Tooth Morphology Basics

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
21 2
112
12
112
12

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
AA
A
P
PPP
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
Middle 3rd
Incisal 3rd
Cervical 3rd
Middle 3rd
Occlusal 3rd
Anterior Posterior

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

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

58. Divisions Of The Crown And Root
Of A Tooth
Divisions Cervico-occlusally
Apical 3rd
Middle 3rd
Cervical 3rd
Cervical 3rd
Middle 3rd
Incisal 3rd
Apical 3rd
Middle 3rd
Cervical 3rd
Cervical 3rd
Middle 3rd
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 - is a ridge running cervico-incisally in approximately the center of
the labial surface of the canines

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