1. Tooth Morphology Review

2. Some general information...

3. Mixed dentition: mix of deciduous and permanent, 6 - 12 yrs

4. Succedaneous teeth: permanent teeth that replace deciduous
Permanent molars are the only teeth not succedaneous
Premolars succeed primary molars
Only succedaneous teeth not having the same name as their primary counterparts

5. Normal eruption sequence (permanent teeth)
Mandibular teeth precede maxillary counterparts
Mandibular teeth erupt in anterior to posterior order
Maxillary arch: maxillary canine erupts after premolars (last succedaneous tooth to erupt)

6. Permanent Eruption Sequence
1. Mandibular first molar: yrs
2. Maxillary first molar: yrs
3. Mandibular central incisor: yrs
4. Mandibular lateral incisor: yrs
5. Maxillary central incisor: yrs
6. Maxillary lateral incisor: yrs

7. 7. Mandibular canine: 9 - 10 yrs
8. Mandibular first premolar: yrs
9. Maxillary first premolar: yrs
10. Mandibular second premolar: yrs
11. Maxillary second premolar: yrs
12. Maxillary canine: yrs
13. Mandibular second molar: yrs
14. Maxillary second molar: yrs
15. Mandibular third molar: yrs
16. Maxillary third molar: yrs

8. Notes: Mandibular central is first succedaneous tooth to erupt
Maxillary canine is last succedaneous tooth to erupt
Premolars are the only succedaneous teeth having a different name than their deciduous counterpart
Root completion is generally yrs after eruption

9. Know the following terms:
Cusps
Tubercles (mini cusps)
Cingulum
Ridges
Marginal ridges
Triangular ridges
Transverse ridges
Oblique ridge
Cusp ridges
Incline planes

10. Mammelons
Fossa
Developmental groove
Supplemental groove
Pit
Contact area
Developmental lobe

11. Lobes: All anterior teeth have 4 lobes Premolars:
3 labial
1 lingual
Premolars:
3 lobes for facial cusp
1 or 2 lobes for lingual cusp(s)
Lobes of molar teeth correspond to the number of major cusps

12. Crown surface geometric outline forms:
Triangular
Trapezoidal
Rhomboidal

13. Facial and Lingual surfaces:
All have trapezoidal geometric form

14. Mesial and Distal surfaces:
Anteriors: triangular
Maxillary posteriors: trapezoidal
Mandibular posteriors: rhomboidal

15. Contact areas: Central incisors: mesial contacts mesial
Aids in stabilizing arch form
Prevention of food impaction
Aids food flow pattern
Become larger over time

16. Notes: Contacts become more cervical from anterior to posterior
Distal contact usually more cervical than mesial (exception: mandibular 1st premolars & mandibular centrals)
Anterior contacts centered (F-L)
Posterior contacts are facial to center (F-L)

17. Embrasures:
Incisal (occlusal) embrasures increase in size from anterior to posterior
Cervical (gingival) embrasures decrease in size from anterior to posterior
Labial and lingual embrasures nearly equal in anteriors
Lingual embrasures larger than labials in posteriors

18. Facial and lingual heights of contour:
Facially: cervical third for ALL teeth
Lingually:
Anteriors: cervical third
Posteriors: middle third (exception: occlusal third for mand 2nd premolar)

19. Curvature of CE line: Curvature usually greater on mesial than distal
Curvatures become flatter from anterior to posterior

20. Important Characteristics of Tooth Types

21. Maxillary Central Incisor
Crown is almost as wide as it is long
Only incisor where MD = IC (almost)
Contact area
Mesial: incisal third
Distal: near junction of incisal and middle third

22. Mesial CEJ has greatest depth of curvature of any tooth
Facial CEJ flatter curvature than other anteriors
Incisal view roughly triangular

23. Notes: (max central) 1. M-D widest of all anteriors
2. M-D nearly as wide as I-C
3. M-D is wider than F-L (other anteriors are wider F-L than M-D, except maxillary lateral )
4. Cross-section at cervical is triangular

24. Maxillary Lateral Incisor:
Smaller, more rounded than central
Root length almost as long
Greater variation in form (except 3rd molars)
Sometimes missing congenitally

25. Maxillary Lateral… Incisally more rounded than other incisors
Lingual-gingival groove and lingual pit common
Contact area
Mesial: incisal 1/3 near junction of incisal and middle third
Distal: junction of incisal and middle third (most cervical of the incisors)

26. Notes: (max lateral)
1. Incisal edge contour is more rounded than any other incisor
2. Most likely to have lingual pit of all incisors
3. Lingual fossa and marginal ridges more prominent than other incisors
4. DI corner most rounded of all incisal corner
5. MD close to FL dimension (MD>FL)

27. Mandibular Incisors: Simplest, least variable teeth
Proximal view: Incisal edge is lingual to long axis of tooth
Lateral has distal twist to crown
Contact areas:
Mesial and distal: incisal third
Bifurcated root sometimes found

28. Notes: (mand incisors)
Mandibular Central Incisor
Bilaterally most symmetrical
M and D contact areas both at same level in incisal third
Root shortest of anterior teeth
One wear facet on incisal edge
Mandibular Lateral Incisor
DI corner visible from mesial view
Distal contact area more lingual than mesial contact area

29. Maxillary Canine: Crown + root length = longest tooth
Last succedaneous tooth to erupt
Facial/lingual view: pentagonal (5-sided)
Contact areas:
Mesial: junction of incisal and middle third
Distal: middle third (most cervical of the anteriors)

30. Proximal view: cusp tip is just facial to mid-line of root
MI cusp ridge shorter than DI
Presence of labial and lingual ridges
Cingulum more pronounced than mandibular
Single root is longest of any tooth

31. Notes: (max canine)
1. Crown length nearly as long as maxillary central’s
2. Two lingual fossae - ML and DL separated by lingual ridge
3. Root is longest of all teeth
4. Largest F-L of anteriors

32. Mandibular Canine: Narrower MD than maxillary
Mesial outline is straight line
MI cusp ridge shorter than DI
Cusp tip located lingual to proximal long axis
Bifurcated root sometimes found
Contact areas:
Mesial: incisal third
Distal: junction of incisal and middle third

33. Notes: (mand canine)
1. Crown longer than maxillary canine (longest crown in the mouth)
2. Longest root in mandibular arch
3. Total length almost the same as maxillary canine
4. M and D height of contours more incisal than maxillary canine
5. Facial outline “moon-shape”

34. Maxillary Premolars: Crowns are wider FL than MD
2 cusps, nearly equal size
1st is little larger than 2nd

35. Maxillary 1st Premolar:
Occlusal outline is hexagonal
Facial outline is pentagonal
Contact areas:
Mesial: junction of occlusal and middle third; facial to mesial marginal groove
Distal: more cervically and facially located than mesial
MF cusp ridge is longer than DF
Facial cusp tip offset to distal
Lingual cusp tip offset to mesial

36. Lingual cusp of 1st is shortest of maxillary premolars
Pronounced mesial concavity
Pronounced mesial marginal groove
More angular than 2nd
M and D pits further apart longer central groove
Less secondary grooves than 2nd

37. Root structure of max 1st premolar:
Type I - single root with 2 pulp canals
Cross section is kidney shaped, mesial indented
Type II - bifurcated root with root trunk (most common)
Type III - laminated root
Cross section is hour-glass
Trifurcated roots sometimes found: 2 buccal, 1 lingual

38. Notes: (max 1st premolar)
1. MB cusp ridge longer than DB cusp ridge (similar to primary max canine)
2. Buccal cusp tip located distal to tooth midline
3. Lingual cusp shortest of maxillary premolar cusps, tipped mesially
4. Strong mesial crown/root concavity

39. 5. Mesial marginal ridge shorter than distal marginal ridge
6. Cervical cross-section is kidney shape
7. Two canals (F and L) -
lingual has larger pulp canal
facial pulp canal is longer (facial cusp taller)

40. Maxillary 2nd Premolar:
Smaller in all dimensions than 1st
More rounded crown form
F and L cusps nearly equal in height
Lingual cusp tip offset mesially
No mesial concavity

41. More rounded than 1st
M and D pits closer - shorter central groove
More supplemental grooves
Normally single root, bifurcation possible

42. Notes: (max 2nd premolar)
1. F and L cusps more equal
2. M and D halves more symmetrical than other premolars
3. Distal root surface has deeper depression

43. Mandibular Premolars:
1st is smaller than 2nd
FL and MD dimensions about equal
F cusp more prominent than L
Crown profile tilts towards lingual
Normally single rooted, bifurcation possible

44. Mandibular 1st Premolar:
Looks and functions more like canine
Lingual cusp non-functional
M and D height of contour in middle third (distal possibly more occlusal*)
Lingual cusp tip offset to mesial
Presence of ML developmental groove

45. Occlusal view: rounded diamond shape
Distal fossa circular, mesial fossa linear
Mesial marginal ridge slopes at 45o, distal ridge is horizontal
Single root, bifurcation possible (F and L roots)

46. Notes: (mand 1st premolar)
1. Both M and D height of contours at middle third (with distal possibly even more occlusal)
2. Only premolar with a ML groove
3. Proximal view - buccal cusp tip centered over root midline (unique of all premolars)
4. Pronounced transverse ridge separating M and D fossae

47. 5. Mesial marginal ridge inclined. more than other premolar
5. Mesial marginal ridge inclined more than other premolar marginal ridges, more cervical than distal marginal ridge
6. Buccal cusp occupies more of the occlusal surface than other premolars

48. Mandibular 2nd Premolar:
Larger than 1st mand premolar
2 forms: 2 cusps and 3 cusps
Y type groove (3 cusps) most common
3 pits: M, D, and central
Lingual groove present
No transverse ridge
U and H type grooves (2 cusps)
2 pits, M and D
Transverse ridge present

49. Resembles small molar: marginal ridges horizontal
Lingual height of contour at occlusal third (unique)
Single root, bifurcation possible (F and L)
Sometimes congenitally missing

50. Notes: (mand 2nd premolar)
1. Buccal cusp ridges less steeply inclined than other premolars
2. Lingual height of contour at occlusal third (unique)
3. Three occlusal patterns: Y, U, H

51. 4. Y-shape type: 3 cusps 5 developmental lobes Possible lingual groove
3 pits, 3 fossae (M, C, D)
No true transverse ridge
Lingual M-D width possibly wider than facial width*

52. 5. Two-cusp pattern: (U and H shape)
4 developmental lobes
Lingual cusp tipped mesially
No lingual groove
2 pits, 2 fossae
Transverse ridge present
More lingual taper than 3-cusp type

53. Permanent Molars:
1st molars are cornerstones in development of occlusion
Crowns are largest and most complex
3 - 5 cusps
Multi-rooted

54. Maxillary Molars: Crowns wider FL than MD
Oblique ridge and DL groove unique
3 roots: lingual, MB and DB
4 cusps: ML, MB, DB, DL

55. Maxillary 1st Molar: Largest tooth in maxillary arch
Shorter O-C than premolars
Contact areas:
Mesial: junction of occlusal and middle third
Distal: middle third
Distal cervical crown/root concavity
MB root oftentimes has 2 canals; apex inline with MB cusp tip

56. ML cusp largest (ML>MB>DB>DL)
Cusp of Carabelli on ML cusp
Distal view: all 4 cusps visible
Mesial view: only 2 cusps visible

57. Occlusal view: rhomboidal form
MB and DL corners acute angle
DB and ML corners obtuse
Wider MD on lingual than buccal
V-shape CE dip toward bifurcation on facial surface

58. Notes: (max 1st molar) 1. Largest tooth in maxillary arch
2. Largest crown in mouth, largest F-L dimension of any tooth
3. Least variable in anatomic form
4. Presence of a facial bucco-gingival ridge running mesiodistally
5. Lingual width possibly wider than facial width

59. 6. Pronounced distal cervical concavity
7. Oblique ridge about same height as marginal ridges
8. Three pits and four fossae
9. Palatal (lingual) root wider M-D than F-L
10. MB root might have pulp canals: MB and ML canals

60. Maxillary 2nd Molar: Smaller than 1st, esp. M-D 2 crown forms:
Rhomboidal (like 1st)
Heart-shaped (smaller DL cusp)

61. Notes: (max 2nd molar)
1. Two crown forms: rhomboidal and heart-shape (diminished DL cusp)
2. MB root apex is inline with buccal groove

62. Maxillary 3rd Molar: Smallest molar in mouth
Most variation in crown and root form of any maxillary tooth
Most often congenitally missing

63. Notes: (max 3rd molar) 1. Most variable anatomic form of all teeth
2. Shortest O-C crown of any tooth
3. Shortest roots of any tooth

64. Brain overload…
…all the best tomorrow!

65. Mandibular Molars: MD wider than FL Rectangular occlusal outline
4 - 5 cusps
2 lingual cusps same size

66. Mandibular 1st Molar: 1st permanent tooth to erupt
Largest tooth of mandibular arch
5 cusps: MB>ML>DL>DB>D
Contact areas:
Mesial: junction of occlusal and middle third
Distal: junction of occlusal and middle third

67. CE sometimes dips towards bifurcation on facial
No transverse ridges(?)
3 fossae: central, mesial, distal
2 roots: mesial larger than distal
Mesial has 2 root canals (MB & ML)
3 roots sometimes: MB, ML, D

68. Notes: (mand 1st molar)
1. Facial surface is largest surface of any tooth
2. CE line more occlusal on lingual than buccal i.e. root length is longer on lingual than buccal
3. Mesial root has 2 pulp canals: MB & ML

69. 4. Distal surface of M root and. mesial surface of D root have
4. Distal surface of M root and mesial surface of D root have deeper root depressions (inner surfaces of both roots)
5. May exhibit 3 roots:
2 mesial (MB, ML) roots
1 distal root

70. Mandibular 2nd Molar: 4 cusps: MB largest
Occlusal anatomy simplest of any molar
Most symmetrical of molars
2 transverse ridges
Root form similar to 1st

71. Mandibular 3rd Molar: Variable in size and shape:
Type I: crown similar to 2nd molar
Type II: crown similar to 1st molar (5 cusps)
Often congenitally missing

72. Pulp morphology: Functions of pulp: Formation of dentin Nutrition
Sensation
Defense and protection (reparative dentin)

73. Some things to remember:
Outline of pulp cavity follows external contour of tooth
Roots with round cross section possess one canal
Roots with oval or elongated cross section often more than one canal

74. Lateral (accessory) canals: lateral canals found in the apical third
Supplementary canal: canal in excess of normal number of canals
Anastomosis: canal branch that connects horizontally between canals

75. Know anatomical root forms of each tooth type, esp. in cross-section
Comparative widths (M-D vs F-L)
Shapes (e.g. oval, round, triangular, etc)
Number of pulp canals

76. Maxillary Central Incisor:
Newly erupted central has 3 pulp horns
Pulp chamber wider MD than FL
Cervical cross section, pulp outline triangular

77. Maxillary Canine: Pulp cavity wider FL than MD (oval)
Root canal longest in mouth

78. Maxillary 1st Premolar:
Wider FL than MD
2 roots (F and L), 2 canals
Buccal pulp horn larger (larger F cusp)
Lingual pulp canal larger diameter
Cervical cross section is kidney shape

79. Maxillary 1st Premolar

80. Maxillary 1st Molar: 3 roots, 3 - 4 canals MB often has 2 canals (70%)
Lingual root/canal largest - wider ML than FL

81. Mandibular Canine:
Sometimes has two roots and two canals (F and L)

82. Mandibular 1st Premolar:
1-2 pulp horns, larger buccal, smaller/diminished lingual
2 roots and 2 canals possible (F and L)

83. Mandibular 1st Molar: 2 roots, mesial (larger) and distal
3 canals (70%) MB, ML, and D

84. Deciduous Dentition
Some unique features...

85. Maxillary Central (primary)
1. No mamelons
2. M-D crown width greater than I-C width (only anterior tooth, primary or permanent, with this characteristic)

86. Maxillary Canine (primary)
1. M & D contacts at same level
2. M-D and I-C dimensions similar
3. Mesial cusp ridge longer than D cusp ridge (similar to max 1st premolar)

87. Maxillary 1st Molar (primary)
1. Crown does not resemble any other molar - appears more like a premolar
2. Facial CE line dips prominently towards mesial
3. No root trunk

88. Maxillary 2nd Molar (primary)
1. Larger than primary 1st max molar
2. Most closely resembles permanent 1st maxillary molar
3. Presence of Carabelli cusp
4. No root trunk

89. Mandibular 1st Molar (primary)
1. Crown unlike any other tooth, primary or permanent
2. Facial CE line dips prominently towards mesial
3. Facial cervical ridge has strong mesial bulge

90. 4. Pronounced mesial transverse ridge
5. Mesial and central pits, no distal pit
6. No root trunk

91. Mandibular 2nd Molar (primary)
1. Closely resembles permanent 1st mandibular molar
2. No root trunk

92. That’s Enough for Today!!!