1. Dental Anomalies in Radiology
Developmental VS. acquired 1

2. Developmental Abnormalities

3. 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. 2

5. Cleidocranial dysplasia

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

11. Q: 請就以上同一名患者的根尖X光片,說明有何異常。

12. ectodermal dysplasia

13. 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

14. Macrodontia
Microdontia

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

16. Altered Morphology of Teeth

17. Gemination, Fusion, Concrescence

18. 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 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 7

20. Concresence - Roots of two or more teeth united by cementum
space restriction during develop., local trauma, excessive occlusal force or local infection after development
maxillary molars; 3rd molar & a supernumerary tooth 8

21. 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 10

22. 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 11

23. Dilaceration A sharp bend or curve in the crown or root
maxillary premolars 12

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

25. 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 14

26. radicular type
Dilated odontome

27. 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 15

28. Lingual pits
Dens Evaginatus

29. Amelogenesis Imperfecta
-Disturbance in enamel development
Normal dentin & root
autosomal dominant or recessive , X-linked
Four general types 16

30. 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

31. 2.Hypomaturation
normal thickness of enamel, but mottled surface; cloudy white, yellow or brown, opaque in color
softer than normal
same density as dentin

32. 4.Hypomaturation-hypocalcified with taurodontism
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

33. Amelogenesis Imperfecta

34. 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

35. Dentinogenesis
Imperfecta
Osteogenesis imperfecta

36. 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

37. Dentinogenesis
Imperfecta

38. Dentin Dysplasia rare (1:100,000) Type I (radicular)
-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 fill in before eruption
20 % of teeth with type I disease have apical radiolucencies

39. Dentin Dysplasia

40. 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

41. Dentin Dysplasia

42. 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

43. Regional Odontodysplasia

44. 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

46. 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

47. 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

48. Turner tooth

49. 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

50. Congenital syphilis
Hutchinson’s incisors & mulberry molars

51. Acquired Pathologic Conditions

52. 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

53. Abrasion -Nonphysiologic wearing by contact with foreign substances
Factitious habits or occupational hazards
tooth brushing, flossing, pipe smoking, opening hairpins with teeth

54. Tooth Brushing Injury V-shaped groove in cervical area Sensitive
Maxillary premolars >canines > incisors
R-L defect at cervical level, well-defined semilunar shapes

55. Attrition
Tooth Brushing Injury

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

57. -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
R-L defect on the crown

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

59. Internal Resorption
- within the pulp chamber or canal, involves resorption of surrounding dentin, results in enlarged pulp space
Maybe related to inflammation of pulp tissues--acute trauma to tooth, pulp capping, pulpotomy…
1>6>7; M>F, commonly begins during 30-50y/o
Pink spots

60. 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

61. Internal Resorption

62. 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)

63. Apical ER:
-blunting with normal bone and lamina dura
-root shortening, except due to periapical inflammatory lesions
*canal is visible and abnormal wide at apex
Lateral root surface ER:
-presence of an unerupted adjacent tooth

64. Apical ER
Lateral root surface ER

65. 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

66. 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

67. 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

68. 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

69. Hypercementosis