Dental anatomy introduction for BDS first year students

Introduction andnomenclature of dental anatomy
Dr.Madhusudhan reddy

objectives
• Introduction of dental terminology and its
application
• Understanding dental anatomy
• To study and facilitate communication about
various aspect of teeth

introduction
• Midline: imaginary vertical
line which divides each arch
as well as body into approx
equal halves
• Maxillary teeth: teeth
arranged in upper arch
• Manduibular teeth: teeth
arranged in lower arch

Mandibular denture
Maxillary teethMaxillary denture
Mandibular teeth

• Quadrants: two approximately equal portions of
each arch divided by midline
• Four in entire mouth and termed as
1. maxillary (upper) right
2. maxillary (upper) left
3. mandibular (lower) right
4. mandibular (lower) left

• Occlusion: manner in which mandibular teeth
contact maxillary teeth
• Mastication: term for process of biting or chewing
of food

Important terminologies
• Midline: 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

Dentition
• In human two dentitions are present:
– 1. Deciduous (Primary)
– 2. Permanent (Secondary)
(mixed or transition dentition)

Deciduous teeth
• So named because they are shed like the leaves of
tree in autumn
• 20 total deciduous teeth
• Erupts from 6 months to 2 years
• other non scientific names for deciduous teeth
include “milk” teeth, “baby” teeth and
“temporary” teeth

Permanent dentition
• Teeth of the second, or adult dentition
• There are 32 permanent teeth
• Erupt from 6-21 years of age

Classification of teeth (Primary)

Classification of teeth (permanent)

Succedaneous teeth
• Simply means “succeeding” deciduous teeth
• Twenty deciduous teeth to be replaced, there must
be twenty succedaneous teeth
• Incisors and canines – replace their deciduous
counterpart

• Premolars – which replaces deciduous molars
• Molars are not considered as succedaneous teeth

Dental formulae
Primary dentition
Permanent dentition

Eruption patterns
• deciduous dentition

Tooth numbering system
• Tooth numbering or “short hand” system of tooth
notation.
• Necessary in clinical practice for
– Recording data
– Communication

• The various tooth notation systems :
1. Zsigmondy palmer notation system
2. Universal notation system
3. FDI system

Zsigmondy palmer notation system
• 1861 – Adolph Zsigmondy
• Primary teeth-
• Permanent teeth-

FDI system(federation dentaire internationale)
• Two digit system
• First digit indicates the quadrant and second digit
indicates the tooth within the quadrant
• 1 to 4 and 5 to 8 as the first digit indicates
permanent and primary dentition respectively
• 1 to 8 and 1 to 5 as the second digit indicates
permanent teeth respectively.

General oral and dental anatomy
• Anatomical crown: portion of tooth which is
covered by enamel
• Clinical crown: portion of tooth which is visible in
mouth
• Clinical crown may, or may not correspond to
anatomical crown, depending on level of soft tissue
and may also include a portion of anatomical root.

• Anatomical root: portion of tooth which is covered
with cementum
• Clinical root: portion of tooth which is not visible
in mouth
• Clinical root is an ever changing entity and may,
or may not correspond to anatomical root

• Enamel: hard, mineralized tissue which covers
dentin of anatomical crown of a tooth and hardest
living body tissue
• Dentin: hard tissue which forms main body of
tooth and surrounds pulp cavity and is covered by
enamel in anatomical crown and by cementum in
anatomical root.

• Cementum: a layer of hard, bone like tissue which
covers dentin of anatomical root of tooth
• Cervical line: identifiable line around external
surface of a tooth where enamel and cementum
meet and also called cemento-enamel junction or
CEJ
• Cervical line separates anatomical crown and
anatomical root .

• Dentino-enamel junction or DEJ: internal line of
meeting of dentin and enamel in anatomical crown
of a tooth
• Pulp: living soft tissue which occupies pulp cavity
of a vital tooth and contains tooth’s blood vessels
and nerve supply.

• Pulp cavity: entire internal cavity of tooth which
contains the pulp and consists of the following entities
– Pulp canal: portion of pulp cavity which is located in
root of the tooth (also called as root canal)
– Pulp chamber: enlarged portion of pulp cavity which
is found mostly in anatomical crown
– Pulp horn: usually pointed incisal or occlusal
elongations of pulp chamber which often correspond
to cusps, or lobes of teeth.

• Alveolar process: entire bony entity which
surrounds and supports all teeth in each jaw
member
• Alveolus: bony socket, or portion of alveolar
process, into which an individual tooth is set

• Periodontal ligament: fibrous attachment of tooth
cementum to the alveolar bone
• Gingiva: “gum” or “gums”, or fibrous tissue
enclosed by mucous membrane that covers
alveolar process and surrounds neck of teeth

Surfaces of teeth
• Crowns of all teeth have 5 surfaces
– Facial surface: facial surface can be labial surface
or buccal surface
– Labial surface: the surface of incisors and canines
that are towards lip
– Buccal surface: the surfaces of premolars and
molars that face cheek

• Lingual surface (palatal surface)
– Surface facing towards tongue

• Proximal surfaces
– Mesial: surfaces towards midline
– Distal: surfaces away from midline.

• Incisal or occlusal surface:
– 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
– Occlusal surface: the surface of premolars and
molars that come in contact with those in
opposite jaws during act of closure are called
occlusal surfaces.

Line angles and point angles
• When two surfaces of a tooth meet, a line angle is
formed
• And when three surfaces meet a point angle is
formed

Line angles of anterior teeth
1. Mesio-labial
2. Disto-labial
3. Mesio-lingual
4. Disto-lingual
5. Labio-incisal
6. Linguo-incisal

Line angles of posterior teeth
– Mesio-buccal
– Disto-buccal
– Mesio-lingual
– Disto-lingual
– Mesio-occlusal
– Disto-occlusal
– Bucco-occlusal
– Linguo-occlusal

Point angles of anterior teeth
– Mesio-labio-incisal
– Disto-labio-incisal
– Mesio-linguo-incisal
– Disto-linguo-incisal

Point angles of posterior teeth
– Mesio-bucco-occlusal
– Disto-bucco-occlusal
– Mesio-linguo-occlusal
– Disto-linguo-occlusal

Depression on toothsurface
1. Pit: A small pinpoint depression on the surface of
enamel
2. Fossa: An irregular depression or concavity on
surface of tooth

• 3. Sulcus: A long depression on
the surface of a tooth
• 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

Elevations on toothsurface
• 1: Cusp: an elevation or mound on the crown of a
tooth

• 2: Cingulum: is the lingual lobe of an anterior
tooth and makes up the bulk of the cervical third
of the lingual surfaces

• 3. Lobe: is one of the primary section of formation
in development of crown
• Cusps and mamelons are representative of lobes
• 4. Mamelons: are three rounded protuberances
found on incisal ridges of newly erupted incisor
teeth

• 5. Ridge: A linear elevation on the surface of a
tooth
– Marginal ridges: are rounded borders of
enamel that form mesial and distal margins of
occlusal surfaces of posterior teeth and mesial
and distal margin of lingual surface of anterior
teeth

– Triangular ridge: is a ridge that descends from
the tips of the cusps of molars and premolars
towards the center part of the occlusal surface
– Transverse ridge: is formed by the union of
buccal and lingual ridges

– Oblique ridge: is a ridge obliquely crossing the
occlusal surface of maxillary molars

– Cusp ridge:
• Each cusp has four cusp ridges extending in
different directions (mesial, distal, facial, lingual)
from its tip
• Normally the cusp ridge which extends towards
central portion of occlusal surface is also a
triangular ridge
• Named by the direction they extend from the
cusp tip

– Inclined planes:
• The sloping area found between two cusp
ridges
• Planes are named by combining names of
two cusp ridges between which they lie
• Each cusp exhibits four inclined planes

Thirds of tooth
• To make study and communication easier the crown
and root are divided into three halves
• Division in thirds occluso-gingivally (crown)
– Cervical third
– Middle third
– Incisal/occlusal third

Division in thirds mesio-distally
• Crown when viewed from front
– Mesial third
– Middle third
– Distal third

Division in thirds facio-lingually
• Crown when viewed from the side
– Facial third
– Middle third
– Lingual third

Thirds - root
• Cervical third
• Middle third
• Apical third

Dental anatomy introduction for BDS first year students

In this document