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Dental Anomalies in

Radiology

Developmental VS. acquired

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Developmental

Abnormalities

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Supernumerary Teeth (hyperdontia, supplemental teeth)

1~4% , familial tendency Mesiodens, paramolar Distodens, distomolar teeth Peridens Single : premaxilla, maxillary molar Multiple : premolar area, mandibular

M : F = 2 : 1 Impaction or delay eruption of normal teet

h; dentigerous cystSyndrome: Cleidocranial dysplasia, Gardner’s syn.

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Cleidocranial dysplasia

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Missing Teeth

3~10%, excluding 3rd molars Hypodontia Oligodontia Anodontia 8 > 5 > 2 > 1 Ectodermal dysplasia ; oro

faciodigital syndrome

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Q: 請就以上同一名患者的根尖 X光片 ,說明有何異常。

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ectodermal dysplasia

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SIZE OF TEETH True generalized type and relative typ

e

Macrodontia Hemangioma, hemihypertrophy

of the face, pituitary giantismMicrodontia pituitary dwarfism supernumerary teeth, 3rd molars,

lateral incisors

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Macrodontia Microdontia

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ERUPTION OF TEETH

Transposition Two teeth exchanged positions 3 & 4 ; 3 & 2, 657

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Altered Morphology of Teeth

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Gemination, Fusion, Concrescence

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Gemination (twinning)

-Division of a single tooth bud

primary dentition , esp. incisor region

complete twinning increase tooth number

pulp chamber is single & enlarged, maybe partial divided

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Fusion (synodontia)

bifid crown or two recognizable teeth, reduced number of teeth

more common in the primary dentition, esp. anterior region

-Adjacent tooth germs combined with dentin or enamel

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Concresence

space restriction during develop., local trauma, excessive occlusal force or local infection after development

maxillary molars; 3rd molar & a supernumerary tooth

- Roots of two or more teeth united bycementum

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Fusion / Gemination

A tooth with two separated root canals and with one or two roots…Fusion

An enlarged tooth with a bifid crown containing an enlarged or possibly partially divided pulp chamber…Gemination

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Taurodontism

normal crown size & tooth length, shortened roots

not recognizable clinically

most in molars Trisomy 21

-Longitudinal enlarged pulp chamber, increased distance between CEJ to the bifurcation

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Dilaceration

- A sharp bend or curve in the crown or root

maxillary premolars

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Dens in Dente(dens invaginatus)

- Infolding of the outer enamel surface into the interior

at the anatomically defined pit

caries→pulpal disease

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coronal type: enamel organ infolding into the dental papilla; 2>1>4,5>3

radicular type: invagination of Hertwig’s epithelial root sheath, lined with cementum;

4, 7

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radicular type

Dilated odontome

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Dens Evaginatus

- Outfolding of enamel organ a tubercle on occlusal surface, with

enamel surface & dentin core, pulp horn often extends into the evagination

premolar or molar pulp infection due to fracture

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Dens Evaginatus

Lingual pits

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Amelogenesis Imperfecta

-Disturbance in enamel development

Normal dentin & root autosomal dominant or recessive ,

X-linked Four general types

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Thin enamel with pitted, rough or smooth & glossy surface; yellowish to brown

undersized, squared crown, lack of contact

flat occlusal surface & low cusps, attrition

1.Hypoplastic type

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2.Hypomaturation

normal thickness of enamel, but mottled surface; cloudy white, yellow or brown, opaque in color

softer than normal same density as dentin

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normal thickness of enamel, density less than dentin

normal size & shape when erupt, abrade or fracture away rapidly

permeability increase, darkened & stained

3.Hypocalcified type

4.Hypomaturation-hypocalcified with taurodontism

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Amelogenesis Imperfecta

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Dentinogenesis Imperfecta (hereditary opalescent dentin)

autosomal dominant hereditary

Type I : D.I. + osteogenesis imperfecta

Type II : D.I., no skeletal defects enamel fractures, attrition severely dark brown to black

WenChen WangOsteogenesis imperfecta

Dentinogenesis Imperfecta

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bulbous crown, normal size, constriction of the cervical area

short & slender roots occlusal attrition partial or complete obliteration of th

e pulp chambers, root canals absent or threadlike

Radiographic Features of D.I.

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Dentinogenesis Imperfecta

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Dentin Dysplasia

-autosomal dominant disturbance rare (1:100,000)

Type I (radicular) normal color & shaped in both dentition malaligned arch, drifting and exfoliate with lit

tle or no trauma short or abnormal root shaped, pulp chamber &

root canals completely fill in before eruption 20 % of teeth with type I disease have apical ra

diolucencies

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Dentin Dysplasia

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TypeII (coronal)

primary dentition appears as D.I., but permanent dentition is normal

obliterated of the pulp chamber & reduced root canals after eruption

roots are normal in shape & proportion

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Dentin Dysplasia

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Regional Odontodysplasia (odontogenesis imperfecta)

- hypoplastic & hypocalcified of both dentin & enamel

only a few adjacent teeth in a quadrant affected either primary or permanent teeth

central incisors > lateral incisors >canines (maxillary)

delayed eruption ghostlike appearance in image large pulp chamber & wide root canals, roots

are short & poorly outlined thin enamel , less dense as usual

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Regional Odontodysplasia

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Enamel Pearl (enameloma, enamel drop, enamel nodule)

- small globule of enamel on the roots furcation area of molars

prevalence : 3 % mesial or distal aspect in Max. mo

lar and buccal or lingual in Mand. molars

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Talon Cusp - Anomalous hyperplasia

of the cingulum of a Max. or Mand. incisor →a supernumerary cusp

T shaped in incisal view Differential diagnosed w

ith supernumerary tooth

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Turner’s Hypoplasia (Turner’s tooth)

-a local hypoplastic or hypomineralized defect in crown of a permanent tooth

extension of a periapical infection or mechanical trauma from deciduous predecessor

most common in lower premolars

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Turner tooth

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Congenital Syphilis

30 % p’t develop dental hypoplasia Hutchinson’s incisors & mulberry m

olars not all p’t with Hutchinson’s teeth or

mulberry molars will have congenital syphilis

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Congenital syphilis Hutchinson’s incisors & mulberry molars

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Acquired Pathologic Conditions

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Attrition

-Physiologic wearing from occlusal contacts

Incisal, occlusal and interproximal surfaces(contact points)

Depends on the abrasiveness of diet, salivary factors, mineralization, emotional tension

Bruxism--pathologic condition Crown shorten, reduction of pulp chambe

r & canals

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Abrasion

-Nonphysiologic wearing by contact with foreign substances

Factitious habits or occupational hazards

tooth brushing, flossing, pipe smoking, opening hairpins with teeth

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Tooth Brushing Injury V-shaped groove in cerv

ical area Sensitive Maxillary premolars >ca

nines > incisors R-L defect at cervical le

vel, well-defined semilunar shapes

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Attrition

Tooth Brushing Injury

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Dental Floss Injury

Cervical portion of proximal surfaces just above gingiva

Narrow semilunar R-L, distal surface often deeper than mesial

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Erosion

-Chemical action not involving bacteria Contact acid with teeth: 1. chronic vomiting or acid reflux from GI disorders 2. consumes large amounts of acid foods 3. occupational exposure Regurgitated acids attack lingual surfaces;

diet--labial; industrial–all surfaces R-L defect on the crown

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Resorption

-Removal of tooth structure by odontoclast

Chronic infection (inflammation), excessive pressure and function, tumors and cysts

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Internal Resorption - within the pulp chamber or canal, involve

s resorption of surrounding dentin, results in enlarged pulp space

Maybe related to inflammation of pulp tis

sues--acute trauma to tooth, pulp cappin

g, pulpotomy…

1>6>7; M>F, commonly begins during 3

0-50y/o

Pink spots

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Radigraphs reveal symptomless early lesions of IR

R-L, round, oval, or elongated within root or crown and continuous with pulp chamber or canal

Sharply defined and smooth or slightly scalloped …irregular widening of the pulp chamber or canal

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Internal Resorption

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External Resorption

-outer surface of tooth resorbed, most commonly in root surface

Localized inflammatory lesions, reimplanted teeth, tumor & cyst, excessive mechanical(orthodontic) and occlusal forces, impactions

Common sites : apical & cervical (lateral root surface)

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Apical ER: -blunting with normal bone and lami

na dura -root shortening, except due to peri

apical inflammatory lesions

*canal is visible and abnormal wide at apex

Lateral root surface ER: -presence of an unerupted adjacent

tooth

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Apical ER

Lateral root surface ER

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Secondary Dentin - Dentin deposited in pulp

chamber after primary dentin formatted completely

Normal aging process tertiary dentin: pathologic

condition after chronic trauma

Reduction in size of pulp chamber and canals

Begins in the region adjacent to source of stimuli and alters normal shape of chamber

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Pulp Stone

-- Foci of calcification in the pulp

R-O within pulp chambers or root canals or extending from pulp chamber into root canals, most common in molars

No uniform shape or number

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Pulpal Sclerosis

- Diffuse calcification in pulp chamber and canals

Correlation strongly with age

Generalized, ill defined collection of fine RO throughout pulp chamber and canals

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Hypercementosis -Excessive deposition of cementum on roots 1.supraerupated tooth after opposing tooth loss 2.periapical inflammatory lesions 3.hyperocclusion or fractured 4.Paget’s disease 5.hyperpituitarism Smooth or irregular enlargement of root wit

h lamina dura and PDL space

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Hypercementosis