WenChen Wang

Dental Anomalies in

Radiology

王文岑 助理教授 口腔病理影像診斷科

wcwang@kmu.edu.tw

WenChen Wang

學習目標 判讀 X光片上的牙齒異常 Developmental abnormalities v.s. acquired

資料來源 Ref 1: White SC, Pharoah MJ. Oral Radiology: Principles and interpretation 6th ed. 2009. Ref 2: Neville BW, Damm DD, Allen CM and Bouquot

JE. Oral & maxillofacial patholgy 3nd ed. 2009. Ref 3:高醫口腔病理診斷門診病例

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

Developmental Abnormalities

Ref.1

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Ref.3

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Cleidocranial dysplasia

Ref.3

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Cleidocranial dysplasia

Ref.3

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Cleidocranial dysplasia

Ref.3

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Cleidocranial dysplasia

Ref.3

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Cleidocranial dysplasia

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Missing Teeth 3~10%, excluding 3rd

molars Hypodontia Oligodontia Anodontia 8 > 5 > 2 > 1 1. Ectodermal dysplasia; 2. orofaciodigital syndrome

Ref.1

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Submergence

most affect 8~9y/o children and teeth D & E

PDL absent , ankylosis

Occlusal and periodontal problems

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Ref.3

Infraocclusion, Secondary retention,Reimpaction, Reinclusion

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ectodermal dysplasia

Ref.1

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Ectodermal dysplasia

Ref.3

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SIZE OF TEETH True generalized type and relative

type

Macrodontia Hemangioma, hemihypertrophy

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

lateral incisors

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Macrodontia Microdontia

Ref.1

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ERUPTION OF TEETH

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

Ref.1

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Transposition

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Ref.3

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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

Altered Morphology of Teeth

Ref.1

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Ref.3

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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

Ref.1,2

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Concresence

Fusion after root formation Traumatic injury or crowding Pre-extraction x-ray checkmaxillary molars; 3rd molar & a supernumerary tooth

- Roots of two or more teeth united bycementum

Ref.1

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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

Ref.1

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Dilaceration

- A sharp bend or curve in the crown or root

maxillary premolars

Ref.1

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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 diseasecoronal 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

Ref.1

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radicular type

Dilated odontomeRef.1

Dens in Dente

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coronal type

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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

Ref.1Ref.2

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Amelogenesis Imperfecta-Disturbance in enamel development Normal dentin & root autosomal dominant or recessive , X-linked

1.Hypoplastic type Thin enamel with pitted, rough or smooth & glossy surface; yellowish

to brown undersized, squared crown, lack of contact flat occlusal surface & low cusps, attrition2.Hypomaturation

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

softer than normal same density as dentin

3.Hypocalcified type normal thickness of enamel, density less than dentin normal size & shape when erupt, abrade or fracture away rapidly permeability increase, darkened & stained

4.Hypomaturation-hypocalcified with taurodontism

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Amelogenesis Imperfecta

Ref.1

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Hypocalcified typeHypoplastic type

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Dentinogenesis Imperfecta (hereditary opalescent dentin)

Autosomal dominant hereditary Type I : DI + OI (osteogenesis imperfecta) COL1A1, COL1A2 Type II : Isolated DI. (1/8000) DSPP Type III: DI of the Brandywine type * DSPP

A racial isolate in Maryland, DI + multiple pulp exposures in deciduous teeth

enamel fractures, attrition severely dark brown to black

Radiographic Features of D.I. : bulbous crown, normal size, constriction of the cervical

area short & slender roots, occlusal attrition partial or complete obliteration of the pulp chambers, root

canals absent or threadlike

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Dentinogenesis Imperfecta

Ref.1

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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 little or no trauma

short or abnormal root shaped, pulp chamber & root canals completely filled in before eruption

20 % of teeth with type I disease have apical radiolucencies

Ref.1

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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

Ref.1

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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

Ref.1

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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. molar and buccal or lingual in Mand. molars

Ref.1

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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

with supernumerary tooth

Ref.1Ref.2

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Turner’s Hypoplasia (Turner’s tooth)

-a type of enamel hypoplasia

- 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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Ref.2,3

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Turner’s tooth(enamel hypoplasia)

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Ref.1

Ref.3

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Congenital Syphilis

30 % p’t develop dental hypoplasia

Hutchinson’s incisors & mulberry molars

not all p’t with Hutchinson’s teeth or mulberry molars will have congenital syphilis

Ref.1

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Hutchinson’s incisors (screw driver shape)

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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 chamber & canals

Abrasion

-Nonphysiologic wearing by contact with foreign substances

Factitious habits or occupational hazards

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

Acquired Pathologic Conditions 39

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Tooth Brushing Injury

V-shaped groove in cervical area

Sensitive Maxillary premolars

>canines > incisors R-L defect at cervical

level, well-defined semilunar shapes

Ref.1 Ref.3

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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

Ref.1

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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

Radiolucent 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,

involves resorption of surrounding dentin, results in enlarged pulp space

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Ref.1

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Internal Resorption

Ref.1

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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

Lateral root surface ER

Ref.1

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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

Ref.1

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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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Ref.1

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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

Ref.1

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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 with lamina dura and PDL space

Ref.1

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Summary

DEVELOPMENTAL ABNORMALITIESDEVELOPMENTAL ABNORMALITIES

NUMBER OF TEETH SIZE OF TEETH ERUPTION OF TEETH ALTERED MORPHOLOGY OF TEETH

Fusion(synodontia) Concresence Gemination(twinning) Taurodontism Dilaceration Dens in dente (dens invaginatus) Dens evaginatus Amelogenesis imperfecta Dentinogenesis imperfecta Dentin dysplasia Enamel pearl Talon cusp Turner’s hypoplasia (Turner’s

tooth) Congenital syphilis

ACQUIRED PATHOLOGIC ACQUIRED PATHOLOGIC CONDITIONSCONDITIONS

Attrition Abrasion Tooth brushong injury Dental floss injury Erosion Resorption Internal resorption External resorption Secondary dentin Pulp stone Pulpal sclerosis Hypercementosis

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