developmental disturbances of the teeth

DEVELOPMENTAL

DISTURBANCES OF THE TEETH

Prepared by:Dr. Rea Corpuz

(1) Size

(2) Number and Eruption

(3) Shape/Form

(4) Defects of Enamel and Dentin

Developmental Disturbances

Microdontia

Macrodontia

Size

Microdontia

(1) True Generalized Microdontia

(2) Relative Generalized Microdontia

(3) Focal or Localized Microdontia

Size

all teeth are smaller than normal

occur in some cases of pituitary dawrfism

exceedingly rare

teeth are well formed

(1) True Generalized Microdontia

normal or slightly smaller than normal teeth

are present in jaws that are somewhat larger than normal

(2) Relative Generalized Microdontia

common condition

affects most often maxillary lateral incisior + 3rd molar

these 2 teeth are most often congenitally missing

(3) Focal/Localized Microdontia

common forms of localized microdontia is that which affects maxillary lateral incisior

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


Microdontia

Macrodontia

Size

Macrodontia

(1) True Generalized Macrodontia

(2) Relative Generalized Macrodontia

(3) Focal or Localized Macrodontia

Size

all teeth are larger than normal

associated with pituitary gigantism

exceedingly rare

(1) True Generalized Macrodontia

normal or slightly larger than normal teeth in small jaws

results in crowding of teeth

insufficient arch space

(2) Relative Generalized Macrodontia

uncommon condition

unknown etiology

usually seen with mandibular 3rd molars

(3) Focal/Localized Macrodontia

(1) Size


(3) Shape/Form



Supernumerary

Anodontia

Impaction

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

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

Number and Eruption

Supernumerary

Mesiodens

Fourth molar

•Maxillary Paramolar• Distomolar or Distodens

Mandibular Premolar

Maxillary lateral incisors

Number and Eruption

Supernumerary

Mandibular central incisors

Maxillary Premolars

Number and Eruption

most common supernumerary tooth

tooth situated between maxillary central incisors

singly

paired

erupted or impacted

inverted

Mesiodens

small tooth

cone-shaped crown

short root

Mesiodens

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

Fourth Molar

small + rudimentary

situated bucally or lingually to one of the maxillary molars

interproximally between 1st

+ 2nd or 2nd + 3rd maxillary molars

Paramolar

molar located distal to molar

Distomolar/Distodens

Supernumerary

Anodontia

Impaction

Number and Eruption

Anodontia

lack of tooth development

absence of teeth

Number and Eruption

Anodontia

Complete Anodontia

Partial Anodontia • Hypodontia• Oligodontia

Pseudoanodontia

False Anodontia

Number and Eruption

when all teeth are missing

rare

often associated with a syndrome known as hereditary ectodermal dysplasia

Complete Anodontia

lack of development of one or more teeth

Hypodontia

lack of development of six or more teeth

Oligodontia

when teeth are absent clinically because of impaction or delayed eruption

Pseudoanodontia

when teeth have been exfoliated or extracted

False Anodontia

Supernumerary

Anodontia

Impaction

Number and Eruption

Impaction

most often affects the mandibular 3rd molars + maxillary canines

less commonly:• premolars• mandibular canines• second molars

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

Number and Eruption

Impaction

Ankylosis

Number and Eruption

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

Ankylosis

(1) Size


(3) Shape/Form



Crown

Root

Shape and Form

Crown

Fusion

Gemination

Taurodontism

Talon’s Cusp

Leong’s Cusp

Shape and Form

Crown

Dens Invaginatus

Peg-shaped Lateral

Hutchinson Incisor

Mulberry Molar

Shape and Form

Root

Concresence

Enamel Pearl

Dilaceration

Flexion

Ankylosis

Shape and Form

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

Fusion

Fusion

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

Gemination

variation in tooth form:

elongated crowns

apically displaced furcations

• resulting in pulp chambers that have apical occlusal height

Taurodontism

may bee seen as isolated incident in families

associated with syndromes such as

Down syndrome

Klinefelter’s syndrome

Taurodontism

little clinical significance

No treatment is required

Taurodontism

Talon’s Cusp

Leung’s Premolar

Dens Evaginatus

well-delineated additional cusp

located on the surface of an anterior tooth

extends at least half the distance from CEJ to incisal edge

Talon’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

Leung’s Cusp

deep surface invagination of crown or root that is lined by enamel

2 forms:

coronal radicular

Dens Invaginatus (Dens in Dente)

depth varies from slight enlargement of cingulum to a deep infolding that extends to apex

historically, it has been classified into 3 major types:

Type I Type II Type III


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


Type III

• extends through the root• perforates in the apical or lateral radicular area without any immediate communication with pulp


undersized lateral incisor

smaller than normal

occurs when permanent lateral incisors do not fully develop

Peg-Shaped Lateral

Peg-Shaped Lateral

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

Hutchinson’s Incisor

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

Mulberry Molar

Root

Concresence

Enamel Pearl

Dilaceration

Flexion

Ankylosis

Shape and Form

2 fully formed teeth

joined along the root surfaces by cementum

noted more frequently in posterior and maxillary regions

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 roentgenographic 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

Concrescence

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

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

Enamel Pearls

may cause stagnation at gingival margin but, if they contain pulp, this will be exposed when pearl is removed

Enamel Pearls

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

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

Dilaceration

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

Flexion

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

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

Ankylosis

(1) Size


(3) Shape/Form



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


affects both dentition

deciduous permanent

classified based on pattern of inheritance:

hypoplasia hypomaturation hypocalcified


No treatment except for improvement of cosmetic appearance


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


dentin + pulp chambers appear normal

no treatment is necessary


enamel is normal in form on eruption but:

opaque white to brownish-yellow softer than normal tends to chip from underlying dentin

Hypomaturation Amelogenesis Imperfecta

Radiographically:

affected enamel exhibits radiodensity similar to dentin

Hypomaturation 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

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

Hypocalcified Amelogenesis Imperfecta

also known as “Hereditary Opalascent Dentin”

due to clinical discoloration of teeth

mutation in the dentin sialophosphoprotein

affects both primary + permanent dentition

Dentinogenesis Imperfecta

have blue to brown discoloration

with distinctive translucence

enamel frequently separates easily from underlying defective dentin


Radiographically:

bulbous crowns cervical constriction thin roots early obliteration of roots canals + pulp chambers


Treatment:

prevent loss of enamel + subsequent loss of dentin through attrition

cast metal crowns on posterior

jacket crowns on anterior teeth


Classification:

Type I Type II Type III


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

Type I 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

Type II 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

Type III Dentinogenesis Imperfecta

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)

Dentin Dysplasia

both dentitions are of normal color

periapical lesion

premature tooth loss may occur because of short roots or periapical inflammatory lesions


Radiographically:

roots are extremely short pulps almost completely obliterated periapical radiolucencies:• granulomas• cysts• chronic abscesses


color of primary dentition is opalescent

permanent dentition is normal

coronal pulps are usually large (thistle tube appearance)

filled with globules of abnormal dentin


Radiographically:

(Deciduous) roots are extremely short pulps almost completely obliterated

(Permanent) abnormally large pulp chambers in coronal portion of tooth


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


teeth affected may exhibit a delay or total failure in eruption

shape is altered, irregular in appearance


Radiographically:

marked reduction in radiodensity teeth assume a “ghost” appearance both enamel + dentin appear very thin pulp chamber is exceedingly large


Treatment:

poor cosmetic appearance of teeth extraction with restoration by prosthetic appliance


normal thickness enamel

extremely thin dentin

enlarged pulps

thin dentin may involve entire tooth or be isolated to the root

most frequently in deciduous

Shell Tooth

References:References:

BooksBooks

Cawson, R.A: Cawson’s Essentials of OralCawson, R.A: Cawson’s Essentials of Oral Oral Pathology and Oral Medicine,Oral Pathology and Oral Medicine, 88thth Edition Edition

• (pages 24-36)(pages 24-36) Neville, et al: Oral and Maxillofacial PathologyNeville, et al: Oral and Maxillofacial Pathology 33rdrd Edition Edition

• (pages 77-113)(pages 77-113) Regezi, Joseph et al: Oral Pathology, Clinical Regezi, Joseph et al: Oral Pathology, Clinical Pathological CorrelationsPathological Correlations

55thth Edition Edition• (pages 361-373)(pages 361-373)

Shafer, et al: A textbook of Oral Pathology,Shafer, et al: A textbook of Oral Pathology, 33rdrd Edition Edition• (pages 37-69)(pages 37-69)

developmental disturbances of the teeth

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