12/7/2015
DEVELOPMENTAL DISTURBANCES OF THE TEETH
Dr. Ibtisam Briek SENUSSI Oral pathology
19.11.2015
Developmental Disturbances
(1) Size
(2) Number and Eruption
(3) Shape/Form
(4) Defects of Enamel and Dentin
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Size
Microdontia
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Size
Microdontia
(1) True Generalized Microdontia
(2) Relative Generalized Microdontia
(3) Focal or Localized Microdontia
(1) True Generalized Microdontia
All teeth are smaller than normal
Occur in some cases of pituitary dawrfism
Exceedingly rare
Teeth are well formed
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(2) Relative Generalized Microdontia
Normal or slightly smaller than normal teeth
Are present in jaws that are somewhat larger than normal
(3) Focal/Localized Microdontia
Common condition
Affects most often maxillary lateral incisior + 3rd molar
These 2 teeth are most often congenitally missing
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(3) Focal/Localized Microdontia
Common forms of localized microdontia is that which affects maxillary lateral incisor
Peg lateral Instead of parallel or diverging mesial + distal surfaces sides converge or taper together incisally forms cone-shaped crown root is frequently shorter than usual
Macrodontia
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Size
Macrodontia
(1) True Generalized Macrodontia
(2) Relative Generalized Microdontia
(3) Focal or Localized Macrodontia
(1) True Generalized Macrodontia
All teeth are larger than normal
Associated with pituitary gigantism
Exceedingly rare
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(2) Relative Generalized Macrodontia
Normal or slightly larger than normal teeth in small jaws
Results in crowding of teeth
Insufficient arch space
(3) Focal/Localized Macrodontia
Uncommon condition
Unknown etiology
Usually seen with mandibula3rd molars
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Developmental Disturbances
(1) Size
(2) Number and Eruption
(3) Shape/Form
(4) Defects of Enamel and Dentin
Number and Eruption
Supernumerary
Impaction
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Number and Eruption
Supernumerary Results from continued proliferation of permanent or primary dental lamina to form third tooth germ
Teeth may have: • normal morphology • rudimentary • miniature
Number and Eruption
Supernumerary
More often in permanent dentition than primary dentition
More in the maxilla than in mandible
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Number and Eruption
Supernumerary
May be impacted erupted or impacted
Because of additional tooth bulk, it causes:
• Malposition of adjacent teeth
• Prevent their eruption
Number and Eruption
Supernumerary
Many are impacted
• Characteristically found in cleidocranial dysostosis
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Number and Eruption
Number and Eruption
Supernumerary Mesiodens
Fourth molar • Maxillary Paramolar • Distomolar or Distodens
Mandibular Premolar
Maxillary lateral incisors
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Number and Eruption
Supernumerary
Mandibular central incisors
Maxillary Premolars
Mesiodens
Most common supernumerary tooth
Tooth situated between maxillary central incisors Singly , Paired , Erupted or impacted , Inverted
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Mesiodens
Small tooth Cone-shaped crown Short root
Para-molar
Small + rudimentary
Situated bucally or lingually to one of the maxillary molars
Interproximally between 1st + 2nd or 2nd + 3rd maxillary molars
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Distomolar / Distodens
Molar located distal to molar
Fourth Molar
2nd most common Situated distal to 3rd molar Small rudimentary tooth, but may be of normal size Mandibular 4th molar also is seen occasionally, but less common than maxillary molar
Distomolar
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Number and Eruption Anodontia
lack of tooth development
absence of teeth
Number and Eruption
Anodontia
Complete Anodontia
Partial Anodontia • Hypodontia • Oligodontia
Pseudoanodontia
False Anodontia
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Complete Anodontia
When all teeth are missing
Rare
Often associated with a syndrome known as hereditary ectodermal dysplasia
Hypodontia
Lack of development of one or more teeth
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Oligodontia
Lack of development of six or more teeth
Pseudo - Anodontia
When teeth are absent clinically because of impaction or delayed eruption.
False Anodontia
When teeth have been exfoliated or extracted
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Number and Eruption
Impaction
most often affects the mandibular 3rd molars + maxillary canines
less commonly: • premolars • mandibular canines • second molar
Number and Eruption
Impaction
Occurs due to obstruction from crowding
From some other physical barrier
Occasionally, may be due to an abnormal eruption path, presumably because of unusual orientation of tooth germ
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Number and Eruption
Impaction
Ankylosis
Ankylosis
fusion of a tooth to surrounding bone
with focal loss of periodontal ligament, bone + cementum become inextricably mixed
cause fusion of tooth to alveolar bone
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Developmental Disturbances
(1) Size
(2) Number and Eruption
(3) Shape/Form
(4) Defects of Enamel and Dentin
Shape and Form Crown
Root
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Shape and Form
Crown
Fusion
Gemination
Talon’s Cusp
Leong’s Cusp
Shape and Form
Crown
Peg-shaped Lateral
Hutchinson Incisor
Mulberry Molar
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Shape and Form
Root
Concresence
Flexion
Ankylosis
Fusion Joining of 2 developing tooth germs
Resulting in a single large tooth structure
May involve entire length of teeth
Or may involve roots only, in which case cementum + dentin are SHARED
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Fusion
Gemination
Fusion of 2 teeth from a single enamel organ Partial cleavage Appearance of 2 crowns that share same root canal Trauma has been suggested as possible cause, the cause is still unknown
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Taurodontism
Variation in tooth form:
Elongated crowns
Apically displaced furcations • Resulting in pulp chambers that have apical occlusal height
Taurodontism
May be seen as isolated incident in families
Associated with syndromes such as
Down syndrome
little clinical significance
No treatment is required
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Dens Evaginatus
Talon’s Cusp
Leung’s Premolar
Talon’s Cusp
Well-delineated additional cusp
Located on the surface of an anterior tooth
Extends at least half the distance from CEJ to incisal edge
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Leung’s Cusp
Developmental condition
Clinically as an accessory cusp or a globule
Located on occlusal surface between buccal + lingual cusps of premolars
Unilaterally or bilaterally
Dens Invaginatus (Dens in Dente)
Deep surface invagination of crown or root that is lined by enamel
2 forms: Coronal Radicular
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Dens Invaginatus (Dens in Dente)
Depth varies from slight enlargement of cingulum to a deep in-folding that extends to apex
Historically, it has been classified into 3 major types:
Type I Type II Type III
Dens Invaginatus (Dens in Dente)
Type I
• Confined to the crown
Type II • Extends below cemento-enamel junction • Ends in a blind sac • May or may not communicate with adjacent dental pulp
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Dens Invaginatus (Dens in Dente)
Type III
• Extends through the root • Perforates in the apical or lateral radicular area without any immediate communication with pulp
Peg-Shaped Lateral
Undersized lateral incisor Smaller than normal Occurs when permanent lateral incisors do not fully develop
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Hutchinson’s Incisor
Characteristic of congenital syphilis
Lateral incisors are peg-shaped or screwdriver-shaped
Widely spaced
Notched at the end
With a crescent-shaped deformity
Hutchinson’s Incisor
Notches on their biting surfaces
Named after Sir Jonathan Hutchinson
English surgeon + pathologist who 1st described it
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Mulberry Molar
Dental condition usually associated with congenital syphilis Characterized by multiple rounded rudimentary enamel cusps on permanent 1st molars
Mulberry Molar Dwarfed molars with cusps covered with globular enamel growths Giving the appearance of a mulberry
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Shape and Form
Root
Concresence
Enamel Pearl
Dilaceration
Flexion
Ankylosis
Concrescence
2 fully formed teeth
Joined along the root surfaces by cementum
Noted more frequently in posterior and maxillary regions
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Concrescence
often involves a 2nd molar tooth in which its roots closely approximate the adjacent impacted 3rd molar
may occur before or after the teeth have erupted
usually involves only 2 teeth
Concrescence
Diagnosis can frequently be established by routine graphic examination
Often requires no therapy unless union interferes with eruption; then surgical removal may be warranted
Since with fused teeth, extraction of one may result in extraction of the other
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Enamel Pearls
Droplets of ectopic enamel
Or so called enamel pearls
May occasionally be found on roots of teeth
Uncommon, minor abnormalities, which are formed on normal teeth
Enamel Pearls
Occur most commonly in bifurcation or trifurcation of teeth
May occur on single-rooted premolar as well
Maxillary molars are commonly affected than mandibular molars
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Enamel Pearls
Consist of only a nodule of enamel attached to dentin.
May have a core of dentin containing pulp horn.
May be detected on radiographic examination.
May cause stagnation at gingival margin but, if they contain pulp, this will be exposed when pearl is removed
Dilaceration
Angulation or a sharp bend or curve in root or crown of a formed tooth
Trauma to a developing tooth can cause root to form at an angle to normal axis of tooth
Rare deformity
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Dilaceration
Movement of crown or of the crown and part of root from remaining developing root may result in sharp angulation after tooth completes development
Dilaceration
Hereditary factors are believed to be involved in small number of cases
Eruption generally continues without problems
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Flexion
Deviation or bend restricted just to the root portion
Usually bend is less than 90 degrees
May be a result of trauma to the developing tooth
Ankylosis
Also known as “submerged teeth”
Fusion of a tooth to surrounding bone
Deciduous teeth most commonly mandibular 2nd molars Undergone variable degree of root resorption
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Ankylosis Have become ankylosed to bone
This process prevents their exfoliation + subsequent replacement by permanent teeth
After adjacent permanent teeth have erupted, ankylosed tooth appears to have submerged below level of occlusion
THANKS
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N ATAL T EETH
These are extra teeth that are present at birth. Cause:
A developmental disturbance creating intracellular activity during the first stage of tooth development (bud stage) can result in the development of extra teeth.
The most common natal teeth are lower incisors.
19.11.15
19.11.15 Natal Teeth Treatment: These teeth are defective and their removal is generally recommended, particularly if mobility poses a threat of aspiration. These teeth also make feeding difficult.
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19.11.15 NEONATAL TEETH
These are primary teeth that erupt prematurely (during the first few weeks of life).
Cause:
Premature tooth eruption.
19.11.15 Neonatal Teeth
Treatment These teeth are usually normal primary teeth and should be retained. An x-ray will be taken if possible to confirm that these are not extra teeth.
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Shape and Form 19.11.15
• Supernumerary Roots
• Accessory roots are most commonly seen in mandibular canines, premolars and molars ( especially third molar). • Very rare in maxillary anterior teeth & mandibular incisors. • Discovered in routine radiographic examination . • This condition important in extraction of teeth and RCT.
Developmental Disturbances
(1) Size
(2) Number and Eruption
(3) Shape/Form
(4) Defects of Enamel and Dentin
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Amelogenesis Imperfecta
also known as:
Hereditary Enamel Dysplasia Hereditary Brown Enamel Hereditary Brow Opalescent Teeth
Amelogenesis Imperfecta
group of conditions caused by defects in the genes encoding enamel matrix proteins
genes that encode for enamel proteins:
amelogenin mutated in enamelin in patients others with this condition
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Amelogenesis Imperfecta
affects both dentition
deciduous permanent
classified based on pattern of inheritance:
hypoplasia hypomaturation hypocalcified
Amelogenesis Imperfecta
No treatment except for improvement of cosmetic appearance
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Hypoplastic Amelogenesis Imperfecta inadequate formation of matrix
enamel is randomly:
pitted grooved or very thin hard + translucent
defects become stained but teeth are not especially susceptible to caries unless enamel is scanty and easily damaged
Hypoplastic Amelogenesis Imperfecta
reduced enamel thickness
abnormal contour absent interproximal contact points
Radiographically:
enamel reduced in bulk shows thin layer over occlusal + interproximal surfaces
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Hypoplastic Amelogenesis Imperfecta
dentin + pulp chambers appear normal
no treatment is necessary
Hypomaturation Amelogenesis Imperfecta
enamel is normal in form on eruption but:
opaque white to brownish-yellow softer than normal tends to chip from underlying dentin
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Hypomaturation Amelogenesis Imperfecta
Radiographically:
affected enamel exhibits radiodensity similar to dentin
Hypocalcified Amelogenesis Imperfecta
enamel matrix is formed in normal quantity
poorly calcified
when newly erupted:
enamel is normal in thickness normal form but weak opaque or chalky in appearance
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Hypocalcified Amelogenesis Imperfecta
with years of function:
coronal enamel is removed except for cervical portion that is occasionally calcified better
Radiographically:
density of enamel + dentin are similar
Dentinogenesis Imperfecta
also known as “Hereditary Opalascent Dentin”
due to clinical discoloration of teeth
mutation in the dentin sialophosphoprotein
affects both primary + permanent dentition
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Dentinogenesis Imperfecta
have blue to brown discoloration
with distinctive translucence
enamel frequently separates easily from underlying defective dentin
Dentinogenesis Imperfecta
Radiographically:
bulbous crowns cervical constriction thin roots early obliteration of roots canals + pulp chambers
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Dentinogenesis Imperfecta
Treatment:
prevent loss of enamel + subsequent loss of dentin through attrition
cast metal crowns on posterior
jacket crowns on anterior teeth
Dentinogenesis Imperfecta
Classification:
Type I Type II Type III
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Type I Dentinogenesis Imperfecta
occurs in families with Osteogenesis Imperfecta
primary teeth are more severely affected than permanent teeth
Type I Dentinogenesis Imperfecta
Radiographically:
partial or total obliteration of pulp chambers + root canals by continued formation of dentin roots may be short + blunted cementum, periodontal membrane + bone appear normal
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Type II Dentinogenesis Imperfecta
never occurs in association with osteogenesis imperfecta unless by chance
most frequently referred to as hereditary opalascent dentin
only have dentin abnormalities and no bone disease
Type II Dentinogenesis Imperfecta
Radiographically:
partial or total obliteration of pulp chambers + root canals by continued formation of dentin roots may be short + blunted cementum, periodontal membrane + bone appear normal
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Type III Dentinogenesis Imperfecta
“Bradwine type”
racial isolate in Maryland
multiple pulp exposures in deciduous not seen in type I or II
periapical radiolucencies
Type III Dentinogenesis Imperfecta
enamel appears normal
large size of pulp chamber is due not to resorption but rather to insufficient + defective dentin formation
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Dentin Dysplasia
also known as “Rootless Teeth”
rare disturbance of dentin formation
normal enamel
atypical dentin formation
abnormal pulpal morphology
hereditary disease
Dentin Dysplasia
Classification:
Type I (Radicular Type)
Type II (Coronal Type)
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Type I (Radicular Type)
both dentitions are of normal color
periapical lesion
premature tooth loss may occur because of short roots or periapical inflammatory lesions
Type I (Radicular Type)
Radiographically:
roots are extremely short pulps almost completely obliterated periapical radiolucencies: • granulomas • cysts • chronic abscesses
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Type II (Coronal Type)
color of primary dentition is opalescent
permanent dentition is normal
coronal pulps are usually large (thistle tube appearance)
filled with globules of abnormal dentin
Type II (Coronal Type)
Radiographically:
(Deciduous) roots are extremely short pulps almost completely obliterated
(Permanent) abnormally large pulp chambers in coronal portion of tooth
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Regional Odontodysplasia
also known as:
Odontogenic Dysplasia Odontogenesis Imperfecta Ghost Teeth
Regional Odontodysplasia
one or several teeth in a localized area are affected
maxillary teeth are involved more frequently than mandibular area
etiology is unknown
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Regional Odontodysplasia
teeth affected may exhibit a delay or total failure in eruption
shape is altered, irregular in appearance
Regional Odontodysplasia
Radiographically:
marked reduction in radiodensity teeth assume a “ghost” appearance both enamel + dentin appear very thin pulp chamber is exceedingly large
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Regional Odontodysplasia
Treatment:
poor cosmetic appearance of teeth extraction with restoration by prosthetic appliance
Shell Tooth
normal thickness enamel
extremely thin dentin
enlarged pulps
thin dentin may involve entire tooth or be isolated to the root
most frequently in deciduous
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References:
Books
Cawson, R.A: Cawson’s Essentials of Oral Oral Pathology and Oral Medicine, 8th Edition • (pages 24-36) Neville, et al: Oral and Maxillofacial Pathology 3rd Edition • (pages 77-113) Regezi, Joseph et al: Oral Pathology, Clinical Pathological Correlations 5th Edition • (pages 361-373) Shafer, et al: A textbook of Oral Pathology, 3rd Edition • (pages 37-69)
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