ ﺔ وﻣﻌﺎﻣ ﻞ ﺗﻜ ﻮﻳﻦ اﻟﺠﻴ ﺮ. ﻧﺴ ﺘﻨﺘﺞ ﻣ ﻦ ذك أن اﻟﻌﺎﻣﻠﻴﻦ ﺑﺎﻟﻤﺮآﺰ اﻟﻘﻮﻣﻰ ﻟﺒﺤﻮث اﻟﺘﻜﻨﻮﻟﻮﺟﻴﺎ واﻹﺷﻌﺎع أآﺜﺮ ﻋﺮﺿ ﺔ ﻷﻣ ﺮاض اﻟﺘﺴ ﻮس واﻟﺘﻬﺎﺑ ﺎت اﻷﻏﺸﻴﺔ اﻟﻤﺤﻴﻄﺔ ﺑﺎﻟﻠﺜﺔ وآﺬﻟﻚ ﺗﺨﻠﺨﻞ اﻷﺳﻨﺎن.