1. Dental Anomalies in Radiology
王文岑 助理教授
口腔病理影像診斷科 1

2. 學習目標 資料來源 判讀X光片上的牙齒異常 Developmental abnormalities v.s. acquired
Ref 1: White SC, Pharoah MJ. Oral Radiology:
Principles and interpretation 6th ed
Ref 2: Neville BW, Damm DD, Allen CM and Bouquot JE. Oral & maxillofacial patholgy 3nd ed
Ref 3:高醫口腔病理診斷門診病例

3. Supernumerary Teeth (hyperdontia, supplemental teeth)
Developmental Abnormalities
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 cyst
Syndrome:
Cleidocranial dysplasia, Gardner’s syn.
Ref.1 2

4. Ref.3

5. Cleidocranial dysplasia
Ref.3

6. Cleidocranial dysplasia
Lambdoidal suture, mastoid fontanel 未關閉。
Ref.3

7. Cleidocranial dysplasia
Ref.3

8. Cleidocranial dysplasia
Ref.3

9. Cleidocranial dysplasia
Ref.3

10. Missing Teeth 8 > 5 > 2 > 1 3~10%, excluding 3rd molars
Hypodontia
Oligodontia
Anodontia
8 > 5 > 2 > 1
1. Ectodermal
dysplasia;
2. orofaciodigital
syndrome
Ref.1 4

11. Submergence Infraocclusion, Secondary retention,
Reimpaction, Reinclusion
most affect 8~9y/o children and teeth D & E
PDL absent , ankylosis
Occlusal and periodontal problems
Ref.3

12. ectodermal dysplasia
Ref.1

13. Ectodermal dysplasia
Ref.3

14. SIZE OF TEETH Macrodontia
True generalized type and relative type
Macrodontia
Hemangioma, hemihypertrophy of the face, pituitary giantism
Microdontia
pituitary dwarfism
supernumerary teeth, 3rd molars, lateral incisors

15. Macrodontia
Microdontia
Ref.1

16. Transposition Two teeth exchanged positions 3 & 4 ; 3 & 2, 657
ERUPTION OF TEETH
Transposition
Two teeth exchanged positions
3 & 4 ; 3 & 2, 657
Ref.1

17. Transposition
Ref.3

18. Gemination (twinning)
Altered Morphology of Teeth
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
Ref.3
Ref.1 9

19. Fusion (synodontia)
-Adjacent tooth germs combined with dentin or enamel
bifid crown or two recognizable teeth, reduced number of teeth
more common in the primary dentition, esp. anterior region
Ref.1,2 7

20. Concresence - Roots of two or more teeth united by cementum
Fusion after root formation
Traumatic injury or crowding
Pre-extraction x-ray check
maxillary molars; 3rd molar & a supernumerary tooth
Ref.1 8

21. Taurodontism -Longitudinal enlarged pulp chamber,
increased distance between CEJ to
the bifurcation
normal crown size & tooth length, shortened roots
not recognizable clinically
most in molars
Trisomy 21
Ref.1 11

22. Dilaceration A sharp bend or curve in the crown or root
maxillary premolars
Ref.1 12

23. Dens in Dente (dens invaginatus)
- Infolding of the outer enamel surface into the interior
at the anatomically defined pit
caries→pulpal disease
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
Ref.1 13

24. Dens in Dente
radicular type
coronal type
Ref.1
Dilated odontome

25. 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.1
Ref.2 15

26. 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, attrition
2.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

27. Amelogenesis Imperfecta
Hypocalcified type
Hypoplastic type
Ref.1

28. 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

29. Dentinogenesis
Imperfecta
Ref.1

30. Dentin Dysplasia Type I (radicular) rare (1:100,000)
-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

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

32. 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

33. Regional Odontodysplasia
Ref.1

34. 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

35. 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.1
Ref.2

36. 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
Ref.2,3

37. Turner’s tooth (enamel hypoplasia)
Ref.1
Ref.3

38. 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
Hutchinson’s incisors
(screw driver shape)
Ref.1

39. -Physiologic wearing from occlusal contacts
Acquired Pathologic Conditions
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

40. 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

41. Dental Floss Injury
Cervical portion of proximal surfaces just above gingiva
Narrow semilunar R-L, distal surface often deeper than mesial
Ref.1

42. -Chemical action not involving bacteria
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

43. Resorption -Removal of tooth structure by odontoclast
Chronic infection (inflammation), excessive pressure and function, tumors and cysts

44. Internal Resorption
- within the pulp chamber or canal, involves resorption of surrounding dentin, results in enlarged pulp space
Ref.1

45. Internal Resorption
Ref.1

46. 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)

47. Lateral root surface ER
Apical ER
Lateral root surface ER
Ref.1

48. 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

49. 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
Ref.1

50. 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

51. 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

52. Summary DEVELOPMENTAL ABNORMALITIES ACQUIRED PATHOLOGIC CONDITIONS
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 CONDITIONS
Attrition
Abrasion
Tooth brushong injury
Dental floss injury
Erosion
Resorption
Internal resorption
External resorption
Secondary dentin
Pulp stone
Pulpal sclerosis
Hypercementosis