National Medical University of Lviv

DANYLO HALYTSKY NATIONAL MEDICAL UNIVERSITY OF LVIV DEPARTMENT OF THERAPEUTIC DENTISTRY

METHODOLOGICAL GUIDE for practical classes „Preclinical course of Therapeutic Dentistry” (IV semester) for the 2-nd year students Part I Lviv-2012 The methodological guide worked out by: M. Hysyk, O. Ripetska, Yu. Riznyk Edited by prof. V. Zubachyk

Accountable for an issue  first vice-rector of scientific and academicl work, professor, Corresponding Member of the Academy of Medical Sciences of Ukraine, M.R. Gzhegotskiy.

Reviewers: associate professor of department of Surgical dentistry N. Krupnik, associate professor of department of Pediatric dentistry N. Chukhraj

Methodological guide for students in Therapeutic dentistry (III semester) was discussed and approved on the sitting of the department of Therapeutic dentistry (record of proceedings №15, dated from 11, May, 2010) and approved on the meeting of Methodological committee in dentistry disciplines on June 22, 2010, protocol № 3.

Computer printing: Oksana Zamoiyska

2 CONTENT OF THE COURSE

1. Plan of the discipline „Preclinical course of Therapeutic Dentistry” according to the credit- module system of the organization of studies (CMSO) ...... 5 2. Types of self-education work for students...... 8 3. Types of individual work for students...... 9 4. The structure of discipline „Preclinical cause of Therapeutic Dentistry” estimation of grades for current educational activity (converting of traditional marks into marks, estimation in grates for implementation of individual tasks) ………... 10 5. Introduction ……………………………………. 12 6. Practical lesson 21 Filling materials. Classification. Main demands. Temporary filling materials. Composition, properties, and use indications ……………………………………… 14 7. Practical lesson 22. Bases and liners. Composition, structure, properties, and use indications ……………………………………… 19 8. Practical lesson 23. Permanent filling materials. Classification. Physical-chemical properties of cements. Indications for use …………………… 26 9. Practical lesson 24. Glass-ionomer cement. Characteristic. Indications. Peculiarities of practical use ……………………………………. 32 10. Practical lesson 25. Amalgam. Physical- chemical properties. Methods of preparation and filling with amalgams …………………………. 41 11. Practical lesson 26. Composites resins.

3 Classification. Composition. Characteristic. Indications for use. Filling materials of the main manufactures …………………………………… 50 12. Practical lesson 27. Adhesive systems for enamel and dentin ……………………………… 61 13. Practical lesson 28. Self-curing resin composites. Properties, indications for use, peculiarities of treatment ………………………. 70 14. Practical lesson 29. Light-curing resin composites. Properties, indications for use, peculiarities of treatment. Compomers ………… 74 15. Practical lesson 30. Filling of the caries cavity of the I and V classes according to Black classification. Substantiation of the choice of the filling material …………………………………. 85 16. Practical lesson 31. Filling of the caries cavity of the II class according to Black classification. Substantiation of the choice of the filling material ………………………………………… 97 17. Practical lesson 32. Filling of the caries cavity of the III and IV classes according to Black classification …………………………………… 103

4 Plans of practical lessons, out of class work and individual work in discipline „Preclinical course of Therapeutic Dentistry” for 2-rd year English-medium students (4th term) Credit-Module System

PRACTICAL LESSONS Module 2: Filling materials and Endodontics 2,2 credits (66 hours)

№ Topic Pract. Out of Individual lessons class work work 21 Filling materials. 2 1 Classification. Main demands. Temporary filling materials. Composition, properties, and use indications. 22 Bases and liners. 2 1 Review of Composition, structure, scientific properties, and use and indications. professional 23 Permanent filling 2 1 literature, materials. preparation Classification. Physical- of the chemical properties of written work cements. Indications for and carrying use. on scientific 24 Glass-ionomer cement. 2 1 investigation Types, properties, indications for use,

5 peculiarities of the filling procedure. 25 Amalgam. Physical- 2 1 chemical properties. Methods of preparation and filling with amalgams. 26 Composites resins. 2 1 Classification. Composition. Characteristic. Indications for use. Filling materials of the main manufactures. 27 Adhesive systems for 2 1 enamel and dentin. 28 Self-curing resin 2 1 composites. Properties, indications for use, peculiarities of treatment. 29 Light-curing resin 2 1 composites. Properties, indications for use, peculiarities of treatment. Compomers. 30 Filling of the caries 2 1 cavity of the I and V classes according to Black classification. Substantiation of the choice of the filling material. 31 Filling of the caries 2 1

6 cavity of the II class according to Black classification. Substantiation of the choice of the filling material. 32 Filling of the caries 2 1 cavity of the III and IV classes according to Black classification. 33 Endodontics. 2 1 Topographical anatomy of permanent teeth cavities and root canals. 34 Technique of tooth 2 1 cavity opening. Medications for pulp devitalization. Local anesthesia. 35 Endodontic instruments. 2 1 Classification. Types. Indications for use. 36 Work with endodontic 2 1 instruments. The use of medications for cleaning of the root canal. Methods of cleaning and widening of root canals. 37 Root canal filling 2 1 materials. Classification. Main demands. Partially hardening sillers.

7 Composition. Characteristic. Indications for use. 38 Filling of the root 2 1 canals with partially hardening and hardening sealers and fillers. 39 Methods of fillings of 2 1 the root canals. Mistakes and complications during endodontic manipulations, their reasons and ways of removal. 40 Summary control 2. 2 2 Summary hours 40 22

TYPES OF SELF-EDUCATION WORK FOR STUDENTS (22 hours)

№ Topic Hours Type of control 1. Preparation for the practical 15 lessons  theoretical part. 2. Individual work with the topics not included to the practical lessons : - Anatomical-physiological 1 Control at peculiarities of some parts of practical oral mucosa. lessons - Pit and Fissure sealants. 1

8 Composition. Characteristic. Indications for use. - Compomers. Composition. 1 Characteristic. Indications for use. - Topographical anatomy of 1 permanent teeth cavities and root canals. (Horizontal section. Drawing) - Topographical anatomy of 1 permanent teeth cavities and root canals. (Vertical section. Drawing) 3. Preparation for the summary 2 Summary module control module control

TYPES OF INDIVIDUAL WORK FOR STUDENTS

№ Topic Points

1. Ormokers. Composition. Characteristic. 2 Advantages and disadvantages. 2. Giomers. New generation of hybrid of 2 light-curing resin composites and glassionomer cements. 3. Silorans – improved nanocomposites. 2

9 THE STRUCTURE OF DISCIPLINE „PRECLINICAL COURSE OF THERAPEUTIC DENTISTRY”, MARKS FOR CURRENT EDUCATIONAL ACTIVITY (THE CONVERTATION OF TRADITIONAL ESTIMATIONS IN MARKS, ESTIMATION IN GRADES FOR IMPLEMENTATION OF INDIVIDUAL TASKS) module, numder of Distribution Convertation of Grades Number of Number of educational hours, of practical traditional marks into for the grades for grades for final numder of credits, classes grades implemen current module control ECTS tation of educational Traditional marks the ISRS activity of students „5” „4” „3” „2”

Module 1. Structure of Practical 6 4 3 0 6 max max teeth and preparation of classes 6,19=114 80 carious cavities  69 (in all 19) min min hours, 2,3 credits 3,19=57 40

Students which collected 57 marks are admitted to final module control. For individual work 6 marks are added Module 2. Filling Practical 6 4 3 0 6 max max materials and classes 114 80 endodontics  66 hours, (in all 19) min min 2,2 credits 57 40 Students who reseived 57 grades are admitted to final module control. For individual work 5 marks are added.

10 The convertation of estimations in rating scale into the scale of progress in studies ECTS

Estimation Statistical index Description Limits of of ECTS estimations of ECTS A The best 10% Exellent 191-200 B Next Very good 166-190 followings 25% C Next Good 136-165 followings 30% D Next Satisfactory 111-135 followings 25% E The last 10% Acceptably 101-110 Fx Repeated Unsatisfactory handing over F Obligatory Unsatisfactory, repeated course with the of studies repeated course of studies

11 Introduction

The curricula for students of dental faculties of higher medical establishments of Ukraine of the III-rd and IV-th levels of accreditation contains the course of preclinical therapeutic dentistry which tought during in the III-rd and IV- th semesters. On the basis of typical curriculum, educational qualification (EQD) and educational professional programs (EPP) of training of specialists, experimental curriculum and in accordans with principles of ECTS (European credit-transfer systems) and the order dated from 31.01.2005 № 52 approved by Ministry of Health Care of Ukraine, current educational programme has been developed by co-workers of the departments of Therapeutic dentistry. Preclinical course during the 2-nd year of studies provides thorough and profound preceding education of students, mastering of obligatory manual skills, on phantoms, which are extremely important for the future independent work in the clinic of therapeutic dentistry. Initial level of knowledges of students on the III-rd and IV-th semesters foresees knowledge of fundamental medical disciplines. The educational process is carried out according to the credit-module system in accordance with the requirements of Bolon’ process. The specific aim of study of the module 1 „Structure of teeth and preparation of carious cavities” envisages the thorough study of substantial modules „Anatomico-histological and clinico-topographical peculiarities of structure of teeth” and „Preparation of carious cavities”. Substantial module 1 „Anatomico-histological and clinico-topographical peculiarities of tooth structure ” includes: - analysis of histological structure and chemical composition of hard tissues of tooth (the dentine, the

12 cement) and the pulp, anatomico-histological and physiological structural features of separate areas of oral mucosa; - interpretation of age changes, the influence of the function of salivary glands and the quality of saliva on the condition of hard tissues of the tooth; - analysis of clinico-anatomical features of different groups of teeth; - explanation of the role of the structure and signs of teeth in the determination of their belonging to one or another group, side, upper or lower jaws. A 2 „Preparation of carious cavities” foresees: - analysis of dental instruments; - effective sterilization; - the classification of carious cavities according to Black classification; - the interpretation of the necessity to follow rules of the mode and stages of the preparation of carious cavities; - the explanation of peculiarities of preparation of carious cavities according to Black classification; - an analysis of indications to the application of different methods of preparation (classical, M.I.- therapy, ART-therapy, tunnel preparation) of carious cavities. The methodological guide contains short description of themes for each lesson, the list of control questions to evaluate every students’ knowledge of presented material, tests and situational tasks. At the end of every topic the list of recommended literature is presented, which will help students to prepare for their practical classes.

13 Practical lesson No 21

Theme: Filling materials. Classification. Main demands. Temporary filling materials. Composition, properties, and use indications.

Short description of a theme

Classification of dental filling materials Dental filling materials according to their purpose can be divided as follows: - for temporary filling, - for permanent filling, - subbase and base materials, - endodontic materials. Temporary filling materials are used for 1-2 weeks (up to one month). Artificial dentinum (zinc sulfate cement) is most common. The powder consists of zinc sulfate and zinc oxide in the ratio 3:1 and 5-10% of kaoline. The powder is mixed with water on the rough side of the glass by metal spatulas. At first the powder is given in the amount able to absorb all the water and then the powder is added by small portions to achieve an optimal consistence. The prepared mixture is taken to the cavity in on portion and condensed by cotton pellet and shaped by one of the filling instruments. Temporary filling has low mechanical steadiness to grinding. Dentin – paste is also used (it is dentinum mixed with vegetable oil). The paste becomes firm in 2-3 hours at body temperature. Zinc mixed with eugenol can be used as the temporary filling. Materials for temporary filling: timodentinum (Poland), multidentinum (red powder – for devitalized teeth, white

14 powder – during caries treatment, yellow antiseptic dentin – during endodontic procedures). Septodont (France) produces Cimpat for temporary filling: red powder (used after application of devitalizing agents) and white powder. Voco produces light curing material for temporary filling – Provicol. There are different names of dentin-pastes also, according to producent: Cimpat – Septodont (England). Demands to the permanent filling materials a. Tooth filling materials should be: - non-irritant to the pulp and gingival; - of low systemic toxicity; - cariostatic. b. Ideally there should be bonding between filling and enamel and dentine, and marginal leakage should not occur. c. Not dissolve or erode in saliva or in fluids taken into the mouth. Low water absorption is also important. d. Mechanical properties should be adequate to withstand the forces of mastication, and should be similar to those of enamel and dentine in respect of modulus of elasticity and strength. Good abrasion resistance to dentifrices and constituencies of food is also important. Restorations of posterior teeth are particularly subject to conditions of abrasive wear. e. Good aesthetic properties are required, particularly for fillings in anterior teeth. Thus the restoration should ideally match the tooth in: - colour; - translucency; - refractive index. Over a period of time there should be no staining or discoloration. f. Thermal properties:

15 - coefficient of thermal expansion should be similar to that of enamel and dentine; - low thermal diffusivity. g. Other properties: - minimal dimensional changes on setting; - ability to retain a smooth surface; - adequate working time; - radio-opacity, to enable; - detection of secondary caries; - identification of overhanging ledges; - detection of incompletely fille cavities due to trapped air.

Control questions to practical lesson

1. What are the main groups of dental materials? 2. What temporary filling materials are used in dentistry? 3. What is the purpose of using temporary filling materials in dentistry? 4. Describe the composition of the artificial dentin, used as temporary filling material. 5. What are the main demands to the permanent filling materials? 6. Innumerate the propeties which should possess an ideal dental material for permanent filling.

Situation tasks and test control

1. The powder of temporary filling material (Dentin) consists of: A. Zinc sulfate and zinc oxide B. Zinc sulfate and eugenol C. Zinc oxide and eugenol

16 D. Zinc sulfate and kaolin E. Zinc sulfate, zinc oxide and kaolin

2. The powder of Artificial dentin is mixed with water in the ratio A. 2:2 B. 2:1 C. 1:1 D. 1:2 E. 3:1

3. The time of hardening for Dentin paste as a temporary filling is: A. 8 min. B. 2-3 hours C. 1 hour D. 40 min. E. 25 min.

4. The time of hardening for Artificial dentin as a temporary filling is: A. 8 min B. 25 min C. 40 min D. 1 hour E. 2-3 hours

5. What liquid should be used for mixing of the powder of the Artificial dentin? A. Polyacrylic acid B. Orthophosphoric acid. C. Methylmethacrylate D. Eugenol. E. Distilled water

17 6. Which of the enumerated materials can be used as temporary fillings: A. Silico-phosphate, composite B. Compomers C. Zinc-eugenol cements D. Silicate cements E. All cements

7. With what instrument it is recommended to install the temporary filling into the tooth cavity A. Spatula. B. Excavator C. Tweezers D. Instruments for cavity filling E. Elevator

8. With what instrument it is recommended to remove the temporary filling from the tooth cavity A. Probe B. Excavator C. Tweezers D. Elevator E. Dental drill in a turbo handpiece

9. What are the two compounds of the Zinc which form the structure of the Artifitial dentin? A. Oxide and Sulfate B. Fluorine and Oxide C. Cloride and Nitrate D. Fluorine and Sulfate E. Fluorine and Sulfate

10. Which one of the mentioned demands to permanent filling

18 is absent in modern composites? A. Good aesthetic properties B. Translucency C. Non-irritant to the pulp D. Low systemic toxicity E. Radio-opacity

Reference literature

1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

Practical lesson No 22

Theme: Bases and liners. Composition, structure, properties, and use indications.

19 Base materials and subbase materials Subbase materials have therapeutic effect on the pulp. In the case of deep cavities even very economical tissue cutting leads to the traumatization of odontoblasts sprouts which influences the pulp of the tooth. During the preparation in deep cavities one can observe direct influence of microorganisms and products of their metabolism on the pulp, thereby existing a possibility of pH lowering in the dentinum layer near the pulp. Subbase materials have an antiseptic properties and anti-inflammatory effect on the pulp, they stimulate odontoblasts to produce mineralized dentinum (so called substantional dentine or tertiary dentine). The majority of used subbase materials include calcium hydroxide (Ca(OH)2). They have alkaline pH>12 and thus lowered pH in the cavity and normalize pulp blood circulation. Subbase materials do not possess adhesion properties to dentinum, that’s why it should be layed over in very thin amount and should not cover the whole bottom of the cavity. It is enough to put small amount (one drop of the material) with the help of dental probe on the nearest point to the pulp. Subbase materials must be covered by the base materials. There are different forms of production of subbase materials: 7. Hydrosolutions (Hypocal, Calxyl (They are prepared from the powder of Ca Hydrooxide (some have also K, Na, NaHCO3) and water. Radioopague substances (for example hydroxide of Titanium) are added to them; 8. Varnishers for cavity treatment with Ca(OH)2 (Hydroxyline, Tubulitec Alcaliner);

20 9. Oil containing substsnces with Ca(OH)2 (Gangraena Merz); 10. Cements (Dycal, Kerr-Life). These are acids connected with Ca(OH)2. One of the substances is sulicilate ether which forms the chelate complex with Ca Hydrooxide and Ca salicilate. Cement subbases can have additional substances (ethyltoluol sulfonamide) and dyes. These cements are paste- like and harden after mixing. Cement subbases cannot be used instead of base cements (they are too mild and can dissolve under the filling). One of the examples of combination of Ca(OH)2 in the base is Cp-Cap (Ca salicilate cement combined with the Zinc oxide cement).

Demands to the base materials 1. to protect the pulp from chemical, thermal and microbe influences 2. to cover all the walls of the cavity directed to the pulp 3. to be biocompatible with tooth tissues 4. to be strong in the molar teeth 5. to be of minimal solubility in oral liquid 6. in the case of using materials, raising the adhesion of composites, base ought to be acid stable and not contain eugenol. All the materials containing Ca(OH)2 cannot be used as base materials.

Base materials are divided into two main groups

varnishers/lines cements

21 Varnishers in dentistry are resins dissolved in organic solvents. After the varnish is put into the cavity the solvent evaporates and the resin remains. Liners have treatment supplements (Ca(OH)2, ZnO etc.). They are used only in shallow and small cavities. It is important that organic solvents of the liners are not compatible with the pulp (examples: Cavity-Liner, Copalite).

1. Whar is the purpose of the subbases use in dentistry? 2. What subbase materials are applied in carious cavities? 3. What are the main properties of subbase materials? 4. Enumerate the demands to base materials.

1. Pulpal SENSITIVITY is caused primarily by: A. Vibration from cavity preparation B. Thermal trauma C. Electrical trauma D. All of answers are correct E. Chemical irritation from bacteria

2. CHRONIC INFLAMMATION is caused primarily by: A. Mechanical inflammation B. Microleakage of endotoxins C. Thermal trauma D. All of the metioned factors E. Chemical irritation from dental materials

22 3. The DENTIN SMEAR LAYER increases: A. Chemical adhesion for varnishes B. Mechanical adhesion for liners C. Coverage of tubule openings D. Thermal insulation for the pulp E. Formation of reparative dentin

4. What is the THICKNESS of thermal insulation required for pulpal protection? A. 1000-2000 mm (1.000-2.000 mm) B. 10-50 mm (0.010-0.050 mm) C. 50-200 mm (0.050-0.100 mm) D. 200-1000 mm (0.200-0.500 mm) E. 2-5 mm (0.002-0.005 mm)

5. DYCAL is classified as a: A. Solution liner B. Suspension liner C. Cement liner D. Cement base E. Cement filling material

6. Dental materials that are designed as PULPAL MEDICAMENTS contain: A. Calcium hydroxide or Eugenol B. Calcium phosphate or Eugenol C. Calcium hydroxide or Methyl Salicylate D. Zinc oxide or Eugenol E. Calcium hydroxide or Zinc Oxide

7. The pH of concentrated CALCIUM HYDROXIDE solutions is: A. pH = 1-3 B. pH = 3-5 C. pH = 5-7

23 D. pH = 7-9 E. pH = 9-11

8. Which intraoral component is required to start the setting of DYCAL? A. Ca ions from tooth structure B. Higher temperatures of the intraoral tissues C. Denatured proteins in the smear layer D. Monovalent ions from saliva E. Moisture for calcium hydroxide dissociation

9. What is the key IONIC species for the setting of DYCAL and LIFE? A. Zn++ B. Ca++ C. Sn++ D. K+ E. Na+

10. Indirect pulp capping is conducted as follows: A. After the placement of on adhesive layer B. Before indirect capping procedure the pulp should be covered with isolation base C. The subbase is put on the dentin in the bottom of the cavity D. The medication is put directly on the pulp E. The subbase is put on the second visit

11. Which of the below mentioned materials belong to the group of medicinal subbases: A. Zinc phosphate cement B. All answers are wrong C. Silicate cements D. Silicophosphate cements E. Dycal

24 12. During the treatment of deep caries non-hardening subbase of Ca hydroxide was used. What is the next stage of treatment? A. Placement of the temporary filling B. Placement of the permanent composite filling C. Permanent of the glass-ionomer filling D. Etching of the caries cavity E. Etching, bonding, placement of composite filling

13. The liquid of zinc phosphate cement consists of: A. 37% ortophosphoric acid B. Acrylic acid C. Distilled water D. Aqueous solution of ortophosphoric acid (52-56% of mass) and supplements (zinc, aluminum) E. 10-50% of polyacrylicaud

1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. Seltzer and Bender’s. Dental pulp // Quintessence Publishing, 2002. 5. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

25 Practical lesson No 23

Theme: Permanent filling materials. Classification. Physical- chemical properties of cements. Indications for use.

Cements These materials are powders connected with water or aqueous solutions. Cements are divided in: - Zinc-phosphate cements; - Silicate cements; - Glassionomer cements; - Carboxilate cements; - Zinc-oxide eugenol cements. Zinc-phosphate cements are used as base materials for filling of deciduous teeth and for fixation of the crowns. They stand considerable loads, and poorly dissolve in the saliva. They provoke pulp reaction which is reversible. The pH of the cements after mixing is acid tending to be neutral in some hours. If the consistency of the cementum is more liquid, neutralization will take more time, which means more irritation to the pulp. Protection of the pulp in deep cavities is achieved by subbases. The powder of the zinc-phosphate cement consists of: zinc-oxide – 80-90% and supplementaries mostly MgO up to 10% – it makes the cement more durable. Also silicium oxide and other oxides are used. Liquid of the cement consists of the aqueous solution of ortophosphoric acid (52-56% of mass) and supplements (zinc, aluminium), the rest is water.

26 Cement is mixed on a slightly cooled glass, to decrease the amount of heat discharged during the reaction. The powder is always added to the liquid (not vice versa) by small portions to achieve the necessary consistency. After taking the powder and liquid, bottles must be closed immediately to protect the acid from moisture absorption. When the powder is opened it absorbs carbon dioxide (CO2) from the air and during mixing gasses are educed which leads to the porous structure of the cement. The reaction of hardening is exotermic. The time of hardening is 5-9 minutes. The shrinkage is 0,03-0,06% in 7 days in humid medium. Heat-conductability is the same (close to) the dentin, thus the cement doesn’t protect the pulp from thermal irritation. Silicate cements differ from zinc-phosphate mainly by the composition of the powder, which include SiO2 (up to 47%) and Al2O3 (up to 35%). These cements are rarely used because of bad adhesion and pulp irritating effect. The powder of zinc-oxide eugenol cements consist of ZnO and different Zn-compounds, the liquid is eugenol. Mostly these cements are used for temporary fillings. The cement hardens quickly in oral cavity (at body temperature). Zn-eugenol cements cannot be used with composites, because eugenol effects resins polymerization. Zn-eugenol cements have bacteriocide effect. Being derivate of phenol, eugenol can cause allergic reactions. Zn-eugenol cement cannot be used as direct pulp covering, it can provoke the exacerbation of the pulpitis. Carboxylate cements. Their composition is similar to those of Zn-eugenol cements. Liquid in 40-50% consists of polyacrylic acid. They are more viscous (sticky) than phosphoric acids and more compatible with the pulp and form chemical bonding with tooth hard tissues. But these cements

27 have greater shrinkage and are less durable (stable). The solubility of carboxylate cements is the same as that of Zn phosphate cements. These cements cannot be used in tooth areas which are exposed to great pressure.

Control questions to practical lesson 1. What groups of cements do you know? 2. What is the composition of zinc-phosphate cement? 3. What is the main difference between zinc-phosphate and silicate cements? 4. Enumerate the properties of Zn-eugenol cements. 5. What are the advantages of Carboxylate cement being compared with zinc-phosphate cements. 6. Why is fluoride release so important in a cement? 7. What is the difference in function between a cement liner and a cement base? 8. Why are polymer cements recommended for use with CAD/CAM inla\-s with poor marsrinal fits? 9. What is the minimum compressive strength required of a dental cement for adequate retention of restorations? 10. How does the solubility of phosphate cements in citric or lactic acid compare with their solubility in water? What are adhesive resin cements? 11. What agents accelerate the setting of zinc oxide— eugenol cements? 12. Why do zinc oxide-eugenol cements have a high solubility? 13. What materials can be added to zinc oxide-eugenol cements to improve their strength? 14. What effects do zinc oxide-eugenol cements have on resin restorative materials? 15. How does the composition of EBA cements differ from that of zinc oxide-eugenol cements?

28 16. WTiat factors affect the setting reaction of polycarboxylate cements? 17. Give possible reasons for the minimal effect of polycarboxylate cements on pulp. 18. What are important considerations in manipulating polycarboxylate cements? 19. Define the two types of polymer-based cement. 20. What are the principal disadvantages of polymer-based cement?

1. What properties of alumosilicate cements limitate their use in carious cavities of II-nd an IV-th classes? A. Instability to abrasion B. Chemical solubility C. Instability in colour D. Thermal expansion E. Thermal conductivity

2. The main difference between Zinc phosphate and Polycarboxilate cements is: A. Composition of the powder B. Composition of the liquid C. Indications for use D. Colour E. Thermal conductivity

3. What cement from the below mentioned can be used for filling of the deciduous tooth witout isolation with a base material? A. Silicate cement B. Polycarboxilate cement C. Silicophosphate cement

29 D. Silicate and Silicophosphate cements E. Polycarboxilate and Silicate cements

4. What are indications for use for the Zinc-phosphate cements? A. Fixation of the intracanal metal posts B. Root canals filling C. All varients are correct D. Fixation of the crowns E. As a base material

5. During the treatrment of profound caries Zinc-Oxide eugenol base has been used. Which of the innumerated materials can be fixed over this base? A. Composite resin B. Light-cured Composite resin C. Microhybrid Composites D. Cements for permanent filling E. All answers are correct

6. During the process of mixing of Zinc-phosphate cement it tends to be too hard. The operator add one drop of liquid to achieve proper consistency. Was it correct? A. The operator needs to mix a new portion of cement in proper ratio of liquid and powder B. Yes C. More liquid is needed D. It depends of achieved consistency E. It is necessary to place the mixed cement into the cavity without adding the liquid

7. Silicate cements differ from Zinc-phosphate mainly by the composition of: A. Supplements

30 B. Heat-conductability C. Liquid D. Powder E. All answers are correct

8. The main difference between Carboxylate cements and Zn- eugenol cements is: A. Composition of the powder B. Composition of the liquid C. Shrinkage D. Solubility E. Thermal conductivity

31 Theme: Glass-ionomer cement. Characteristic. Indications. Peculiarities of practical use.

Fluorine-containing aluminosilicate glasses are of particular interest. These cements contain an ion-leachable glass which can react with a water-soluble polymer acid to yield a cement. They are used not only as base materials but also as filling materials. As cement liquid can be used: 1) polycarbonic acids (polymers of alkenic acid), for example polyacrilic acids and their copolymers with itaconic and maleinic acids; 2) distilled water. Powder of Glass-ionomer cements includes of Ca-Al- silicat glass with inclusions of crystallized, saturated with Calcium-fluorine drops. Generic formula can be as follows: SiO2-ZnO2-TiO2-Al2O3-AlF3-LaF3-CaF2-NaF-AlPO4- Ca3PO4. After filling with glass-ionomer it releases fluorine for a long period of time (it ensures carious-static effect in the border line between the walls of the cavity and the filling materials). It is important to protect glass-ionomer filling from dehydratation and humidity (it is achieved by varnishers after filling). Glass-ionomer cements can not be well polished (because of the connection of mild polycarboxylic gel and hard silicat glass). Optimal surface of the filling is achieved with the use of matrixes. After the end of hardening (24 hours)

32 processing is made with fine grinded diamond burnishers and disks covered with aluminium oxides. What is very important about glass-ionomer cements – is their ability to form chemical bonding with tooth hard tissues. There exist ionic and covalent connections among carboxylic groups of polyacrylic acid and inorganic components of enamel and dentine. Resin-enamel connection is 6 times stronger than the connection of glass-ionomer cement – enamel. To take the connection better dentin surface can be conditioned with 25% polyacrylic acid. Not having enough mechanical stableness and aesthetics, glass-ionomer cements can not be used in class II and IV cavities.

Classification and applications Three types of cement, glass-ionomer should be distinguished: a. Type I, luting cements. These are fine grain materials with low film thickness when set (Aquacem (Dentsply), Fuj Fuj Ortho (GC), Sen-Fix (Sendentel), Aqua Meron, lonofix (Voco), Ketac Cem (ESPE). b. Type II, restorative materials (Chemfil Superior (Dentsply), Fuji (GC), Ketac Molar (ESPE), Ionofil Molar (Voco), Sen-Fill, Sen-Fill Ague (Sendental), Ionofil, Aqua Ionofil (Voco). Examples of applications include: - abrasion and erosion cavities; - restoration of deciduous teeth; - restoration of Class III and V carious lesions; - repairing defective margins in restorations. c. Type III, lining materials (Gem Base (DCL), Base- Line (Dentsply), Lining Cement (GC), Sen-Line (Sedental), Shofu-Base Cement, Shofu Liner Cement (Shofu), Viva-Glass Liner (Vivadent), lonobond, Aqua lonobond (Voco), Ketac Bond (ESPE) and fissure sealants, for: - sealing occlusal fissures;

33 - cavity lining, particularly if cariostatic action is required; - as a lining under composite filling materials; one such technique involves etching the cement as well as the tooth enamel, so that micromechanical bonding between composite and cement is achieved. Because of their nature, glass polyalkenoate cements are contraindicated for: - amalgam replacements; - class IV restorations; - replacement of lost cups areas.

Manipulation a. Mix the cement at the correct ratio – this is of critical importance for Type II cements. b. Rapid mixing is required, ideally by mechanical mixing, or by the use of a refrigerated glass slab. c. Moisture isolation of the tooth is desirable. d. A surface conditioner should be applied to dentine. e. Pulpal protection by a calcium hydroxide cement is important if the dentin over the pulp chamber is less than 0,5 mm thick. f. Protection of the freshly set cement from moisture by application of, for example, a varnish is important. g. After polishing, varnish should be re-applied.

Light activated cements Recently, materials have become available, the setting of which is activated by the application of visible light, using the same light system as designed for composite resins. Essentially, two setting reactions occur: - further polymerization of the poly(alkenoic acid) which, in these products, contains polymerisable double bonds;

34 - the conventional acid-base reaction.

Control questions to practical lesson 1. What is the source of fluoride in a glass-ionomer cement? 2. What are resin-modified glass ionomers? 3. What are the advantages of light curing glass-ionomer cements? 4. What are the major advantages of glass-ionomer cements?

1. What is the POWDER component in GICs (traditional glass ionomers)? A. Zinc oxide B. Silica C. Lithium aluminosilicate D. Aluminosilicate glass E. Alumina

2. What is the LIQUID component in GICs (traditional glass ionomers)? A. Polyacrylic acid B. Polymethacrylic acid C. Polymethyl methacrylate D. BIS-GMA polymer E. Phosphoric acid 3. Which one of the following has NOT been used as part of the GIC liquid composition? A. Acrylic acid B. Tartaric acid C. Maleic acid D. Citric acid

35 E. Itaconic acid

4. How is F ion released from a cured GIC? A. Intraoral fluids dissolve it out of the glass particles B. CaF2 salts dissolve and release the fluoride C. Fluoride ions in the matrix are released D. Sodium fluoride salts release the fluoride E. Acid in the oral environment dissolves the residual glass

5. What causes the initial setting reaction in a GIC? A. Release of fluoride ions from the aluminosilicate glass B. Crosslinking of polyacrylic acid polymer chains by aluminum ions C. Loss of water from the matrix phase D. Crystallization of the dissolved salts from the powder particles E. Crosslinking of polyacrylic acid polymer chains by calcium ions

6. What causes the final setting reaction of in a GIC? A. Release of fluoride ions from the aluminosilicate glass B. Crosslinking of polyacrylic acid polymer chains by calcium ions C. Crosslinking of polyacrylic acid polymer chains by aluminum ions D. Loss of water from the matrix phase E. Crystallization of the dissolved salts from the powder particles 7. What produces chemical adhesion to tooth structure for a GIC? A. Chelation of polyacrylic acid with calcium ions B. Chelation of polyacrylic acid with aluminum ions C. Reactions of the fluoride ions with hydroxyapatite D. Precipitation of calcium phosphate from the dissolved powder 36 E. Precipitation of calcium oxide

8. Contaminated or overly wet tooth surfaces interfere with the: A. Adaptation of the cement for chemical bonding B. Initial setting reaction C. Final setting reaction D. Release of fluoride ion E. Color of the final cement

9. Which one of the following is key during the first 24 hours for conventional GIs? A. Protection against contact with moisture B. Protection against intraoral acid contact C. Protection from ultraviolet radiation D. Protection against salivary protein contact E. Protection against fluoride release

10. What is the time of maximum fluoride release RATE out of the cement? A. During the first few minutes B. During the first 24 hours C. During the first month D. During the first year E. After the first year

11. Which one of the following is NOT a major use for glass ionomers? A. Class V filling material B. Liner C. Base D. Cement E. Tunnel preparations

37 12. Which application takes best advantage of chemical adhesion of glass ionomers? A. Class V filling material B. Liner C. Base D. Cement E. Tunnel preparations

13. Which application takes best advantage of the fluoride release of glass ionomers? A. Liner B. Base C. Root caries restorations D. Retrograde filling material E. Core

14. Which one of the following has the most influence on the final mechanical and chemical properties of conventional GI cements? A. Fluoride content of the aluminosilicate glass B. Mixing technique C. Powder-to-liquid ratio D. Acidity of the mixture E. Reaction exotherm 15. What is the mechanism of reinforcement of metal-modified GIs? A. Addition of stronger powder particles B. Addition of particles which can be chelated by matrix C. Addition of particles which can dissolve and affect reaction D. Addition of particle that accelerate fluoride release E. Addition of insoluble particles

38 16. What is the major difference between chemically-cured and light-cured (LC) GIs? A. LC produces second matrix B. LC version has no acid-base reaction C. LC versions accelerate release of F from aluminosilicate glass D. LC eliminates all moisture sensitivity of material E. LC version increases adhesion to tooth structure

17. Which one of the following is not part of a "multiple- curing" GI system? A. Ca++ ion crosslinking of acid-functional polymer chains B. Al+++ ion replacement of Ca++ crosslinking C. Visible light polymerization of matrix monomers into polymer D. Chemical curing of matrix monomers into polymer E. F ion crosslinking of polymer chains

18. Which one of the following materials is a traditional glass ionomer cement? A. Vitremer cement B. Fuji II C. Advance D. Dyract E. Ketac-Cem 19. What is the term used for glass ionomers that are very similar to composites? A. Hybrid ionomers B. Compomers C. Hybrid composites D. Giomers E. Glass ionomer modified composites

39 20. ART is the acronym for which of the following? A. Advanced Resistance Technique B. Atraumatic Restorative Technique C. Advanced Restoration Therapy D. Assisted Re-Enameling Technology E. Archive of Restoration Technologies

21. What is the primary goal of ART? A. Prevention and treatment of dental caries with minimal instrumentation B. Delivery of F from restorations for patients at high risk to dental caries C. Relief of patient pain D. Alternative to dental amalgam restorations E. Inexpensive dentistry

22. Which of the following re-charging sources is the most effective? A. Topical fluoride treatments B. Daily fluoride mouth rinses C. Fluoride-containing toothpastes D. Ice tea E. Fluoride supplements

23. How long does re-charging of glass ionomer materials effect F-release? A. 1-2 minutes B. 1 -2 days C. 1 -2 weeks D. 1-2 months E. 1 -2 years

Reference literature 40 1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

Theme: Amalgam. Physical-chemical properties. Methods of preparation and filling with amalgams.

Definition: an amalgam is an alloy of mercury with another metal or metals. Mercury is a liquid at room tempetature; its freezing point is – 39oC. It can readily undergo amalgamation reactions with metals such as silver, tin and copper to give a set material. Alloys for the preparation of dental amalgam may be broadly classified into two types: - сonventional alloys, containing less than 6% copper – the chemical formulation of these materials has

41 been very little changed over the years (Quicalloy, Standalloy, Stabil B); - сopper enriched alloys, which have become available since the 1970s (sometimes referred to as „Higher copper”alloys). Conventional alloys contain the following principal constituents: - Silver – 67-74%4 - Copper – 0-6%; - Tin – 25-27%; - Zinc – 0-2%. Copper enriched alloys are of the following types : a. Blended alloys, sometimes referred to as „dispersion modified” alloys; these contain two parts by weight of conventional composition lathe cut particles plus one part by weight of spheres of a slver-copper alloy (70% Ag + 30% Cu, approximately). Representatives: Dispersalloy, Luxalloy, Amalcap plus. The overall composition is approximately: - Silver – 69%, - Copper – 13%, - Tin – 17%, - Zinc – 1%. b. Single composition alloys: a number of different types are available, including: Ternary alloys in spherical form, either: - Silver 60%, Tin 25%, Copper 15% (Representatives: Oralloy, Dispersalloy) or - Silver 40%, Tin 30%, Copper 30% (Representatives: Duralloy, Vivalloy, Sybralloy, Valiant). An alloya similar to the first of those detailed above, but containing particles in spheroidal form – that is, that particles are not perfectly spherical. Quaternary alloys in spheroidal form, containing:

42 - Silver 59%, Copper 13%, Tin 24%, Indium 4%. c. Alloys which are the reverse of type (a) above are available in some countries. That is, they contain 2 parts by weight of spheres of 60% Ag, 25% Sn and 15% Cu, plus 1 parts by weight of conventional alloy. This latter component may be either as spherical or fine grain lathe cut particles.

1. Are dental amalgams a health hazard? 2. Why is dental amalgam so popular, even though it is not esthetic? 3. What are the advantages and disadvantages of using a bonding agent with amalgam restorations? 4. How does copper affect the set microstructure of amalgam? 5. How can the working time of amalgam be controlled? 6. Should a zinc-free amalgam be used? 7. Can some amalgams be finished the same day they are placed? 8. Why are spherical amalgams difficult to condense? 9. Does creep predict marginal fracture? 10. Why are seal/bond amalgam restorations of particular interest? 11. How safe are amalgams?

1. Dental amalgam is DEFINED as: A. A mixture of mercury with any metal B. A mixture of mercury with silver C. A mixture of mercury with silver and tin D. A mixture of mercury with any zinc alloy E. The alloy for mixing with mercury 43 2. How much MERCURY (by weight) is in a modern set dental amalgam? A. >60% B. 55-60% C. 50-55% D. 45-50% E. 40-45% 3. What is the COPPER CONTENT in LOW COPPER dental amalgam alloys? A. 0 - 5% B. 5 -12% C. 12-30% D. 30-38% E. 38-50%

4. What COMPONENTS are typical in LOW COPPER dental amalgam alloy? A. Ag-Sn B. Ag-Sn-(Cu)-(Zn) C. Sn-Cu-Zn D. Ag-Sn-Cu-(Zn) E. Ag-Sn-Cu-Zn

5. What COMPONENTS are typical of HIGH COPPER dental amalgam alloy? A. Ag-Sn-Cu B. Ag-Sn-Cu-(Zn) C. Ag-Sn-Zn D. Ag-Sn E. Sn-Cu-Zn

6. Which one of the following terms is NOT synonymous with the rest in the list? A. Comminuted particles B. Filings

44 C. Lathe-cut particles D. Irregular particles E. Spherical particles

7. COMMINUTION is: A. Milling or filing an ingot into powder particles B. Heat treatment to control the setting reaction of powder particles C. Decreasing the mercury content of an amalgam D. Eliminating the copper content of an amalgam alloy E. Elimination of the tarnish on an amalgam restoration

8. Which one of the following is NOT a standard method of classification for dental amalgams? A. Particle Shape B. Copper Content C. Mercury Content D. Number of Powder Particles E. Zinc Content

9. NEW TRUE DENTALLOY dental amalgam alloy is made as what type of powder? A. Irregular B. Irregular + Irregular C. Irregular + Spherical D. Spherical + Spherical E. Spherical 10. What is the reason Zn is used in a dental amalgam alloy? A. Oxygen scavenger in production B. Reducing mercury vapor release from the set restoration C. Improved hardness D. Controlling the setting reaction E. Prevent tarnishing

45 11. What is the reason Sn is included in a dental amalgam alloy? A. Corrosion protection B. Improved ductility C. Prevent tarnishing D. Particle dissolution during reaction E. Increased tensile strength 12. What is the reason Cu is included in a dental amalgam alloy? A. Corrosion protection B. Increased ductility C. Prevention of tarnishing D. Reduction in amalgamation speed E. Improved condensability 13. The SETTING REACTION of dental amalgam proceeds primarily by: A. Dissolution of the entire alloy particle into mercury B. Dissolution of the Cu from the particles into mercury C. Mercury reaction with Ag on or in the alloy particle D. Formation of Zn-Hg crystals E. Precipitation of Sn-Hg crystals

14. What is the ABBREVIATION for the Sn-Hg phase? A. Gamma (= Y) B. Gamma-1 (= YI) C. Gamma-2 (= Y2) D. Beta (= p) E. Epsilon (= s)

15. Which phase in a set dental amalgam contains most of the MERCURY? A. Gamma (= Y) B. Gamma-1 (= YI) C. Gamma-2 (= Y2) D. Eta (= n)

46 E. Epsilon (= s)

16. Which one of the following variables does NOT influence the amount of DIMENSIONAL CHANGE during setting of dental amalgams? A. Alloy particle size or shape B. Hg/alloy ratio C. Trituration time D. Condensation method E. Burnishing technique

17. What does the batch (or lot) number code of "040501" on an amalgam alloy mean? A. It was produced on January 5, 2004 B. It was shipped on January 5, 2004 C. It is no longer acceptable after January 5, 2004 D. That it contains 4Sn-5Cu-1Zn in the alloy E. That it should not be used before January 5, 2004

18. A PROPERLY TRITURATED dental amalgam mixture should look like a: A. Grainy, dull mass B. Coherent, smooth mass C. Grainy, wet mixture D. Fibrous, dull mass E. Fibrous, shiny mass

19. Which one of the following produces the MOST mercury- rich matrix removal? A. Condensation late in the working time B. Use of the largest condenser tip C. Use of the most load during condensation D. Non-overlapping condensing strokes E. Burnishing

47 20. What is the effectiveness for HIGH COPPER dental amalgams? A. 1-2 years B. 4-5 years C. 8-12 years D. 20-25 years E. 30-50 years

21. Which one of the following mechanisms of FAILURE is most common for LOW COPPER dental amalgam? A. Excessive tarnish B. Bulk fracture C. Intergranular corrosion of the occlusal surface D. Dental caries E. Marginal fracture

22. Which one of the following mechanisms of FAILURE is most common for HIGH COPPER dental amalgam? A. Excessive tarnish B. Bulk fracture C. Intergranular corrosion of the occlusal surface D. Enamel wall fracture from thermal expansion stresses E. Marginal fracture 23. MARGINAL FRACTURE of dental amalgam is NOT associated with this property. A. Compressive strength B. Creep C. Mercury content D. Electrochemical properties E. Thermal conductivity

24. Which one of the following does NOT affect the strength of dental amalgam? A. Time between trituration and condensation B. Mercury content

48 C. Zinc content D. Condensation effectiveness E. Porosity

Theme: Composites resins. Classification. Composition. Characteristic. Indications for use. Filling materials of the main manufactures.

Composites resins were introduced by Bowen (1962) for the first time. Bowen developed a BIS-GMA composite resin. A high percentage of an inter filler was dispersed in the

49 resin to produce higher strength and lower coefficients of thermal expansion. Contemporary composite resins consist of three main components: 1. Organic matrix. 2. Dispers phase (Filler). 3. Connecting phase (copolymers).

1. Organic matrix. Composite matrix in soft state consists of monomers, initiators, stabilizators, dyes and pigments and other supplements. As monomers polyfunctional metacrylates with simplified formula MA-R-MA are used. MA – are the residual complex ethers of metacrylic acid. R – intermediate link which can be formed by aliphatic lines, uretanprepolymers, aromatic rings and polyethers. Molecules of resin’s matrix have minimal toxic effects, are colour stable, have good physical characteristics. Initiators – are matrix components, which by chemical or physical activators dissociate to active radicals which react with double links of monomers. These reactions result in the production of polymer lines. The activity of initiators is the decisive factor in the material’s hardening. (The degree of polymerization). The higher is the polymerization degree, the higher will be mechanical and physical characteristics of matrix. Initiators also influence composite colour. Stabilizators (inhibitors) – sterine phenols prevent premature polymerization. 2. Connecting phase (colorymer). Connection of the filler and the matrix depends on the silanization of the filler. As silanization agent 3 metacrylol- oxipropyl-trimetoxisilan is used. During the polymerization not

50 all double links of resins are involved. Residual double links form 45%. This indicates the presence of residuum monomer. In matrix there are also some other products which partially do not react. They may be toxic for pulp. Shrinkage after polymerization of the used composites is 1,7-6% in mass. It can lead to the existence of tensions inside the resin and appearing of cracks on the surface of filling. 3. Dispers phase. To make resin matrix more stable mechanically and physically inorganic fillers are added. They are quarts, ceramics, silicon dioxide (SiO2). Classification of composite resins is based on the type and size of fillers being used. Macrofillers (quartz, glass, ceramics) the mean size of particles is 1-100 mcm the meddle size of particles 1,5-5 mcm. The size of particles is larger than the length of light waves (they are seen by the eye). Fillers particle fall out of matrix because of different hardness. After polishing the surface becomes rough. These materials do not need polishing. They have low stability to grinding („Concise”, „Valux” (3M), „Estilux”). Composite resins with microfillers. Size of particles is less than 1 mcm. They contain highdispersible silicic acid (silicon oxide) with particles 0,007 mcm to 0,04 mcm. All particles are spherical. The general quantity of filler can be 70-80% on the average 50%. These materials are polished well and have surface luster. Diameter of particles is less than the length of light waves. These composites are more stable to grinding. But polymerization shrinrage is large, hardness (in Vikers units) and elasticity is less than in order composites. They are not appropriate for filling cavities class I, II, IV. („Silux Plus” (3M), „Helioprogress”, „Heliomolar” (Vivadent)).

51 To unit positive properties of abovementioned two groups of composite resins hydrid composite resins were introduced. These resins have at an average 85-90% (by mass) macroparticles and 10-15% microparticles. General contents of filler particles is 85%. Finegrinded hydride composite resins contain macrofillers with diameter less than 2 mcm. They are good in polishing. These composite resins are used in filling the cavities of all classes (I, II, III, IV, V). Hydrid composites can be devided into composites with particles 0,04-4 mcm – (Brilliant (Coltene), Herculite XR (Kerr), Degufill H (Degussa) with high esthetic properties which are recommended for front teeth reconstruction and composites (P-10, P-50 (3M), Polofil Molar (Voco) with particles 0,04-50 mcm with 87,5% of filler. They are strong but less esthetic. For filling cavities class I and II. Modern hydrid composits can be called microhybrid and are used in filling a;; classes of cavities. Average size of particles in this composites are 0,7-0,9 mcm. Herulite RV, Prodygy (Kerr) Tetric (Vivadent) Brilliant Esthetic Line (Coltene) Polofil Supra (Voco) Solitaire (Kulzer0 Charisma (Kulzer) Flow line composites: Revolution (Kerr) Durafill (Flow) Flow line composites are poorly filled what allows to put them without condensation (the average size of particles is less than 1 mcm) with filler less than 60%.

52 1. Describe the composition ofcomposite resins. 2. How are composite resins classified according to the size of inorganic filler? 3. Enumerate the representatives of microhybrid composite resins. 4. What is the general composition of resin composite restorative materials? 5. How have composites overcome many of the problems of unfilled resin restorative materials? 6. How well are composite materials competing against dental amalgam? 7. Although microfilled composite materials have inferior mechanical properties, they continue to be widely used. Why? 8. What is the general composition of resin composite restorative materials? 9. What are the applications for resin composite restorative materials? 10. How long do composite restorations last? 11. What are the advantages of fine-particle composites? 12. What are the advantages of microfilled composites? 13. What is a hybrid, or blend, composite? 14. What is polymerization shrinkage, and why is it a problem? 15. Which restorative materials release fluoride? List them in order of amount released. 16. What is the material of choice for cervical restorations?

1. Which ONE of the following is NOT a reason for utilizing composite technology in dentistry? A. Metal, ceramic, or polymer alone does not have the correct properties to replace tooth structure B. In situ molding requires a fluid phase for flow

53 C. In situ adhesion requires a fluid phase for physical and/or chemical bonding D. In situ setting avoids built in mechanical stresses 2. The major shortcoming of the rule-of-mixtures is that it accounts for only ONE of the following factors, which is: A. Arrangement factors B. Bonding factors C. Composition factors D. Defect factors 3. Which ONE of the following is NOT a stage in chain reaction polymerization? A. Activation B. Initiation C. Configuration D. Propagation E. Termination 4. Which ONE of the following species is comparatively high concentration in the average composite composition? A. Colorants B. Initiator C. Accelerator D. UV stabilizer E. Low MW monomer 5. Which of the following is FALSE about chain reaction polymerization reactions during the setting of composite materials? A. Fast B. Involves double bonds C. Endothermic D. Requires initiation E. Involves acrylic monomers 6. The BIS-GMA monomer unit is: A. Mono-functional B. Di-functional C. Tri-functional 54 D. Tetra-functional E. Penta-functional

7. The reactive end groups of BIS-GMA monomer are most similar to which ONE of the following structures? A. Bisphenol-A B. Methyl methacrylate C. Benzoyl peroxide D. Methyl acrylate E. Urethane 8. All of the following are true about BIS-GMA monomer, EXCEPT: A. Includes a Bisphenol-A nucleus in the backbone B. Is high viscosity C. Is highly volatile D. Is called Bowen's resin E. Is impossible to purify by crystallization

9. Which of the following is not present in an auto-polymerizing dental composite? A. BIS-GMA B. BPO C. DHPT D. Silane E. PMMA 10. For silane coupling agents to effectively bond filler particles to matrices, which chemical species must be present on the filler particle surfaces? A. Si-O B. Zn-O C. Ba-O D. Zr-O E. H2O

11. Which of the following does not impact the viscosity of a unset composite? A. Volume fraction of filler

55 B. Viscosity of the resin C. Surface area-to-volume ratio of the filler D. Benzoyl peroxide concentration 12. Which ONE of the following potential fillers can NOT be silanated? A. Quartz B. Aluminosilicate glass C. Lithium aluminosilicate glass D. Silica E. Barium sulfate 13. Which one of the following is NOT a category of dental composites? A. Packables B. Flowables C. Nanocomposites D. Microfills E. A R T

14. What types of fillers are mixed together in standard hybrid composites? A. Midifiller and Minifiller B. Minifiller and Microfiller C. Microfiller and Nanofiller D. Midifiller and Microfiller E. Minifiller and Nanofiller

15. What types of fillers are mixed together in mini-hybrid composites? A. Midifiller and Minifiller B. Minifiller and Microfiller C. Microfiller and Nanofiller D. Midifiller and Microfiller E. Minifiller and Nanofiller

56 16. What types of fillers are mixed together in nano-hybrid composites? A. Microfiller and Nanofiller B. Minifiller and Nanofiller C. Microfiller and Nano-clusters D. Microfiller and Nanomers E. Nanomers, Nanoclusters, and Midifiller

17. Which one of the following is not a true statement about biofilms? A. The base layer involves cells attached by a polysaccharide coating. B. Biofilms have extensive channels among mushroom plumes of cells. C. Biofilms can migrate across a surface to relocate the entire film. D. Cells in biofilms easy destroyed by standard antibiotics. E. Biofilms are found universally in moist environments regardless of bacterial cell type.

18. Which one of the following statements characterizes second generation flowable composites? A. Much better flow than first generation products. B. All products are almost the same strength as standard hybrid composites. C. Much greater depth of cure than regular composites. D. Do not adapt well to bonded dentin surfaces. E. Are more difficult to cure with visible light than other composites.

19. What is the reason for applying several coats of primers, self-etching primers, or self-etching adhesives during bonding procedures? A. Insure adequate film formation after solvent loss B. Increase the strength of the bonding layer

57 C. Increase the water resistance of the cured film D. Increase the fatigue resistance of the adhesive E. To minimize oxygen inhibition during VL curing 20. What is the typical solvent level range for dentin bonding systems? A. 10-30% B. 20-50% C. 45-50% D. 55-60% E. 60-90%

21. What is the hybrid layer? A. Zone of collagen surrounded by resin within intertubular dentin B. A layer of resin in which there is a combination of filler particle sizes C. A double layer produced by primer and then bonding agent D. Resin that has mixed with dentinal fluid and filled the tubules E. Any resin layer that includes HEMA in the composition

22. What is the third major category of variables affecting visible light curing in addition to "curing equipment factors" and "procedural factors"? A. Restoration factors B. Patient factors C. Intraoral location factors D. Oral hygiene factors E. Surface contamination factors

23. What is the active absorber of visible light in a dental composite that initiates polymerization? A. BIS-GMA B. Glass filler C. Silane coupling agent D. Camphoroquinone

58 E. Hydroquinone

24. What is the minimum output expected for standard QTH visible light curing units? A. 100 mW/cm2 B. 200 mW/cm2 C. 300 mW/cm2 D. 400 mW/cm2 E. 600 mW/cm2

25. What is the standard operating output for many QTH visible light curing units? A. 100 mW/cm2 B. 300 mW/cm2 C. 600 mW/cm2 D. 1000 mW/cm2 E. 1500 mW/cm2

26. What is the standard output for third-generation LED visible light curing units? A. 100 mW/cm2 B. 200 mW/cm2 C. 300 mW/cm2 D. 600 mW/cm2 E. 800-1000 mW/cm2 27. What happens to the visible light generated by QTH units that is not the correct wavelength to be absorbed by CQ? A. Passes completely through restorative material B. Scattered by the glass filler particles into adjacent tooth structure C. Absorbed and converted into heat D. Reflected by the surface of the restoration as light E. Absorbed and re-emitted as infrared light

59 28. What is the largest volume of glass ionomer sold in the world today? A. Giomer B. Compomer C. Resin-modified glass ionomer D. Conventional glass ionomer E. Resin-reinforced glass ionomer for ART technique

Theme: Adhesive systems for enamel and dentin.

60 Enamel conditioning (enamel etching) . Composite resins do not form chemical connection with teeth hard tissues. Polimerizational shrinkage takes place after the hardening of the material what leads to the decrease of filling’s volume. As a result fissure between the filing and tooth wall appears. And this is a precondition (prerequisite) for retaining of microorganism, discoloration of filling’s margins and secondary caries origin. To achieve better filling-enamel connection, before insertion of filling enamel surface has to be conditioned (for the first time recommended in 1955). Stages of enamel conditioning: - сleaning of the enamel by prophylactic paste in order to remove organic remnants; - enamel beveling; - protection of the operative field from the saliva; - etching procedure by 37% phosphoric acid (30 sec); - washing out of the acid and drying the surface (it looks white without the lustre). Dentin conditioning . Chemical and structural composition of dentine (dentinal tubules with fluid organic components and smear layer) excludes micromechanical adhesion with hydrophobic composites. Special agents have been elaborated to connect dentin and composite resins. Chemical link is achieved (due to this agents) with organic and inorganic dentine components. Before agents (primer) is put to dentinal surface the latter is etched with acids. It may be citric (10%), phosphoric (10-40%), polyacrilic acids. Primers usually includes hydrophilic monomers soluble in water and other solvents (acetone, alcohol). Supplementary primer solutions can include maleinic acid and glutaraldehyd. They from intermediate layer between wet dentin surface or smear layer and composite. 3 Different types of composite-dentin links are know:

61 I. Smear layer is only modifiered by the primer and not removed. Representative: „Pertac universal Bond” (ESPE), „ALL-Bond-2” (Bisco). II. Smear layer is partially removed. Maleinic acid is used in concentration 2,5-4% of mass. After the partial dissolution of smear layer hydrophilic monomers of primer penetrates dentinal canals, forming retentional connections. As a result hydrid layer is formed were molecules of primer are bound up with precipitated smear layer. Representation: „XR-Bond” (Kerr). III. Smear layer is completely removed and simultaneously demineralization of intertubular and peritubular dentin is taking place. Ortophosphoric acid (20% or 37%) is used in dentine etching in this case. Representatives: „All-Bond”, „All-Etch” (Bisco) Dentadhesive (Kultzer), Scotchbond-2 (3M), Syntac (Vivadent). There are several generations of dentin adhesive system, the I generation of adhesives bonds dentine and acrylic materials (Cosmic Bond (De Tray). Adhesive forces were 1-3 Mpa. II generation of adhesives – provided connection of dentinal Ca with chlor-phosphate groups and increased adhesive forces 3 times as much as those of the I generation. In the III generation of adhesives alumosilicates, 4 META, HEMA etc. are used as active groups (Amalgobond (Parkel USA), Clearfilphoto Bond (Kuraray), Gluma (Bayer), Scotchbond-2 (3M). Adhesive forces (were 12-18 Mpa). Adhesives of the forth generation are widely used in modern techniques. They produce a wide hydrid zone, penetrating deep into dentinal tubules. They include PENTA, which has hydrophobic and hydrophilic molecules. It allows active connection with Ca ions of enamel and dentin as well as with collagen – organic part of dentin.

62 This dual chemical connection in addition to micromechanical connection produces connection with dentin adhesive forces being of 25-27 Mpa. Adhesive of the IV generation except PENTA include other dymethacrelates TEDMA, UDMA, HEMA. To increase absorption of primers into dentinal tubules acetone, etanol and other dissolvents have been added to them. Adhesive of the forth generation are more elastic and include fluor to decrease tooth sensibility. Representative: „Dentadhesive” (Kultzer), „Pro Bond” (Dentsply), „Scotchbond MP Plus” (3M), „Syntac” (Vivadent), „Optibond” (Kerr), „Art Bond” (Coltene Whaledent). The fifth generation of adhesives are composed to simplify the 3-stage procedure of bonding (etching, primer and bond application). They unite the properties of primer and bond in one solution. Representatives: „One-Step” (Bisco), „Prime & Bond 2,0”, „Prime & Bond 2,1” (Dentsply), „Single Bond” (3M), „Optibond Solo” (Kerr), „Gluma bond” (Kultzer). The adhesive forces in the adhesives of the V generation are 27-31 MPa. It is important when using this systems not to overdried dentinal surface, which leads to the collapsing of collagen fibers and deterioration of the adhesive’s penetration deep into dentinal tubules. One of the newest representative of the V generation adhesives is the system Promt L Pop (ESPE). Its three ingredients are connected just before usage and obtained substance is easily applied to the prepared tooth surface by special applicator.

63 1. What is the aim of enamel etching? 2. Enumerate the stages of enamel conditioning. 3. Why is the connection of dentin and composite resins difficult? 4. What types of composite-dentin connection are known? 5. Describe the advantages of dental adhesives of the 4-th and 5-th generations. 6. Named the representatives of dental adhesives of the 4-th and 5-th generations. 7. Why is wetting by an adhesive so important for bonding to tooth structure or any other material: 8. Why is the strength of enamel and dentin a limiting factor in the adhesive bond strength? 9. What is the essential role that hydrophilic primer coupling agents play in the formation of the hybrid layer? 10. How could the geometry of a restoration affect the final bond strength to tooth structure? 11. Miy does surface tension exist in liquids? 12. How does wetting affect capillary' penetration of a liquid? 13. How do absorption and adsorption differ? 14. Name three colloidal systems of importance to dental materials. 15. Which properties affect the penetration rate of liquids into capillaries? 16. In terms of innovation, would the bonding of restorative materials to dentin by etching and forming a hybrid layer be classified as a major, medium, or minor product improvement?

64 1. The principal goal(s) of bonding are: A. Sealing and retention B. Esthetics and reduction of postoperative sensitivity C. Retention and reduction of tooth flexure D. Strengthening teeth and esthetics E. Sealing and thermal insulation

2. Which one of the following applications does NOT involve an adhesive joint? A. Enamel bonding system B. Pit-and-fissure sealant C. Dentin bonding system D. Amalgam bonding system E. Composite cement

3. Which one of the following applications does NOT involve an adhesive joint? A. Dentin bonding system B. Composite resin cement C. Surface sealant D. Amalgam bonding system E. Orthodontic bonding system

4. Which ONE of the following is NOT a major requirement for development of good adhesion? A. Clean adherend B. Calcium ions present for bonding C. Good wetting D. Intimate adaptation E. Good curing

5. Dentin bonding systems involve which of the following exclusive joint components? A. Adhesive only B. Adherend only 65 C. Adhesive/adherend D. Adhesive/adherend/adhesive E. Adherend/adhesive/adherend

6. What is the typical shear bond strength range for enamel bonding systems? A. 2-6 MPa B. 6-12 MPa C. 12-18 MPa D. 10-22 MPa E. 22-35 MPa

7. What is the typical shear bond strength range for newer dentin bonding systems? A. 2-6 MPa B. 6-12 MPa C. 12-18 MPa D. 18-22 MPa E. 22-35 MPa

8. Which category of factors is most important in determining clinical performance? A. Operator factors B. Tooth factors C. Location factors D. Materials factors E. Patient factors

9. Which of the following correctly describes the shape of hydroxyapatite crystals? A. Cylindrical B. Parallelopipeds C. Dodecahedrons D. Hexagonal rods E. Keyhole shaped tubes 66 10. At which location in enamel is the density of enamel crystals the lowest? A. Prismless enamel B. DEJ C. Center of enamel prisms D. Edges of enamel prisms E. Facial enamel

11. Which of the following is not a conditioner? A. Phosphoric acid B. EDTA C. Maleic acid D. Citric acid E. BIS-GMA

12. What is the principal mechanism for enamel bonding? A. Physical bonding B. Primary chemical bonding C. Hydrogen bonding D. Micro-mechanical bonding E. Incoherent bonding

13. In normal dentin, how far does an odontoblastic process extend from the cell? A. 10-20 |im B. 0.5 mm C. Most of the way to the DEJ D. Half way to the DEJ E. 1 mm

14. What is the typical volume of dentin occupied by dentinal tubules in the outer third of dentin? A. 50% 67 B. 40% C. 25% D. 14% E. 5%

15. What is the principal mechanical for dentin bonding? A. Physical bonding B. Primary chemical bonding C. Hydrogen bonding D. Micro-mechanical bonding E. Chelation bonding

16. Which one of the following is most important event for dentin bonding? A. Smear layer removal B. Smear plug removal C. Peritubular dentin decalcification D. Intertubular dentin decalcification E. Collagen denaturation

17. What is the hybrid zone? A. Decalcified peritubular dentin B. Embedded smear layer C. Embedded smear plugs D. Bonding agent/ composite interface E. Embedded smear layer and intertubular dentin 18. Which of the following products was the first to represent a 1-component DBS? A. Prompt L-Pop B. SingleBond C. Optibond Solo D. One-step E. Clearfil Liner Bond

68 19. When a ceramic inlay is bonded, which of the following interfaces does NOT involve chemical bonding as part of the joint? A. Enamel/Bonding Agent B. Bonding Agent/Composite Cement C. Composite Cement/Coupling agent D. Coupling Agent/Ceramic

20. When a ceramic inlay is bonded, which of the following do NOT involve micromechanical bonding in the joint? A. Enamel/Bonding Agent B. Dentin/Bonding Agent C. Bonding Agent/Composite Cement D. Composite Cement/Ceramic

69 Theme: Self-curing composite resins. Properties, indications for use, peculiarities of treatment.

Self-curing composites are the composites in which reaction of polymerization is initiated by chemical substance – benzoil peroxide-amine. All of the composites of the type consist of two parts: paste-paste, paste-liquid, powder-liquid. These composites as compared to modern light-curing composite resins are characterized by: - quick wearing, which depends on the inner porosity and degree of polymerization; - tendensy to colour change (grayish, yellowish shade), which depends on the presents of activator – benzoil peroxide-amine, being sensible to UV radiation; - corrosion in some spots of the filling. Polimerization self-curing composite resins takes part simultanuosly throug all the volume of the material. Shrinkage of the composites is directed to the centre of the filling. The exemple of self-curing composite resins are: „Evicrol” Spofa-Dental, „Consice” 3M ESPE, „Charisma PPF” Heraeus Kulzer, etc. Control questions to practical lesson

1. Classify composite resins according to the type of polymerization. 2. What are the main demands to composite resins as filling materials? 3. What are the drawbacks of self-curing composites when compared to light-cured composites.

70 4. Is there a necessity to use base materials with self-cured composites. 5. Describe the procedure of filling the carious cavities class I-V with self-cured composite resins. 6. What are the pecularities of polishing of self-cured composite resins. 7. Innumerate some representatives of self-cured composite resins.

1. What is the main difference between self-cured and light- cured composite resins? А. The type of filler В. The type of catalyst С. The type of polymer D. The type of monomers Е. The size of filler particles

2. It is indicated in the instructions for use that composite material Degufill (Degussa) has the size of filler particles 0,4 mcm. To what group of composites belongs this material? А. Light-cured composites В. Microfillers С. Hybrid D. Macrofillers Е. Flowable composites

3. What classes of carious cavities (according to Black’s classification) can be recommended to be filled with Degufill composite resin with size of filler particles 0,4 mcm. А. I-II classes В. III, IV classes

71 С. II-III-IV classes D. III, I, V classes without masticatory load Е. All classes

4. In what time after filling the cavity it is recommended to polish self-cured composite? А. In 8-12 minutes after hardening В. Immediately after hardening С. In 2-3 hours after hardening D. In 24-38 hours after hardening Е. The polishing is not needed

5. Macrofill composites are characterized by great strength, but have not appropriate esthetic properties. What is the reason for low esthetic properties of macrfill composites? А. Inadequate colour shade spectrum В. Low colour stability С. Low colour transparency D. Excessive transparency Е. They can’t be polished

6. Carious cavity of 37 tooth (chronic medium caries) was filled with self-cured composite. What should be the next stage after preparation of caries cavity? А. Placement of the treatment base В. Placement of connecting agent С. Etching of the cavity D. Cleaning of the cavity Е. Placement of the base materials

7. What pastes are used for cleaning of hard tissues before filling the cavity? А. Pastes without fluorine В. Pastes containing Ca and F

72 С. Fluoride-containing tooth-pastes D. Ca-containing tooth pastes Е. Polishing pastes without Ca

8. The selection of the colour of future restoration is choosen: А. In natural illumination and wet surface of the tooth В. Artificial illumination and dry surface of the tooth С. In natural illumination D. In artificial illumination Е. Tooth should be isolated by rubber dam

9. What drills are used for polishing of composite fillings? А. Carbide drills В. Coarse diamomd drills С. Diamond drills with medium grains D. Diamond drills with small grains, carbide drills with 32 blades Е. Carbide drills with 6 blades

10. What substance is used for etching of tooth surface before composite filling? А. Polyacrylic acid В. Ortophosphoric acid С. Citric acid D. Sulphuric acid Е. Hydrochloride acid Reference literature

1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p.

73 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

Theme: Light-curing resin composites. Properties, indications for use, peculiarities of treatment. Compomers.

Polymerization of composites may be achieved by chemical means (self-cure) or by visible-light activation. Dual cure is a combination of light and chemical curing. In chemically activated systems, an organic peroxide initiator (or catalyst), upon reacting with a tertian' amine accelerator, produces free radicals that attack the double bonds of oligomer molecules and begin the process of addition polymerization. Initiation of polymerization in light-activated systems depends on the scission of the initiator molecule, often camphoroquinone, by visible light of appropriate wavelength. In the presence of an aliphatic amine accelerator, free radicals are produced and polymerization begins. For both systems, the following general reaction occurs:

Dimethacrylate + Initiator (peroxide or diketone + blue light) + Accelerator (amine) + Silane-treated particles

74 →Dental composite

Since dimethacrylate oligomers as well as dimethacrylate diluent monomers have reactive double bonds at each end of the molecules, polymerization results in a highly cross-linked polymer. Today's composites designed for restorative applications are supplied as single pastes in opaque, disposable syringes or in color-coded compules for use with a syringe. Light-activated composites are currently the most widely used systems available. Commercially available curing units transmit light from a halogen lamp to the tooth surface by way of a curved quartz rod, a liquid-filled transmission tube, or a bundle of flexible quartz fibers attached to a fiberoptic handpiece. Ultraviolet light is generally filtered out at the light source. The initiator present in most photocuring monomers is camphorquinone. To initiate polymerization, curing lights must emit light within this spectrum, which is in the blue range. Filtered halogen lights produce a broad range of wavelengths within the camphorquinone spectrum and are the standard. Other lights that have higher intensities for faster polymerization have been introduced. These include plasma arc lamps (PAC) and argon laser lights. Although more intense, not all PAC and laser lights have the broad spectrum of the halogen lamps. It is important to match the spectrum of a PAC light to the product being used. The PA 430 has been found to be more effective for certain resin products. Lasers are still in the development stage due to their narrow spectrum. Halogen curing lights are available with continuous operation and programmed cycles. One program is called a stepping function, which cycles the light on and off to reduce possible overheating of the tooth. As with ultraviolet light used in early curing units, blue

75 light has the potential to cause retinal damage. Protective eyewear during operation of curing units is also available and recommended. The setting time and the depth of cure of light-initiated materials depend on the intensity and penetration of the light beam. Polymerization is approximately 75% complete at 10 minutes after exposure to blue light, and curing continues for a period of at least 24 hours. At 24 hours, up to 30% of double bonds still remain unreacted. Polymerization in both chemically and light-activated composites is incomplete. Degrees of conversion are reported to be in the range of 60% to 75%. The number of unreacted double bonds at 24 hours is higher in light-activated than in chemically activated systems and results from a number of factors affecting depth of cure. Light intensity at the surface and time of exposure are critical. The tip of the light source should be held within 3 to 4 mm of the surface in order to cure a light shade of material to a depth of 2.0 to 2.5 mm using a standard exposure time of 40 seconds. A longer exposure time will increase the degree of polymerization at all depths and is a necessity when using darker shades or more opaque materials. A reduction in thickness of the increment to be cured is a more reliable way of achieving polymerization than is an increase in exposure time. In addition, hardness of the top surface of a cured restoration is not a good indication of the extent of polymerization at the bottom surface. Depth of cure is also influenced by the wavelength of light and the concentration of the activator-initiator system. The refractive indices of the resin and filler, as well as the size, shape, and number of filler particles, are important to the dispersion of the light beam. The small, highly numerous colloidal-sized particles of mi-crofilled composites scatter incident light very efficiently, necessitating a longer exposure

76 time to obtain adequate polymerization. Chemically activated systems are considered to have an infinite depth of cure. Manipulation. Placement. Eugenol inhibits the polymerization of resin composites. Therefore, liners, bases, and interim restorations containing eugenol are not recommended. The use of cavity varnish is not recommended under composite restorations, because monomers present in the composite may solubilize and disrupt the integrity of the varnish film. Also, varnish will prevent bonding. Following cavity preparation and prior to placement of the composite, a sealing procedure of some type is indicated. If any dentin bonding agent is to be used, the use of a rubber dam is indicated because moisture in exhaled air may interfere with bonding. The dentin is first conditioned according to the manufacturer's directions. Deep preparations may require the placement of a glass-ionomer or resin-modified glass-ionomer liner or base over the dentin. Very deep cavities require pulpal protection in the form of a thin layer of a calcium hydroxide product on the dentin over the pulp. Enamel and dentin are treated strictly according to manufacturer's directions depending on the bonding agent used. Generally, enamel and dentin are etched for 15 seconds using a 35% to 50% phosphoric acid solution or acid gel. High- viscosity gel etchants have the advantage of ease of control of the application to enamel walls. The preparation is thoroughly washed with water for at least 15 seconds to remove all residue. The surface is gently air-dried, at which point the enamel should have an opaque, white appearance. Any contamination by saliva after this step requires re-etching to clean the surface thoroughly. A dentin bonding agent is applied to the clean enamel and dentin according to the manufacturer's directions. The

77 bonding resin should be air-blown gently to ensure a thin film application. Dentin bonding agents work as well on enamel as do enamel bonding agents. While components of bonding systems should not be interchanged, any composite can be used with most bonding agents. A transparent matrix band is sometimes placed for the purpose of contouring the restoration. The composite is best placed in small layers to minimize polymerization shrinkage. Shrinkage per layer placed is less if the tooth-composite bonding area per layer thickness is large. Each layer should be light cured for at least 40 seconds. After curing, a tackv, air- inhibited layer is present, through which the subsequent layer bonds. Microfilled composites require longer exposure times than do fine-particle composites because their colloidal-sized filler particles scatter blue light more efficiently. Finishing. Composites are finished and polished in order to establish a functional occlusal relationship and a contour that is physiologically in harmony with supporting tissues. In addition, proper contour and high gloss give the restoration the appearance of a natural tooth structure. Early composites had large, hard quartz particles. Polishing preferentially removed the resin matrix, leaving filler particles exposed and giving the surface a dull appearance. In addition, quartz has a hardness about 2.5 times that of enamel and is difficult to polish compared to glasses, which have hardness characteristics similar to that of enamel. Particles smaller than about 0.05 pm cannot be detected visually and allow polishing to a high luster. Fine-particle composites have no microfilled particles, are considered to be only semipolishable, and tend to have a rather opaque appearance. The colloidal-sized filler particles of microfilled materials scatter light efficiently, giving these restorations a

78 pleasing esthetic appearance. Hybrid composites are polishable, but are not as translucent as microfilled composites.

1. What substance is used to initiate the polymerization in light-activated composites? 2. On what distance it is necessary to hold the light source from the surface to cure a light shade of material? 3. What is a standard exposure time for hardening of the composite resin? 4. To what depth usually the composite is cured by a standard exposure time? 5. What is the composition of light-curing composites? 6. Enumerate the types of light-curing composites? 7. Describe the process of filling cavity with light-curing composites.

1. The three major components of composite restorative materials are: A. Resin -- Silane -- Filler B. Silane -- Filler -- Bonding System C. Bonding System -- Filler -- Acrylic Resin D. Acid Etchant -- Bonding Agent -- Acrylic Resin E. Acid Etchant -- Bonding Agent -- Filler

2. What is the role of silane in composite? A. Coupling agent B. Bonding agent C. Conditioning agent

79 D. Acid etchant E. Polishing agent

3. Which ONE of the following is NOT a component of bonding agents used with composite restorations? A. Initiator B. Inhibitor C. Reinforcing filler D. Low MW monomer E. BIS-GMA

4. Which ONE of the following methods is NOT used to categorize composite restorations? A. Weight percent filler level B. Volume percent filler level C. Method of matrix activation D. Filler particle size (or distribution) E. Composite shade

5. Earlier generations of composites (macrofills) contained which ONE of the following volume percent levels of filler? A. 30 v/o B. 40 v/o C. 50 v/o D. 60 v/o E. 70 v/o 6. Which ONE of the following products contains the MOST filler? A. Macrofill Composites B. Pit-and-Fissure Sealants C. Microfill Composites D. Heterogeneous Microfills E. Hybrid Composites

80 7. Which ONE of the following products contains ONLY very small filler particles? A. Macrofill Composites B. Midifill Composites C. Minifill Composites D. Microfill Composites E. Hybrid Composites

8. Which one of the following systems is currently NOT used for curing composites? A. Ultraviolet-light curing B. Visible-light curing C. Chemical curing D. Dual curing E. Very high intensity light curing

9. Which one of the following acids is generally recommended for etching? A. Maleic acid B. Polyacrylic acid C. Tartaric acid D. Phosphoric acid E. EDTA

10. In which of the following categories is dentin bonding of critical importance? A. Class III and IV restorations B. Class V and Erosion-Abrasion Restorations C. Class I and II restorations

11. Which ONE of the following does not affect the depth-of- cure of double bonds in composites? A. Method of activation B. Incremental addition 81 C. Post-curing D. Composite Color E. Finishing Procedure

12. What is the reason for choosing a self-curing (or dual curing) composite rather than light-curing one? A. Large size of the restoration B. Poor access for the curing light C. High level of filler content D. Type of filler in the composite E. Ease of finishing

13. What is the minimum acceptable level for visible curing light outputs? A. 50 mW/cm2 B. 150 mW/cm2 C. 300 mW/cm2 D. 550 mW/cm2 E. 1500 mW/cm2

14. Which one of the following materials is not a retarders or inhibitors of chain reaction polymerization? A. Eugenol B. Calcium Hydroxide C. Water D. Air E. Hydroquinone

15. Which ONE of the following materials should not be used as a base or liner below a composite resin restoration? A. Zinc Oxide Eugenol Cement B. Calcium Hydroxide Cement C. Zinc Phosphate Cement D. EBA Modified ZOE Cement

82 E. Polycarboxylate Cement

16. What is the main reason for avoiding the use of green stones, white stones, or coarse diamond burs for finishing a composite? A. Heat generation B. Battering of enamel margins C. Poor abrasivity D. Scratch width E. Discoloration of the composite

17. What range of scratches would be considered FINE finishing? A. 100-1000 μm B. 10-100 μm C. 1 -10 μm D. 0.1-1 μm E. 0.01-0.1 μm

18. Which ONE of the following "finishing" procedures produces the smoothest surface on a composite? A. Talc B. Soflex discs C. Finishing strips D. Fine diamonds E. Carbide burs

19. Which ONE of the following "finishing" procedures produces the smoothest surface on a composite? A. Talc B. Finishing strips C. Diamond finishing burs D. Carbide burs E. Diamond finishing pastes

83 20. What is the primary problem resulting from polymerization shrinkage? A. Marginal gap formation and microleakage/staining B. Separation of the filler and matrix phases C. Markedly increased water absorption D. More rapid occlusal wear E. Matrix discoloration

21. What is the typical level of polymerization shrinkage for most dental composites? A. < 0.25 % B. 0.25-2.0% C. 2.5-4.0 % D. 6.0-10 % E. 10-12 %

22. What is depth-of-cure possible for an A2 shade of hybrid composite ? A. 5-10 mm B. 4-5 mm C. 2-3 mm D. 1-2 mm E. 1 mm

23. What do dental composites produce when they undergo superficial decomposition over long times? A. Monomers B. Formaldehyde and water C. Acrylic acid D. Bisphenol-A E. Oligomers

84 1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

Theme: Filling of the caries cavity of the I and V classes according to Black classification. Substantiation of the choice of the filling material.

The indication for an initial Class I amalgam restoration is carious tooth structure in the occlusal surface (or in facial or lingual pits in posterior teeth) detected clinically and with bite- wing radiographs. The objectives of treatment are eliminate caries lesions, to remove any enamel that has been undermined by the caries process, to preserve as much sound tooth structure as possible, and to create a strong restoration that mimics the original sound tooth structure and allows little or no marginal leakage. Traditionally, in Class I amalgam preparation, occlusal fissures, or at least those in the developmental grooves, have been included in the preparation, even when

85 caries has not extended throughout the fissures. Additionally, extension of cavity preparations through grooves in which there are no fissures is contraindicated. The preparation is widened to give access to all carious dentin and to remove any enamel not supported by sound dentin. The preparation should be widened only enough to obtain enamel margins supported by sound dentin. Although the outline form should not contain sharp angles, sound tooth structure should not be removed simply to obtain wide, smooth curves in the outline form. The outline form should be smooth to facilitate the uncovering of the margins during carving of amalgam. That is, the margins of the preparation should not be jagged or rough, because it is difficult for the dentist to know whether a restoration margin appears to be irregular because the enamel margin is rough or because amalgam extends post the margins onto the surface of the tooth (overextended amalgam or amalgam flash). When replacing a defective restoration or a restoration associated with a recurrent caries lesion, the outline form will be determined by several factors. First, the outline form of the old restoration will have a major influence. Also, the outline form may have to be extended because of additional pathosis. Finally, the resistance form for the tooth structure or restoration may have to be improved, and that will affect the outline form. To provide retention form for the amalgam, opposing walls of Class I osslusal restorations should be parallel to each other or shoul converge occlusally. Enamel rods in most areas of the occlusal surface are directed roughly parallel to the long axis of the tooth, a factor that should be considered when the angulation of the margin of the amalgam preparation is designed. To enhance their ability to resist fracture, enamel margins should be prepared at a 90-degree or more obtuse angle; enamel margins of less than 90 degrees are much more

86 subject to fracture. Occlusal amalgam restorations should have an occlusogingival thickness of at least 1.5 mm, and preferably 2.0 mm, to resist fracture during function. Placement of amalgam. The technique for amalgam placement is basically the same regardless of the type or classification of the preparation. Amalgam is mixed, carried to the cavity preparation, and condensed into the preparation so that voids are eliminated and all areas of the preparation are filled. The amalgam is then carved to reproduse the portion of the tooth that is missing. Spherical alloys produce an amalgam that requires a lower mercury-alloy ratio and less condensation force. However, the direction of the condensing force is extremely important for spherical amalgams. They do not adapt to the cavity walls as well as lathe-cut or admixture amalgams. Sperical amalgams are said to be less condensable, and lateral condensation is even more important when spherical amalgams are used than when conventional or admixture amalgams are used. The spherical materials generally have a shorter working time and demonstrate a faster set than the admixtures. Class V lesions are those carious and noncarious defects found in the gingival third of facial and lingual tooth surfaces. Class V carious lesions are produced by bacterial plaque attaching to the surface of teeth and producing demineralization. But the etiology of noncarious class V lesions, estimated to occur in 31% to 6% of the population, is both unclear and controversial. Certainly erosion and abrasion play a part in the formation of some class 5, or cervical lesions, but the role of occlusion, and the formation of defects called abfraction lesions, is less clear. Due to the physical properties of tooth structure and restorative materials, long-term retention of the restoration presents a unique challenge.

87 For any class V restoration, the extend of the restoration should be determined by the extent of the lesion. With carious lesions, all demineralized tooth structure should be removed. Some lesions can be treated without cavity preparation, and others require preparation to obtain adequate retention of the restoration. When adhesive restorative material are used, unsupported enamel should be removed to prevent the potential fracture of weaking enamel margins during or after restoration placement. Many techniques and materials have been developed in an attempt to obtain long-term retention for esthetic materials placed in cervical location. Polymerization shrinkage can cause resin composite to pull away from the tooth restoration interface, leaving an open margin and pathway for microleakage occur. For moderate-size to large restorations, incremental resin composite placement is recommended to decrease the effects of polymerization shrinkage. Frequently, the lesion extends onto the root surface, where no enamel is available for bonding. If bonded restorations are placed with no mechanical , undercut retention and the bonding system is relied on to provide all retention, the opportunity for microleakage at the gingival margin increases. Beveling the gingival margin that ends on cementum may increase microleakage. This microleakage can result in the initiation of caries under the restoration, sensitivity, discoloration, or loss of the restoration. It is this microleakage that has spurred the development of new materials and techniques for Class v restorations. Flowable resin composites have reduced filler particle loading, a lower elastic modulus, and lower fracture toughness relative to traditional resin composites, but their resistance to abrasion compares favorably to hybrid composites. They are often used in Class 5 restorations, and it is thought that, like microfilled resin composites, as the tooth flexes, the less rigid

88 restoration will be more able to accommodate the cavity shape change, and therefore be more difficult to dislodge. After cleansing the tooth surface with pumice, a dentin bonding system is used and light polymerized, and a light- cured flowable resin composite is placed into a defect. The technique is quite simple and the restorations can be highly esthetic, but the material has been available for only a short time, and long- time clinical studies to support the use of flowable composites are not available yet. Glass ionomer has been used successfully in class 5 restorations for many years. The preparation for glass-ionomer restoration is essentially the same as that for resin composite. Tooth structure should be conserved as much as possible. The need for mechanical retention is somewhat controversial. Theoretically, the compatibility between coefficients of thermal expansion of tooth structure and traditional GiC should obviate the need for mechanical retention. However, because of tooth flexure and the relatively low bond strength of traditional glass ionomer to dentin, mechanical retention should be considered. Cavosurface bevels are not recommended for the preparation because glass ionomer is a brittle material that requires bulk. Autocured glass-ionomer materials can be placed into the preparation in one increment until it is slightly overfilled. A precontoured cervical matrix is then placed over the material, and the excess material is allowed to extrude out the sides. The matrix is left in place until the material is set. Autocured glass-ionomer cements are inherently rough materials that do not polish well and require protection from water contamination and desiccation for 7 to 10 minutes after placement to preserve strength and tranclucency. After removal of the matrix, the restoration can be contoured with a scalpel blade, carbide or diamond burs, or discs. The finishing procedure should be performed with water or with the surface

89 of the restoration coated with unfilled resin to provide lubrication and prevent desiccation.

1. What for is rubber dam needed and used? 2. What kind of matrix system you have to use in Class V treatment? 3. What kind of resin composites you have to use in Class V restoration? 4. What kind of resin composites you have to use in Class I restoration? 5. What kind of cement you may use in Class I restoration? 6. What kind of cement you may use in Class V restoration? 7. What material can be used as treatment liner? 8. What material type can be used as liner? 9. What for is etching needed? 10. What for is bonding needed? 11. What for is finishing and polishing needed? 12. What is the shrinkage stress? 13. What is for finishing and polishing can be used? 14. What is the polymerization shrinkage?

1. What materials of the below mentioned are recommended for filling of class V carious cavities: A. Self-cured composites B. Light-cured composites C. Glass-ionimer cements D. Amalgams E. All of the above mentioned

90 2. What materials of the below mentioned are recommended fpr filling of class I carious cavities? A. Microfill composites B. Microhybrid composites C. Zn-phosphate cement D. Sylicate cement E. ZnO-eugenol cement

3. In the indication for use of the composite it is written that the size of particle is less than 0,04 mcm. In what classes of cavities it can be used? A. I-II classes B. III-II classes C. V-I-II classes D. III-V classes E. III-V classes

4. During the filling of carious cavity class I what is the proper seguence of stages: A. rubber dam isolation, etching, bonding, filling B. etching, rubber dam isolation, bonding, filling C. rubber dam isolation, etching, placement of the bose, bonding, filling D. etching, rubber dam isolation, placement of the bose, bonding, filling E. etching, bonding, filling

5. What type of drills is used for final preparation of the filling? A. Diamomnd and carbide drills B. Fine grinded and carbide drills C. Medium grinded diamond drills D. 6-blanded carbide drills

91 E. Course and medium diamond drills

6. The final stage of filling procedure is polishing of the filling. In what time it can be conducted after the placement of the filling of self-curing composite? A. Just after the placement of the filling B. In 8-12 minutes after the placement of the filling C. In 2-3 hours after filling D. In 24-38 hours after filling E. Final polishing is not needed

7. During which stage of treatment the operator should choose the colours of future filling? A. After the preparation of carious cavity B. Before the preparation C. After the placement of isolation base D. After bonding procedure E. After the etching procedure

8. Step by step restoration technigue ebsure: A. Compensation of the occlusal loading B. Before fixation of the filling C. Esthetic restoration D. A+C E. All answer are wrong

9. What type of composite is recommended for Class V usage? A. Macrofilled B. Microfilled C. Minifilled D. Nanohybrid E. Any correct answer

92 10. What type of composite is recommended for Class V usage? A. Macrofilled B. Microfilled C. Minifilled D. Microhybrid E. Any correct answer

11. What type of filling material is recommended for Class V usage? A. Amalgam B. Zink-phosphate cement C. ZOE cement D. Polycarboxylate cement E. No correct answer

12. What type of filling material is recommended for Class V usage? A. Zink-phosphate cement B. ZOE cement C. Compomer D. Polycarboxylate cement E. No correct answer 13. What type of filling material is recommended for Class I usage? A. Amalgam B. Zink-phosphate cement C. ZOE cement D. Polycarboxylate cement E. Any correct answer

14. What types of polishing accessories are recommended for Class I restoration? A. abrasive disk

93 B. abrasive band C. rubber cups D. rubber disks E. abrasive disk, rubber cups and polishing rubber disks

15. What type of polishing accessories is recommended for Class V usage? A. abrasive disk B. abrasive band C. rubber cups D. rubber disks E. abrasive disk, rubber cups and polishing rubber disks

16. What thickness of microhybrid composite layer is recommended for curing in modern Composites? A. Not more than 1 mm B. Not more than 3 mm C. 5 mm D. Not more than 2 mm E. No correct answer

17. What isolation accessories are recommended for Class I restorations? A. Rubber dam B. Cotton balls C. Cords D. All of the answers are correct

18. How long the 37% phosphoric acid should stay on the enamel surface for Class I composite restoration according to total-etch method? A. 10 sec B. 30 sec C. 15 sec

94 D. 20 sec E. 25 sec

19. How long the 37% phosphoric acid should stay on the dentin surface of Class I composite restoration according to total-etch method? A. 10 sec B. 20 sec C. 15 sec D. 25 sec E. 30 sec

20. The modern nanohybrid composite adhesive systems are recommended to polymerize for: A. 10 sec B. 5 sec C. 20 sec D. 40 sec E. Any correct answer

21. What thickness of „Life” (Kerr) treatment liner is recommended? A. Not more than 1.0 mm B. 1.5 mm C. 0.5 mm D. Not less than 2.0 mm E. Any correct answer

22. What thickness of GIC layer according to the sandwich- technique in Class I amalgam restoration is recommended? A. mm B. 0.5 mm C. Reach the EDJ D. Any correct answer

95 23. What thickness of GIC layer according to the sandwich- technique in Class I composite restoration is recommended? A. mm B. 0.5 mm C. Reach the EDJ D. Not less than 1.0 mm E. Any correct answer

1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001. Practical lesson No 31

Theme: Filling of the caries cavity of the II class according to Black classification. Substantiation of the choice of the filling material.

An initial Class II restoration is usually placed a carious lesion is present on proximal surface of a molar or premolar.

96 During removal of carious dentin, the demineralized dentin in the periphery of the preparation (at or near DEJ) should be removed and the outline form should be extended to ensure that the enamel at the margins of the preparation is supported by sound dentin. Carious dentin should be removed with the largest round bur that will fit into the area. After the periphery of the preparation is clear of demineralized tooth structure, the carious dentin near the pulp should be removed. The bur should be rotated very slowly in a low-speed handpiece4; the rotation rotation should be so slow that the individual blades of the bur can be seen as it rotates. The blades of the slowly rotating bur are like multiple spoon excavator blades, but the depth that a blade can penetrate into the carious dentin is limited by the edge angle of the bur and by the depth of each bur blade toward the center of the bur, so the bur will remove only a limited depth of carious dentin during each rotation. During removal of deep carious dentin, this procedure is less likely to result in a pulpal exposure than is the use of a spoon excavator. After the shape of the preparation is roughed out with a bur, hand instruments, such as margin trimmer, may be used to fracture the shell of enamel, to shape the facial, lingual, and gingival walls and margins, and to scrape away any fragile enamel from the margins. The facial and lingual walls of a Class II slot preparation should converge slightly toward the occlusal surface to provide retention form for the restoration. To provide resistance form for the Class II amalgam restoration, the proximal preparation should have a mesiodistal dimension of about 1.5 mm or more. If there is sound dentin supporting occlusal enamel in the fossa adjacent to the marginal ridge, that dentin and enamel should be left intact. If the carious lesion extends from the proximal DEJ deeper into dentin, the demineralized dentin should be removed completely, especially in the areas near the DEJ, and sound dentin should be left in place. The gingival floor of the

97 proximal preparation may be flat and approximately perpendicular to the long axis of the tooth, or it may be curved faciolingually, as determined by the extent and configuration of the carious lesion that necessitated the restoration. The location of the gingival floor, therefore, should be determined by the gingival extent of the carious lesion and\or by the level necessary to provide separation of the gingival margin from the adjacent tooth. The gingival wall, like the facial and lingual walls of the proximal preparation, should form an angle of proximately 90 degrees with the surface of the tooth. Convergence toward the occlusaal surface of the facial and lingual walls of the proximal slot preparation gives retention form to the restoration to keep it from dislodging occlusally. Although, with initial proximal surface caries lesions, it is not often necessary to extend the Class 2 preparation into occlusal grooves, the operator will frequently need to replace an existing restoration that was prepared with an occlusal extension. If the restoration is extended into occlusal grooves, this extension will provide resistance to displacement of the restoration proximally. To provide enough resistance, however, the extension into the occlusal surface must have a faciolingual dimension of at least one fourth the distance between the facial and lingual cusp tips, and the facial and lingual margins of the occlusal extension must be approximately parallel to each other in a mesiodistal direction.

1. What for is etching needed? 2. What for is bonding needed? 3. What for is finishing and polishing needed? 4. What is the shrinkage stress? 5. What is the polymerization shrinkage?

98 6. What is for finishing and polishing can be used? 7. What for is matrix band needed and used? 8. What for is wedge needed and used? 9. What for is cord needed and used? 10. What for is formative ring needed and used? 11. What kind of matrix system you have to use in Class II treatment? 12. What kind of resin composites you have to use in Class II restoration? 13. What kind of cement you may use in Class II restoration? 14. What material can be used as base? 15. What material type can be used as subbase? 16. What material can be used as treatment liner? 17. What material type can be used as liner?

1. What type of composite is recommended for Class II usage? A. Macrofilled B. Microfilled C. Minifilled D. Any correct answer 2. What type of filling material is recommended for Class II usage? A. Amalgam B. Zink-phosphate cement C. ZOE cement D. Polycarboxylate cement E. Any correct answer

3. What accessories are recommended to prevent the formation of butt? A. Wedge

99 B. Matrix bend C. Rings for contouring D. Special tool for contact point formation E. Wedge and matrix band

4. What accessories are recommended for Class II contact point reconstruction? A. Wedge B. Matrix bend C. All of the answers are correct D. Rings for contouring E. Special tool for contact point formation

5. The micro furrow between matrix band and tooth structure in Class II restoration is recommended to fill with: A. Dual-cured composite B. Light-cured flow composite C. Self-cured composite D. No correct answer

6. The micro furrow between matrix band and tooth structure in Class II restoration is recommended to fill with: A. Light-cured flow composite B. Macrofilled composite C. Microfilled composite D. Minifilled composite E. No correct answer

7. What thickness of tooth walls in Class II amalgam restoration is recommended? A. 1.0 mm B. 1.5 mm C. 0.5 mm D. Don’t less than 2.0 mm

100 E. No correct answer

8. What thickness of tooth walls in Class II light-cured composite restoration is recommended? A. Don’t less than 1.0 mm B. Don’t less than 3.0 mm C. Don’t less than 2.0 mm D. Don’t less than 0.5 mm E. No correct answer

9. What type of polishing accessories is recommended for the foemation of proximal walls in Class II restorations? A. abrasive disk B. abrasive band C. rubber cups D. polishing rubber disks E. All of the answers are correct

10. What thickness of flow light-cured composite layer is recommended for usage? A. Not more than 3 mm B. 5 mm C. Not more than 1 mm D. Not more than 2 mm E. No correct answer

11. What isolation accessories are recommended for Class II restorations? A. Rubber dam, cords B. Cotton balls C. Cords D. Cotton balls and rubber dam E. No correct answer

101 12. What isolation accessories are recommended for Class II restorations? A. Rubber dam B. Cotton balls C. Cords D. All of the answers are correct

13. The modern nanohybrid composite enamel shades are recommended to polymerize for: A. 10 sec B. 5 sec C. 20 sec D. 40 sec E. Any correct answer

14. What thickness of „Dycal” (Dentsply) treatment liner is recommended? A. 1.5 mm B. Not more than 1.0 mm C. 0.5 mm D. Not less than 2.0 mm E. Any correct answer

15. The wedges can be produced of: A. Wood B. Metal C. Resin D. Wood and resin E. All of the answers are correct

102 1. S. Hussain. Textbook of Dental Materials // Printed of Gopsan Papers Ltd.– NewDelli, 2004.– 475 p. 2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s Art & Science of Operative Dentistry 4th Edition.– Mosby, 2002.– 947 p. 3. W.J. O’Brien. Dental Materials and their selection // Quintessence Publishing.– Chicago, Berlin, Tokyo, Copenhagen, London, 2002.– 418 p. 4. James B. Summitt, J. William Robbins, Richard S. Schwartz. Fundamentals of Operative Dentistry (second edition) // Quintessence Publishing, 2001.

Theme: Filling of the caries cavity of the III and IV classes according to Black classification

Class III caries is smooth-surface caries found on the proximal surfaces of anterior teeth, usually slightly gingival to the proximal contact, but does not involve the incisal angle of the tooth. A caries-indicated class IV restoration is usually the result of a large class III carious lesion that has undermined the incisal edge. The need for class IV restoration due to traumatic fracture occurs most often among children or young adults.

103 Patients demand superior esthetics from anterior restorations. An esthetic restorative material must simulate the natural tooth in color, translucence, and texture, yet must have adequate strength and wear characteristics, good marginal adaptation and sealing, insolubility and biocompability. Regardless of the result desired, certain basic artistic elements must be considered to ensure an optimally esthetic result. In conservative esthetic dentistry these include: - Shape or form. - Symmetry and proportionality. - Position and alignment. - Surface texture. - Color. - Translucency. By far the most commonly used restorative materials in the anterior part of the mouth are resin-based composites. Outline form for resin composite restorations is determined solely by access and by the extent of the caries lesion. There is no need for extension for prevention, and the removal of sound tooth structure to gain mechanical undercut retention is contraindicated. The lingual approach is preferred for class III restorations, but it is not always possible, depending on the location of the carious lesion. The number of burs for cavity preparation should be kept to a minimum. A #2 round bur or #329 pear-shaped carbide bur in a high-speed handpiece can be used for initial access to the lesion. Initial penetration should be made through the marginal ridge, away from the adjacent tooth surface. The outline form of the preparation is then extended to provide access to the dentinal caries lesion. A larger round bur may be used in the low-speed handpiece to excavate demineralized dentin. Narrow bevels (0.5 to 1.0mm) may be placed on accessible enamel margins to remove fragile enamel, to make margins smooth, and to enhance esthetics if the margin is in a visible location. For placing bevels, a flame-

104 shaped finishing bur, a gingival margin trimmer, or another hand instrument may be used. For class IV carious lesions, the cavity design follows the conventional form of the class III preparation and includes a portion of the incisal edge. Carious tooth structure and weak incisal enamel are removed, and all enamel margins are beveled, with wide bevels placed in the incisal portion of the tooth where the enamel is thicker and the stresses on the restoration are likely to be greater. For fractures, if there is no caries or pulpal involvement, a bevel is often the only preparation necessary. An enamel bevel of at last 1.0 mm should be placed around. Increasing the width of the bevel beyond 1.0 mm can be used to provide no additional strength, but a wider bevel can achive a more harmonious esthetic blend between the resin composite and enamel. Clinical steps for a class III or class IV resin composite restoration: a) Select a shade before initiation of dehydration. b) Place a rubber dam. c) Prewedge if difficulty in achieving proximal contact is anticipated. d) Initiate the cavity preparation by accessing the caries lesion through the marginal ridge. Remove the proximal plate of enamel. Be careful to avoid damaging the adjacent tooth. e) Remove the caries dentin with a round bur in a low-speed handpiece. f) Remove unsupported enamel if appropriate, and place bevels with a finishing bur and\or gingival margin trimmer. g) Etch the enamel. Be careful not to etch the adjacent tooth; protect it with a matrix strip. h) Place the primer and adhesive, following the manufacturer’s instructions. i) light cure as indicated. j) If the preparation is large, place resin composite into the deep areas.

105 k) Light cure for at least 40 seconds l) Place a clear plastic strip or other matrix and wedge. m) Add composite and contour the clear plastic matrix strip to contain the material in the proper shape. n) Light cure for at least 40 seconds o) Remove the wedge and matrix strip, and inspect the restoration for voids. Add composite if necessary. p) Remove gingival flash with a №12 or №12b scalpel blade. q) Remove flash from the other margins, and contour the restoration with a finishing bur, finishing diamond, or abrasive disc. r) Remove the rubber dam. s) Check the occlusion and adjust as necessary. t) Finish and polish with disks, rubber points, etc. u) Apply etchant to surface and margins. Rinse, then apply and cure rebonding resin. Glass-ionomer cement restoration. Because of their anticaries potential, glass-ionomer restorative material may be used in class III for patients with high risk of caries. Preparations for these materials should resemble those for resin composite; no bevels are necessary. Only the tooth structure required to allow access for excavation of the carious dentin should be removed. Because these materials bond to enamel and dentin, the placement of retention grooves or points is not necessary. Control questions to practical lesson

1. What for is matrix band needed and used? 2. What for is wedge needed and used? 3. What for is cord needed and used? 4. What for is etching needed? 5. What for is bonding needed? 6. What for is finishing and polishing needed? 7. What is the shrinkage stress?

106 8. What is the polymerization shrinkage? 9. What kind of matrix system you have to use in Class III treatment? 10. What kind of matrix system you have to use in Class IV treatment? 11. What kind of resin composites you have to use in Class III restoration? 12. What kind of resin composites you have to use in Class IV restoration? 13. What kind of cement you may use in Class III restoration? 14. What kind of cement you may use in Class IV restoration? 15. What material can be used as treatment liner? 16. What material type can be used as liner?

1. What type of composite is recommended for Class III usage? A. Macrofilled B. Microfilled C. Minifilled D. Nanohybrid E. Any correct answer

2. What type of composite is recommended for Class III usage? A. Microhybrid B. Macrofilled C. Microfilled D. Minifilled E. Any correct answer

3. What type of composite is recommended for Class IV usage? A. Macrofilled

107 B. Microfilled C. Microhybrid D. Minifilled E. Any correct answer

4. What type of composite is recommended for Class IV usage? A. Macrofilled B. Microfilled C. Minifilled D. Nanohybrid E. Any correct answer

5. What type of filling material is recommended for Class IV usage? A. Amalgam B. Zink-phosphate cement C. ZOE cement D. Polycarboxylate cement E. Any correct answer

6. What type of filling material is recommended for Class III usage? A. Any correct answer B. Amalgam C. Zink-phosphate cement D. ZOE cement E. Polycarboxylate cement

7. What accessories are recommended for Class III contact point reconstruction? A. Wedge B. Wedge and matrix band C. Matrix bend

108 D. Rings for contouring E. Special tool for contact point formation

8. What accessories are recommended for Class IV contact point reconstruction? A. Wedge B. Matrix bend C. Rings for contouring D. Special tool for contact point formation E. Wedge and matrix band

9. What type of polishing accessories is recommended for Class III and IV usage? A. abrasive disk B. abrasive band C. rubber cups D. All of the answers are correct E. rubber disks

10. What isolation accessories are recommended for Class III and IV restorations? A. Rubber dam B. Cotton balls C. Cords D. All of the answers are correct 11. The composite opaque shades are recommended to polymerize for: A. 10 sec B. 5 sec C. 20 sec D. 40 sec E. Any correct answer

109 12. The composite enamel shades are recommended to polymerize for: A. 10 sec B. 5 sec C. 20 sec D. 40 sec E. Any correct answer

13. What kind of matrix band is recommended for Class III and IV light-cured composite restorations? A. Plastic translucent band B. Metal sectional matrix system C. Metal band D. All of the answers are correct