1. Tooth Morphology Basics
Howard Chi, D.M.D.

2. Learning Objectives
• Primary and permanent dentition
• Tooth identification system
• Trait categories
• Tissues of the tooth
• Dental terminology
• Anatomy of tooth structure

3. Primary and Permanent Dentition

4. Dentition
Refers to all of the teeth in the maxillae and
the mandible
* maxillary arch - maxillary teeth
* mandibular arch - mandibular teeth
Maxillary arch
Mandibular arch

5. Humans Have Two Dentitions
Throughout Life
1) Primary Dentition - during childhood
2) Permanent Dentition - during adulthood
Primary
Permanent

6. Primary Dentition
• There are 20 teeth in the primary dentition
• 10 maxillary - 10 mandibular
• This dentition is also termed the deciduous
dentition
Permanent 1st Molars

7. Primary Dentition
The dental formula for one side of the mouth is:
I 2 C 1 M 2 = 10 teeth on either side
2 1 2
11 212
11 212

8. Deciduous Teeth
Those teeth that “fall out” due to a natural
process of tooth succession

9. Permanent Dentition
Also called the succedaneous
dentition - that which
succeeds the primary dentition
There are 8 teeth in each
quadrant
I 2 C 1 PM 2 M 3 = 16 teeth
2 1 2 3 each side

10. Permanent Dentition
First signs of this dentition appear at age 6

11. Permanent Dentition
A A A P P P P P
Anterior Teeth - incisors and canines
Posterior teeth - premolars and molars

12. Tooth Identification Systems

13. Tooth Identification Systems
There are three main systems used in modern
dentistry for the numbering of teeth. They
are:
* Universal Numbering System
* Palmer Notation System
* International Numbering System

14. Universal Numbering System
1. Suggested by Parreidt in 1882
2. Adopted by the A.D.A. in 1975
3. Uses numbers 1 through 32

15. Universal Numbering System
1 for upper right third molar around to 16
upper left third molar
1 16

16. Dropping down same side to 17 lower left
third molar and around to 32
Universal Numbering System
1732

17. For deciduous dentition, letters
A through T are used
Universal Numbering System
A B C D E F G H I J
T S R Q P O N M L K

18. Universal
Numbering
System

19. Palmer Notation System
Utilizes brackets to represent the four quadrants
Upper Right Upper Left
Lower Right Lower Left

20. • Permanent teeth are labeled 1 to 8 on each
side of the midline
• On deciduous teeth same brackets with
letters A through E
Palmer Notation System

21. Palmer System

22. International Numbering System
• Uses two digits for each tooth
• First digit represents dentition, arch and
side
• Second number denotes the tooth (1-4
perm. and 5-8 prim.)

23. International Numbering System
1 = permanent dentition, maxillary, right
2 = permanent dentition, maxillary, left
3 = permanent dentition, mandibular, left
4 = permanent dentition, mandibular, right
5 = primary dentition, maxillary, right
6 = primary dentition, maxillary, left
7 = primary dentition, mandibular, left
8 = primary dentition, mandibular, right

24. International Numbering System

25. Trait Categories

26. Trait Categories
Set Traits: (dentition traits) distinguish teeth
in the primary from secondary dentition

27. Trait Categories
Arch Traits:
distinguish maxillary
from mandibular

28. Trait
Categories
Class Traits: Distinguish the four categories
of teeth ... incisors, canines, premolars,
molars

29. Trait Categories
Type Traits: Distinguish teeth within one class

30. Tissues of the Tooth

31. Tissues Of A Tooth
1) Dentin
2) Enamel
3) Cementum
4) Pulp

32. Enamel
• Makes up the protective outer
surface of the anatomic crown
• Mostly inorganic and calcified
hard, white shiny surface of the
anatomic crown

33. Dentin
• Found in the crown and root, making up
bulk of tooth
• Found beneath the enamel and cementum
and surrounding the pulp tissue
• Not normally visible
• Mostly inorganic and calcified

34. Cementum
• Makes up the surface of the anatomic root
• Very thin next to cervical line
• Mostly inorganic calcified
• Dull yellow in color

35. Pulp
• Is non calcified found within the
pulp chamber
• Develops from the dental papilla
(from mesoderm)
• Surrounded by dentin except at the
apical foramen

36. Pulp
• Normally not visible except on
dental radiographs
• In the coronal portion termed
the pulp chamber
• In the root portion termed the
pulp canal(s)

37. Pulp - Functions
• Formative - dentin producing cells
(odontoblasts) produce dentin thoughout the
life of a tooth
• Sensory - nerve endings permit the sense of
pain

38. Pulp - Functions
• Nutritive - nutrient transport from the blood
stream to extensions of the pulp that reach
into dentin
• Defensive/Protective - responds to injury
and decay by forming reparative dentin

39. Junctions Of Tooth Structure
Cementoenamel Junction - also
called the cervical line,
separates the anatomic crown
from the anatomic root.

40. Junctions Of Tooth Structure
Dentinoenamel Junction - is the inner surface
of the enamel cap visible in cross section or
in badly worn teeth

41. Junctions Of Tooth Structure
Cementodentinal Junction - a.k.a.
dentinocemental junction is the inner
surface of cementum lining the root visible
in cross section or badly worn teeth

42. Anatomic Versus
Clinical Crown
Anatomic Crown - that part of the tooth
covered in enamel
Clinical Crown - that part of the tooth that is
visible in the oral cavity

43. Dental Terminology

44. Terminology Used To Distinguish
Tooth Surfaces
Facial Surface - the surface next
to the face, the outer surface
of a tooth resting next to the
cheeks or gums. Used in both
anterior and posterior teeth

45. Terminology Used To Distinguish
Tooth Surfaces
Buccal Surface - the facial
surface of posterior teeth.
Meaning next to the cheek

46. Terminology Used To Distinguish
Tooth Surfaces
Labial Surface - the
facial surface next to
the lips, generally
used for anterior
teeth

47. Terminology Used
To Distinguish
Tooth Surfaces
Proximal Surface - the surface or side of a
tooth that is next to an adjacent tooth, not
considered self-cleansing

48. Mesial Surface - is the surface of the tooth
nearest to the midline of the dental arch
Terminology Used
To Distinguish
Tooth Surfaces

49. Distal Surface - is the surface of the tooth
farthest from the midline of the dental arch
Terminology Used
To Distinguish
Tooth Surfaces

50. Terminology Used To Distinguish
Tooth Surfaces
Lingual Surface - is the
surface of maxillary and
mandibular teeth nearest
the tongue

51. Terminology Used To Distinguish
Tooth Surfaces
Palatal Surface –
is the surface of
maxillary teeth
nearest the palate

52. Terminology Used To Distinguish
Tooth Surfaces
Occlusal Surface - is the
chewing surface of the
posterior teeth found
within cusp and
marginal ridges

53. Terminology Used To Distinguish
Tooth Surfaces
Incisal Edge - is the cutting
edge, ridge or surface of
anterior teeth

54. Anatomy of Tooth Structure

55. Divisions Of The Crown And Root
Of A Tooth
Divisions Cervico-occlusally
Cervical 3rd
Middle3rd
Incisal 3rd
Cervical 3rd
Middle3rd
Occlusal 3rd
Anterior Posterior

56. Divisions Of The Crown
Of A Tooth
Divisions Mesiodistally
Distal 3rd
Middle3rd
Mesial 3rd

57. Divsions Of The Crown
Of A Tooth
Divisions Faciolingually
Lingual 3rd
Middle3rd
Facial 3rd

58. Divisions Of The Crown And Root
Of A Tooth
Divisions Cervico-occlusally
Apical 3rd
Middle3rd
Cervical 3rd
Cervical 3rd
Middle3rd
Incisal 3rd
Apical 3rd
Middle3rd
Cervical 3rd
Cervical 3rd
Middle3rd
Occlusal 3rd
Anterior Posterior

59. Morphology Of An
Anatomic Crown
Cusp - is a point, or
peak on the chewing
surface of premolar or
molar tooth

60. Morphology Of An
Anatomic Crown
Cusp Slopes Or Ridges - are the
inclined surfaces that form an
angle at the cusp tip

61. How Many Cusp Ridges
Does This Tooth Possess?

62. Morphology Of An
Anatomic Crown
Cingulum - is the
enlargement or bulge
on the cervical third of
the lingual surface of
the crown of anterior
teeth

63. Morphology Of An
Anatomic Crown
Labial Ridge- isaridgerunning cervico-incisally in approximately thecenter of
thelabial surfaceof thecanines

64. Morphology Of An
Anatomic Crown
Buccal Ridge - is the ridge running cervico-
occlusally in approximately the center of
the buccal surface of premolars

65. Morphology Of An
Anatomic Crown
Cervical Ridge - ridge
running mesiodistally on
the cervical one-third of
the buccal surface of the
crown, found on all
deciduous teeth but only
on the permanent molars

66. Morphology Of An
Anatomic Crown
Marginal Ridge - on incisor
and canine located on the
mesial and distal border of
the lingual surface

67. Morphology Of An
Anatomic Crown
Marginal Ridge - on
posterior teeth
located on the
mesial and distal
border of the
occlusal surface

68. Morphology Of An
Anatomic Crown
Triangular Ridge - on the occlusal surface of
posterior teeth, is the ridge from any cusp tip
to center of the occlusal surface - ML cusp
of upper molars have two

69. Morphology Of An
Anatomic Crown
Oblique Ridge - found
only on maxillary
molars made of the
triangular ridges of
the mesiolingual and
distobuccal cusps

70. Transverse Ridge - ridge crossing the occlusal
surface of posterior teeth in a B-L direction
and made of connecting triangular ridges
Morphology Of An
Anatomic Crown

71. Morphology Of An
Anatomic Crown
Mamelon - is one of
three tubercules
sometimes present on
the incisal edge of an
incisor tooth that has
not been subject to
wear

72. Morphology Of An
Anatomic Crown
Sulcus - is a broad
depression or valley
on the occlusal
surface of posterior
teeth

73. Morphology Of An
Anatomic Crown
Developmental Groove - is a
sharply defined, narrow and
linear depression, formed
during tooth development
separating lobes or a major
portion of a tooth - a fissure
may be found at the depth
of a developmental groove

74. Morphology Of An
Anatomic Crown
Supplemental Groove -
small irregularly placed
grooves not at the
junction of lobes or
major portions of the
teeth

75. Morphology Of An
Anatomic Crown
Fossa - a depression or hollow found
on the lingual surfaces of some
anterior teeth and on the occlusal
surfaces of posterior teeth

76. Morphology Of An
Anatomic Crown
Pits - often occur at the depths
of fossa where two or more
grooves join

77. Morphology Of An
Anatomic Crown
Furcation - is the place on
multirooted teeth where the
root trunk or base divides
into separate roots
Root
Trunk

78. Curve Of Spee
Anteroposterior curve of the occlusal plane -
curve of the maxillary arch is convex

79. Curve Of Wilson
Gradual curve of posterior teeth from left to
right side viewed from the anterior region -
curve of maxillary teeth is convex