1. Harvard School of Dental Medicine Department of Restorative Dentistry
Predoctoral Curriculum in Dentistry
Diagnosis and Prevention Block 2002
Dental Terminology
Msd Fábio Tunes

2. Dental Terminology - Why ?

3. Maxillary and Mandibular Teeth
The portion of the jaw that
supports the teeth is called
the alveolar process. The
bony socket in which the
root fits is called the
alveolus.
Teeth in the upper jaw are
called maxillary teeth. In
the lower jaw they are
called mandibular teeth.

4. Tooth Eruption The crown portion of the tooth erupts through the bone
and alveolar ridge mucosa. The tooth continues to erupt
from the bone and surrounding oral mucosa, now
called gingiva.

5. Crown and Root Eruption of a tooth is thus moving of the tooth through
its surrounding tissues so that the clinical crown
gradually appears longer.

6. Crown and Root Each tooth has a crown and root
portion. The crown is covered with
enamel, the root is covered with
cementum. Crown and root are
joined at the cemento-enamel
junction, also called the CEJ. The
line that demarcates it is called the
cervical line.

7. Crown and Root The anatomical crown is the whole crown of the tooth
that is covered by enamel,
whether erupted or not. The
clinical crown is only that
part seen above the gingiva.
Therefore, if the anatomical
crown does not fully erupt, the
part that is visible is considered
the clinical crown, and the un-
erupted portion is part of the
clinical root.

9. Crown and Root
The root portion may be single or multi-rooted with a bifurca-
tion or trifurcation, i.e., division of the root portion into two
or three roots. Each root has one apex, or terminal end. The
root portion is held in its position relative to the other teeth in
the dental arch by being firmly anchored in the bony alveolar
process of each jaw.
Trifurcation
Alveolar
Process A A
Bifurcation

10. Dental Tissues
Enamel
Dentin
Cementum
Pulp

11. Enamel Most densely mineralized and hardest tissue in the human body.
96% unorganic and 4% organic matter and water.
Forms the outer surface of the anatomic crown.
Thickest over the tip of the crown,
becomes thinner as it approaches
the cervical line.
Color varies with thickness and mineralization.

12. Dentin
Dentin forms the main portion or body of the tooth (crown and root)
It is wrapped in an envelope of enamel that covers the crown, and an envelope of cementum that covers the root.

13. Dentin
Hard, dense, calcified tissue; softer than enamel but harder than bone or cementum.
Chemical composition is 70% inorganic and 30% organic matter and water.
Appears yellowish, has elasticity
Unlike enamel, dentin is capable of adding to itself (secondary dentin, reparative dentin); dentin-forming cells = odontoblasts

14. Dentin • Secondary Dentin: Is the dentin that continues to be laid
down in the pulp chamber after tooth
eruption
• Reparative Dentin:
Is the dentin laid down in response to
caries or trauma.

15. Cementum Bone-like substance that covers the root.
Main function is to provide a medium for attachment of the tooth to the alveolar bone as part of the periodontium
Not as dense or hard as enamel or dentin but is denser than bone to which it bears physiological resemblance.
The chemical composition is 45% to 50% inorganic and 50% to 55% organic components.

16. Cementum
The union of cementum and dentin is called the dentino-cemental junction.
2 types of cementum:
A) cellular - confined to the apical 1/3 of root and can reproduce itself.
acellular - covers the entire anatomical root.
Cementum as dentin continues to be formed after tooth eruption by cementoblasts

17. Pulp
The pulp is the nourishing, sensory, and dentin-reparative system of the tooth.
Composed of blood vessels, lymph vessels, connective tissues, nerve tissues, and dentin formation cells (odontoblasts)

18. Pulp
Pulp is housed in the center of the tooth within the dentin surrounding the pulp tissue.
The walls of the pulp cavity are lined with odontoblasts. Their chief function is to lay down primary and secondary dentin.

19. Pulp Anatomically the pulp chamber is divided into two areas:
1) The pulp chamber in the coronal portion of the tooth.
2) The root (pulp) canals in the roots of the tooth.
Pulp chamber and root (pulp) canals = pulp cavity.

20. Types of Teeth
Anterior Teeth:
Incisors
Canines
Posterior Teeth:
Premolars
Molars

21. Types of Teeth
Functions of teeth vary.
Tooth shapes and sizes differ with their location in the jaws.
The three basic functions of teeth are cutting, holding or grasping, and grinding.

22. Incisors Eight incisors total: 2 maxillary centrals (LI)
2 maxillary laterals (CL)
2 mandibular centrals (ci)
2 mandibular laterals (li)
Incisors are designed to cut
Cutting edge = incisal edge LI CI CI LI li ci ci li

23. Incisors The tongue side, or lingual surface, is shaped like a shovel:
• aids in guiding the food into
the mouth.
• is the major contributor to
the anterior guidance of
occIusion

24. Canines 4 canines total: 2 maxillary, 2 mandibular
Designed to function as holding or grasping teeth
Also used as a tearing tool
Longest teeth in the human dentition
Canine guidance in lateral excursive movements of occlusion C C C C

25. Canines
Canines are the best anchored and most stable teeth, since they have the longest roots.
Canines are shaped triangularly in cross section. This makes it possible for a canine to hold its place in the corner of the mouth.
This shape resists both anterior and posterior forces of displacement.

26. Premolars (or Bicuspids)
A cross between canines and molars.
8 premolars: 1st and 2nd in each tooth quadrant
Not as long as canines, and usually have two cusps, rather than one large ridge.
Like canines they aid in holding food, and they also help grind rather than incise it (the pointed buccal cusps hold the food while the lingual cusps grind it.)

27. Molars Larger than premolars
Most posterior teeth: 1st, 2nd and 3d molars
The function of the 12 molars is to chew or grind up food.
They do not have incisal edges, instead they have cusps, which are designed to interlock upper and lower molars.
There are 4 or 5 cusps on the occlusal surface of each molar.

28. Molars Maxillary (upper) and mandibular (lower) molars
differ greatly from each
other in shape, size, number
of cusps, and roots.

29. Surfaces of Teeth
Crowns of the teeth are divided into surfaces named according to the direction in which they face.
Anterior teeth have
4 surfaces (m, f, d, l) plus the incisal ridge or edge
Posterior teeth have
5 surfaces. The 5th surface is the occlusal surface

30. Surfaces of Teeth Surfaces facing the tongue = lingual surfaces.
Surfaces facing the cheeks = facial surfaces, or labial (lip) surface for anterior teeth, buccal (cheek) surface for posterior teeth

31. Surfaces of Teeth
A tooth surface facing that of a neighboring tooth in the same arch (next to each other) is called a proximal surface.
Each tooth has two proximal surfaces: mesial and distal. The mesial proximal surface of a tooth is closest to the midline of the face. The distal proximal surface faces away from the midline.

32. Division of Surfaces
For the purpose of facilitating the location of various areas within a specific surface of a tooth, the surface is divided into thirds - mesial, middle and distal third - of each the facial and lingual surface.

33. Division of Surfaces
The proximal (mesial and distal) surfaces of a tooth are divided into a facial, a middle, and a lingual third.
Surfaces are further divided into sections perpendicular to the above, i.e. any of the proximal, facial, or lingual surfaces are divided into an incisal, a middle, and a cervical third.
Posteriorly, the incisal 1/3
is called the occlusal 1/3.

34. Line Angles The line angle forms the junction
between two tooth surfaces; e.g.,
the junction of the buccal surface
and the occlusal (incisal) surface
of a tooth is a line angle.

35. Line Angles
Line Angles for Anterior Teeth

36. Line Angles
Line Angles for Posterior Teeth

37. Point Angles
A point angle is the point at which three surfaces meet; e.g. the point at which the mesial, labial and incisal surfaces join is called the mesio-labio-incisal point angle

38. Point Angles
Point Angles for Anterior Teeth

39. Point Angles
Point Angles for Posterior Teeth

40. Landmarks
The crown portion of teeth develops from 4 or more growth centers or lobes.
The lobes grow and eventually fuse leaving but a line or groove on the erupted tooth where fusion of the lobes took place.
These shallow grooves or lines that separate the original growth centers are called developmental grooves.

41. Landmarks
Incisors, canines and most premolars are developed from 4 lobes, 3 facial and 1 lingual.
1st molars are developed from 5 lobes: the upper from 2 facial and 3 lingual, the lower from 2 lingual and 3 facial lobes.
2nd molars are developed from 4 lobes, 2 facial and 2 lingual.

42. Landmarks
Anterior teeth show 2 develop-mental grooves on their labial surfaces. These 2 grooves separate the 3 lobes that formed the labial surface.
The fourth developmental lobe of anterior teeth is located at the lingual surface of the crown.
This fourth lobe is called the cingulum, and it makes up the bulk of the cervical third of the lingual surface of an anterior tooth.

43. Landmarks A concavity is a carved-out section or area -> Fossa
The opposite of a concavity
is a convexity, a bulging out area of the tooth crown
- > Ridge, Cusp
(no cusp on incisors!)

44. Landmarks
A fossa (plural fossae) is a depression or concavity, on an area of the tooth crown.
A tubercle is a small elevation of enamel on some portion of the crown of a tooth.
Fossae

45. Landmarks
Anterior teeth have a lingual fossa between the marginal ridges and incisal to the cingulum.
A pinpoint hole within the fossa, is called a pit.
Pits are named after their location on a tooth; e.g a lingual pit occurs on the lingual surface of a tooth. C

46. Landmarks
A cusp is a mound on the crown portion of the tooth that makes up a major division of its occlusal or incisal surface.
Cusps are found on premolars, molars and canines, not on incisors.
Cusp are name after their location (MB, DB, ML, DL)
Buccal
Mesio-Buccal
Disto-Buccal C C
Mesial
Distal C C
Disto-Lingual
Mesio-Lingual
Lingual

47. Landmarks
Marginal ridges are the rounded borders of enamel that form the mesial and distal shoulders of the occlusal surfaces of posterior teeth and the mesial and distal shoulders of the lingual surface of the anterior teeth.

48. Landmarks Triangular ridges (TR) are the main ridges
on each cusp that run
from the cusp tip to
the central part of the
occlusal surface, i.e.
the central, mesial,
distal grooves and
pits
MR = Marginal ridge TR TR MR MR TR TR

49. Landmarks
A transverse ridge is the union of a buccal and a lingual triangular ridge that cross the occlusal surface of a posterior tooth.