It is the branch of dentistry that deals
with the normal functions of teeth and
all its related structures in the oral
PHYSIOLOGIC MORPHOLOGY of the
TEETH and the PERIODONTIUM
A. There is a definite form related
to purpose and function.
B. There are 3 major functions of
human teeth to which their form,
contour and alignment are directly
3. Phonetics (speech)
Periodontium- supporting tissues,
both hard and soft may suffer the
consequences of dentist-induced
imperfection of form.
COMPARATIVE DENTAL ANATOMY
A. Most primitive type of tooth
- conical in shape
-composed of a single cone or
-common in primitive vertebrates
-in modern times is exhibited by
lower vertebrates including rep-
-mainly homodonts with similarly
-hinge action of jaw, no lateral
movement for grasping prey and combat.
B. The dental systems of mammals have
evolved to much greater diversity.
-development of tritubercular form
of the tooth or 3 lobed (cusped tooth).
-mammals are heterodont in nature
bec.of different tooth form, displays
more than a single root per tooth.
-dogs are mammal that is fully
heterodont but lacks lateral jaw
movements due to interlocking cusps.
C. The most highly developed and complex
teeth, normally with 4 or more lobes
belongs to the PRIMATE (APES AND
- basically herbivorous diet of fruits.
- anthropod ape have dental
formulae identical to man however
these animals retained their
elongated canines hence, do not have
lateral jaw movement like in man.
D. Man has the most complex dental
mechanism of all animals.
-being omnivorous, homosapiens has
developed teeth to function both in
the mastication of meat and plant
foods.The elongated and interlocking
canines are reduced in size so that
they function with rest of the teeth
in lateral movements and the
individual teeth differ in both size
and development from other primates.
All teeth in human dentition are
comprised of four or more lobes.
-the ungulates (deer,cow,horse etc.)
displays a great range of jaw movement
being entirely herviborous, exhibit
relatively great latitude of jaw
CROWN SURFACE FORM
The geometric configuration of all
tooth crown surfaces (except incisal
and occlusal) can be placed in one of
three general categories: triangular,
trapezoidal or rhomboidal.
A. FACIAL and LINGUAL SURFACES
- Labial, buccal and lingual aspects,
all teeth are in the dental arches
can be roughly described as
-incisal or occlusal side forms the
base of the trapezoid.
- the cervical represents the
shorter parallel side to allow
adequate bony support around the
root of each tooth as well as
abundant circulatory capability.
Viewed from facial
Observe the pronounce
configuration with the
base at the incisal or
B. MESIAL and DISTAL SURFACES
a. Anterior Teeth
The crowns of anterior teeth as
viewed from their proximal surfaces,
exhibit a triangular shape, with the
base of triangle at the cervical and
the apex at the incisal. This shape
readily fits into the prescribed
function of the anterior teeth, since
the apex at the functions as a wedge
in tearing, biting and incising food
material, while the wider cervical
base provides strength for the crown
b. Maxillary Posterior Teeth
The crowns of maxillary posterior
teeth have proximal surfaces which
are roughly trapezoidal in shape, with
the base at the cervical and the
buccal and lingual sides constricting
toward the occlusal. This general
form aids in the distribution of
forces during mastication, as well as
serving as an aid to the tooth’s self-
+c. Mandibular Posterior Teeth
From the proximal aspect,
mandibular posterior teeth are
roughly rhom-boidal in their outline,
with the crowns inclined toward the
lingual. This form and inclination
allows for proper interlocking of the
mandibular and maxillary posteriors
VIEWED FROM PROXIMAL
A. Triangular with
the base at the
B. Trapezoidal with
the base at the
GENERAL CONSIDERATIONS IN
THE PHYSIOLOGY OF THE
A. TOOTH FORM and FUNCTION
-are directly related
-shapes of incisal/occlusal surfaces
of the teeth are related to their
-movements of the mandible
- when maxillary teeth comes in
contact with mandibular teeth
-used to designate the anatomic
alignment of the teeth and their
relationship to the rest of the
- any deviation in intermaxillary
and/or intermaxillary relations of the
teeth and/or jaw.
-teeth are arranged in arches in each
jaw and place in strong contact with
-line of forces must be parallel to
the long axis of the tooth.
- importance, to withstand forces.
-each tooth has contact areas except
3rd molars (distal)
-increase in size with age because of
1. due to abrading action of the teeth
against each other over a long
period of time.
2. brading action between proximal
-the actual mesio-distal length of
dental arches is continuously
becoming shorter moving towards
the midline or mesially.
-importance, stabilizes the teeth
in the dental arch and prevention
of food material from packing
between teeth resulting to
-there must be tight and proper
location of contact areas towards
1. Contact areas become more
cervically located from anterior to
posterior in each quadrant.
2. On individual teeth, the distal
contact area normally has a more
cervical location than the mesial
3. The relative size of the contact
areas increases from anterior to
posterior in each dental arch.
4. Anterior teeth have contact areas
which are, in general, centered in the
5. Posterior teeth have contact areas
which are, in general, located slightly
to the buccal center in the
representation of the
left quadrant of the
mandibular arch. Note
how the contact areas
asssume a more
gingival location as
they progress distally.
D. INTERPROXIMAL SPACES
-is the triangular shaped area between
adjacent teeth in the same arch
normally filled with interdental
-the triangle is formed by alveolar
bone at its cervical base, proximal
surfaces of the adjacent teeth on
each sides and contact area of the
adjacent teeth at its apex.
-importance, the triangular shape is
important in the health of the entire
periodontium by allowing its proper
stimulation and aids in the self-
cleansing process of the dentition.
-open space between the proximal
surfaces of 2 adjacent teeth in the
same arch where they diverge
facially, lingually and incisally
(occlusally) or cervically from the
-they are named according to location
depending from what aspect the
teeth are viewed.
-importance, serve as spillway for the
food material during mastication and
serve as integral part of the self-
cleansing process of the tooth.
Improper embrasure restoration will
result into overstimulation of the
1. From the facial or lingual aspect,
incisal (occlusal) embrasures
increase in relative size from the
anterior teeth toward the
2. From the facial or lingual aspect,
cervical (gingival) embrasures
decrease in relative size from
anterior to posterior.
3. From the incisal aspect, the labial
and lingual embrasures are nearly
equal in size in anterior teeth.
4. From the occlusal aspect, the lingual
embrasure is normally larger than
the buccal embrasure in posterior
5. When one side of an embrasure
(tooth outline) has a certain contour
(example-convex), the other side of
the embrasure will normally have a
F10- anterior teeth have
size on labial and
F11- as the arch
constrict and lingual
(cervical) and occlusal
F. CONTACT AREAS AND INCISAL
AND OCCLUSAL EMBRASURES
FRoM THE LABIAL AND BUCCAL
A. Central Incisors- contact areas
mesially on both central incisors are
located at the incisal third crowns.
B. Central and Lateral incisors- distal
outline of central incisor crown is
rounded, the lateral has a shorter
crown and has a more rounded
mesioincisal angle than central
C. Lateral and Canine- distal contact
area on the lateral incisor is at the
- mesial contact area on the
canine is at the junction of the incisal
and middle thirds.
- creates a more open
embrasure than between two central
and distal of central and mesial of
D. Canine and First Premolar
- canine has a long distal slope to
its cusp which puts the distal crest
of curvature at the center of the
middle third of the crown
- premolar, has a long cusp form
also, which puts its mesial contact
area rather high up on the crown.
-embrasure between these teeth
has a wide angle.
G. ROOT SHAPE, LENGTH,
-related to form and function
-canine has the longest and
strongest root for tearing
-molars are multirooted for grinding
1. Roots are widest at the cervical and
taper toward the apex.
2.Anterior teeth and premolars
normally have single roots. An
exception is the maxillary first
premolar which normally exhibits
the root branches, or buccal and a
3.Maxillary molars normally have 3
roots, one lingual and two buccal
4.Mandibular molars normally have 2
roots one mesial and one distal root.
ROOT SHAPE, LENGTH AND
a. Labial view of
shows single root.
b. Buccal view of
max.molar shows 2
roots (1 mesial and 1
c. Buccal view of
max.molar shows 3
H. FACIAL AND LINGUAL
HEIGHTS OF CONTOUR (CREST
-is the greatest area of contour on the
facial and lingual surfaces, and best
viewed from proximal.
-proximal surface also have heights of
contour which are normally located at
the contact areas.
-aid in proper protection and
stimulation of the gingival tissue.
-if the contour is excessive, the flow
of food material will be deflected
from the gingival and improper
stimulation of these tissues may
result in their breakdown.
-inadequate contour allows inadequate
protection, and the overstimulation
to the gingival tissues may also result
in their destruction.
1. The height of contour on both the
labial and lingual surfaces of all the
anterior teeth is located in the
2. The height of contour of the buccal
surfaces of all posterior teeth is
located in the cervical third.
3. The height of contour of the lingual
surfaces of posterior teeth is
located in the middle or occlusal
CREST OF CURVATURE
(PROXIMAL OF M1)
A. Correct contour.
C. M1 with less than
a. ant.tooth showing labial
and lingual crest of cur-
vature which are both in
the cervical third.
b. Mand.post tooth with
buccal crest of curva-
ture in the cervical 3rd
and the lingual height of
contour in the occlusal
c. Max.post.tooth with the
buccal crest of curvature
in cervical 3rd
crest of curvature in the
I. CERVICAL LINE CURVATURES
1. The amount (depth) of cervical line
curvature on any individual tooth is
normally greater on the mesial than
2. Cervical lines adjacent proximal
surfaces of adjacent teeth have
approximately the same depth of
3. The cervical line is normally curved
(convex) toward the apical on the
facial and lingual surfaces of teeth.
4. The cervical line is normally curved
(convex) toward the incisal (occlusal)
on the proximal surfaces of teeth.
5. The depth of the curvature on all
surfaces is greater on anterior teeth
and decreases toward the posterior.
The cervical line curvatures
as seen from mesial and
distal views on a C,PM and
M. Note the greater
incisal or occlusal cervical
line curvature on the
mesial surfaces. Note the
more distally located the
tooth is in the arch, the
less pronounced the
cervical line curvature.
The cervical line
curvatures as seen
from the buccal
(labial) and lingual.
CERVICAL LINE OR CEJ- a line around
the tooth where enamel and
cementum meet. This is stable.
MARGIN/GINGIVAL CREST- line
which marks the level of termination
of the soft tissue surrounding the
tooth. The gingival level is variable
and usually above the cervical line
early in life, often receding to a lo-
wer level as the individual becomes
ANATOMICAL CROWN- portion of
tooth covered by enamel.
CLINICAL CROWN- portion of tooth
which is visible in the mouth.
ANATOMICAL ROOT- portion of the
tooth covered by cementum.
CLINICAL ROOT- portion of the tooth
not visible in the mouth.
J. AXIAL POSITION- inclination of a
tooth from a vertical axis.
Importance- for proper occlusal
function of the dentition.
• roots- lingual inclination and
moderate distal inclination
• Faciolingual- great root inclination
• Mesiodistal- nearly straight with only
minor mesial root inclination
• Canine- slight distal root inclination
• Mesiodistal- distal root inclination
• Faciolingual- premolar 1 towards
• Premolar 2 towards buccal
• moderate to great buccal and distal
K. GENERAL OCCLUSAL CURVATURES
and AXIAL POSITION
1. Allow the most efficient use of
the forces of mastication.
2. Stabilizing and protecting the
CURVE OF SPEE- curve line begins at
the tip of the canines and follows the
buccal cusp tips of the premolar and
molars posteriorly viewed buccally.2
Curve of Spee
Lateral view of
trating the Curve
CURVE OF WILSON- the medio-
lateral curvature of the occlusal
plane of posterior teeth.
-2 dimensional but in opposite
direction to the curve of Spee.
- crowns of mandibular posterior
teeth inclines lingually while crowns
of maxillary posterior teeth inclines
- this curve becomes deeper
posteriorly, so that the molar’s
inclination is greater than that of the
Importance- to complement the paths
of the condyles of the mandible in its
CURVE OF WILSON
Curve of Wilson as seen
in a 1st
sectional view of the
maxilla and mandible.
Note that to conform
to this curve, the
lingual cusps of max.
molars and the buccal
cusps of mandibular
molars appear to be
CURVATURE (SPHERE OF
• 3 dimensional curvature of the
occlusal plane combination of curve
of Spee and Wilson.
• It is in the form of ball and sphere.
• Concave on mandibular arch/convex
SPHERE OF MONSOON
A Segment of a large
imposed on the