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
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Cleidocranial dysplasia
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Cleidocranial dysplasia
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Cleidocranial dysplasia
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Cleidocranial dysplasia
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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
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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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Infraocclusion, Secondary retention,Reimpaction, Reinclusion
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ectodermal dysplasia
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Ectodermal dysplasia
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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
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ERUPTION OF TEETH
Transposition Two teeth exchanged positions 3 & 4 ; 3 & 2, 657
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Transposition
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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
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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
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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 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
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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
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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
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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
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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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31Dentin 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. molar 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
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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Turner’s tooth(enamel hypoplasia)
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Ref.1
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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
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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
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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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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
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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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
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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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