INDIAN DENTAL ACADEMY
Leader in continuing dental education
Alignment and occlusion of the dentition
-Factors and forces that determine tooth
-Intra-arch tooth alignment
-Inter-arch tooth alignment
-Occlusal contacts during mandibular
According to Glossary of Prosthodontic Terms:
“Occlusion is the act or process of closure or of
being closed or shut off”
Ramfjord and Ash: Occlusion = Contacts
“Multifactorial functional relationship between
the teeth and other components of the
masticatory system as well as with other areas
of the head and neck that directly or indirectly
relate to function, parafunction or dysfunction of
the masticatory system.”www.indiandentalacademy.com
Development of concept of occlusion--
1. Fictional period (prior to 1900)
2. Hypothetical period (1900-1930)
3. Factual period (1930 to present)
Fuller, Clark and Imrie-Antagonism,meeting
or gliding of teeth.
Talbot’s-(1903)Irregularities of teeth and their
Edward H. Angle(1899)- “Old Glory” and “Key
Matthew Cryer and Calvin Case-Occlusion
referred to the closure of the teeth one upon
Bennett (1908)-Functional analysis or
dynamic approach to occlusion.
Turner(1903)-Concept of physiologic rest.
Lister and Simon(1922)-Related teeth to the
rest of the face and cranium.
Milo Hellman-Racial variations in normal
Difference between static and dynamic
concepts of occlusion.
Broadbent and Planer-(1930)
Occlusion=Interdigitation of teeth + Status of
controlling musculature and functional factors.www.indiandentalacademy.com
Alignment and occlusion of the dentition:
Tooth positions are determined by various
controlling factors such as:
1. Factors and forces that determine tooth
2. Intra-arch tooth alignment.
3. Inter-arch tooth alignment.
1.Factors and forces that determine tooth
Labial to teeth are lips,cheeks-lingually directed
Tongue-labially and bucally directed forces.
Oral habits-biting on
Proximal contact wear-
mesial drift( because of
functional response of
alveolar bone and gingival
Abnormal muscular pattern-
Tongue thrust and visceral swallow.
2.Intra-arch tooth alignment:
-Relationship of the teeth to each other
within dental arch.
Plane of occlusion is not flat.www.indiandentalacademy.com
The curvature of the occlusal plane is due
to the varying degrees of inclination of
teeth in the dental arches.
3.Inter-arch tooth alignment:
-Relationship of the teeth in one arch to
those in the other.
Maxilla – 128 mm
Mandible – 126 mm
Arch width: Distance across arch.
The buccal cusp of mandibular posterior
teeth and lingual cusp of maxillary posterior
teeth occlude with the opposing central fossa
areas – Supporting cusps.
The centric cusp are broad and rounded.
The The buccal cusp of maxillary posterior
teeth and lingual cusp of mandibular
posterior teeth– Guiding or non-centric cusps
(sharp, with definite tips)www.indiandentalacademy.com
Functional outer aspect:
Present only on outer aspect of centric cusp.
This area assists in shearing of food therefore
non-centric cusps- shearing cusps.
provide stability to the
mandible in maximum
MESIO-DISTAL OCCLUSAL CONTACT
These cusp typically contacts
1. Central fossa areas: The actual contact point
are called centric stops, holding contacts, as
they serve to hold the teeth in a stable
2.Marginal ridge and embrasure areas:
Marginal ridge is slightly convex areas,
therefore the type of contact is cusp tip
contacting a flat surface.
COMMON OCCLUSAL RELATIONSHIPS OF
COMMON OCCLUSAL RELATIONSHIPS OF
Maxillary anterior teeth-labial to mandibular
Inclined labially (12º-28º).
Normally incisal edges of lower incisors
contacts lingual surfaces of upper incisors in
the lingual fossae which is 4mm gingival to
In normal occlusion, contacts on the anterior
teeth in the intercuspal position are much
lighter than on the posterior teeth.
Purpose of the anterior teeth-guide the
mandible through various movements.
Anterior guidance- It is the anterior tooth
contact that provide guidance to the mandible.
-determined by exact position and
relationship of the anterior teeth which can be
examined both horizontally and vertically.
the labial incisal edge of
maxillary incisor and labial
surface of mandibular
between the incisal
edges of the
OCCLUSAL CONTACTS DURING
The TMJ’s and the associated muscles allows
the mandible to move in all three planes-
(Sagittal,Frontal and horizontal) which
ultimately influences contact patterns on the
occlusal surfaces of the posterior teeth.
Eccentric- any movement of the mandible
from the intercuspal position that results in
Three types:Protrusive, Laterotrusive,