2. Contents
Surfaces of teeth. 1
Line angles and point angles. 2
Depressions and Elevations on teeth. 3
Division in thirds. 4
Objectives
The prime objective of this lecture is to introduce the
dental terminology and its application
3. Learning nomenclature is the first and very important
step in understanding dental anatomy.
Crown is covered with enamel and root is covered with
cementum. The crown and root join at the cemento-
enamel junction (CEJ) which is also called the cervical
line. The junction of cementum and dentine is called
cemento-dentinal junction. The junction of dentine and
enamel is called dentinoenamel junction (DEJ).
To study and facilitate communication various surfaces
of teeth are recognized and given names.
4. Surfaces of teeth
.Crowns of all teeth have five surfaces
Facial Surface. 1
.Facial surface can be labial surface or buccal surface
a. Labial surface. The surfaces of incisors and canines that
.are towards the lip
b. Buccal surface. The surfaces of premolars and molars
.that face the cheek
6. Proximal Surfaces. 3
a. Mesial Surface
.All surfaces towards the midline
b. Distal Surface
All surfaces away from the midline. Mesial surface and
.Distal surface are collectively called proximal surface
Proximal surfaces
7. Incisal or Occlusal surface. 4
a. Incisal surface. The surface of incisors and canines that
come in contact with those in the opposite jaws during
the act of closure are called incisal surfaces
b. Occlusal surface. The surface of premolars and molars
that come in contact with those in the opposite jaws
.during the act of closure are called occlusal surfaces
12. Line and Point angles
When two of these surfaces meet, a line
angle is formed and when three surfaces
meet a point angle is formed
Line angle
Point angle
13. Line angles of anterior teeth
1. Mesio labial
2. Disto labial
3. Mesiolingual
4. Distolingual
Labioincisal. 5
Linguoincisal. 6
17. Point angles of anterior teeth
1. Mesiolabioincisal
2. Distolabioincisal
3. Mesiolinguoincisal
4. Distolinguoincisal
Point angles of Anterior teeth
18. Point angles of posterior teeth
1. Mesiobucco-occlusal
2. Distobucco-occlusal
3. Mesiolinguo-occlusal
4. Distolinguo-occlusal
Point angles of Posterior teeth
19. Depressions on tooth surface
Pit. A sharp pinpoint depression on the surface of the. 1
enamel
Fossa. An irregular depression or concavity on the. 2
.surface of a tooth
2 Pit. 1
1
Fossa. 2
20. .Sulcus. A long depression on the surface of a tooth. 3
4. Groove is a shallow linear depression on the surface
of a tooth.
A developmental groove is a shallow groove or line
between the primary parts of the crown or root.
A supplemental groove is less distinct and does not
mark the junction of primary parts.
22. Elevations on tooth surface
.Cusp. An elevation or mound on the crown of a tooth. 1
C C
C
C
C C
Cusps
23. 2. Cingulum is the lingual lobe of an anterior tooth and
makes up the bulk of the cervical third of the lingual surface.
C
Cingulum
24. 3. Lobe is one of the primary sections of formation in the
development of the crown. Cusps and mamelons are
representative of lobes.
4. Mamelons are three rounded protuberances found on the
incisal ridges of newly erupted incisor teeth.
25. Ridge. A linear elevation on the surface of a tooth
Marginal ridges are rounded borders of enamel that form
the mesial and distal margins of the occlusal surfaces of
posterior teeth and the mesial and distal margins of the
lingual surfaces of anterior teeth.
Triangular ridge is a ridge that descends from the tips of the
cusps of molars and premolars towards the centre part of
the occlusal surface.
Transverse ridge is formed by the union of buccal and
.lingual triangular ridges
Oblique ridge is a ridge obliquely crossing the occlusal
surfaces of maxillary molars.
Dr.Syed Sadatullah Ibnsina
National Medical College
29. Other important terms
Mid line. An imaginary line dividing the upper and lower
.arches into two equal halves
Anterior. Pertaining to or towards the front plane of the
.body
Posterior. Pertaining to or towards the back plane of the
.body
.Superior. Situated above another or towards the head
.Inferior. Situated beneath another or towards the feet
31. Division in thirds
To make study and communication easier the crown and
.root are divided into three halves
)Division in thirds occluso-gingivally (Crown cervical
Cervical third. 1
Middle
Middle third. 2
Incisal/Occlusal third. 3 incisal
Occlusal
Middle
cervical
32. )Division in thirds facio-lingually (Crown
Crown when viewed from front
Mesial third. 1
Middle third. 2
Distal third. 3
Distal Mesial
Middle
