This document defines and describes key concepts in occlusion, including: - Static occlusion refers to tooth alignment and articulation, while dynamic occlusion includes jaw function. - Ideal occlusion includes theoretical principles that an occlusion should have, while physiologic occlusion allows for individual variation. - Tooth contacts include centric contacts during jaw closure and eccentric contacts during jaw movements. - Imaginary curves like the Curve of Spee and Curve of Wilson describe ideal occlusion relationships. - Centric relation is the most superior jaw position while centric occlusion is maximal tooth intercuspation. - Disclusion describes how teeth separate during jaw movements due to condylar and incisal guidance.

2. Dr. ARAVIND H
Senior Lecturer
DEPARTMENT OF ORTHODONTICS AND
DENTOFACIAL ORTHOPEDICS
BASIC CONCEPTS
OF OCCLUSION

3. INTRODUCTION
The term occlusion has both STATIC and DYNAMIC aspects:
STATIC: Form, alignment and articulation of teeth within and
between the arches, and relationship of teeth to their supporting
structures.
DYNAMIC: Function of the stomatognathic system as a whole,
comprising of teeth, supporting structures, TMJ, neuromuscular and
nutritive systems.

4. SOME TERMINOLOGIES
IDEAL OCCLUSION: It is a preconceived theoretical concept of occlusal structures and functional
relationships that include idealized principles and characteristics that an occlusion should have.
PHYSIOLOGIC OCCLUSION: deviates from ideal and yet remains well adapted to that particular
environment.
BALANCED OCCLUSION: balanced and equal contacts are maintained throughout the entire arch
during all excursions of mandible.
FUNCTIONAL OCCLUSION: that which provides the highest efficiency during all excursive
movements
TRAUMATIC OCCLUSION: Abnormal occlusion that is capable of producing injury to the
periodontium

5. TYPES OF CUSPS
CENTRIC HOLDING CUSPS:
• Buccal cusps of mandibular posterior teeth
• Palatal cusp of maxillary posterior teeth
• Occlude into the central fossae and marginal ridges of opposing
teeth
• Also known as stamp cusps
NON SUPPORTING CUSPS:
• The maxillary buccal and mandibular lingual cusps
• Contact and guide mandible during lateral excursions and
mastication

6. ARRANGEMENT OF TEETH IN HUMANS
Human dentition exhibit two type of tooth arrangement while in
occlusion. They are:
CUSP- FOSSA OCCLUSION
• Stamp cusp of one tooth occludes with a single fossa of an
opponent
• Upper stamp cusps fit into all except the mesial fossa of the lower
teeth
• Lower stamp cusps fit into all upper fossa except the distal ones of
bicuspids
CUSP EMBRASURE OCCLUSION
In this type 0f arrangement, each tooth occlude with two opposing
teeth

7. IMAGINARY CURVES
CURVE OF SPEE
• It relates to the anteroposterior curvature of the occlusal surface, beginning at
the tip of the lower cuspid & following the cusp tip" of the bicuspids & molars
continuing as an arc through the condyle.
• The curve, when extended, forms a circle of about 4inch in diameter
CURVE OF WILSON
It is a mediolateral curve that contacts the buccal & lingual cusp tips of the
mandibular buccal teeth. It result, from inward inclination of the lower posterior
tooth.
CURVE OF MONSON
Obtained by extending the curve of Spee and Wilson to all the cusps and incisal
edges.

8. A. B.

9. CENTRIC RELATION & CENTRIC OCCLUSION
• CENTRIC RELATION is the relation of the mandible to the maxilla
when en the mandibular condyle are in the most superior and
retruded position in the glenoid fossa with the articular disc
properly interposed.
• Centric relation is also called ligamentous position Or terminal hinge
position. At centric relation, both the condyles are simultaneously
seated most superiorly in the glenoid fossa.
• CENTRIC OCCLUSION is that position of the condyle when the teeth
are in maximal intercuspation.
• Research show that centric occlusion is found to be 1-2mm ahead
of centric relation in majority of the population.

10. CENTRIC CONTA CTS
• They are areas of teeth that contact the opposing teeth. Classified
as:
POSTERIOR CENTRIC CONTACTS
• Consists of facial and lingual ranges of contacts.
• In Facial range of posterior contacts, mandibular facial cusp tips
contact central fossa and mesial marginal ridge of opposing teeth.
• Lingual range involves maxillary lingual cusp tips contacting central
fossa and distal marginal ridges of opposing mandibular teeth.
ANTERIOR CENTRIC CONTACTS
• They are in line with the facial range of posterior centric contacts.

11. ECCENTRIC OCCLUSION
Refers to the contact of teeth that occurs during movement of
mandible. Classified into two types:
FUNCTIONAL OCCLUSION
• Tooth contacts occur in the segment of the arch toward which the
mandible moves. Further divided into two types:
• 1) LATERAL FUNCTIONAL OCCLUSION: tooth contacts that occur on
canines and posteriors on the side toward which mandible moves.
• A) Canine guided
• B) Grouped lateral
• 2) PROTRUSIVE FUNCTIONAL OCCLUSION
NON FUNCTIONAL OCCLUSION
Tooth contacts that occur in the segment away from which the
mandible moves.

12. DISCLUSION
• It is used to describe dis-occlusion or seperation of non functional posterior
teeth during eccentric movements.
• Brought about by condylar and incisal guidance
CONDYLAR GUIDANCE
• IN case of protrusive movements, both condyles translates downwards along
the slope of articular eminence leading to disocclusion of posteriors.
• In case of lateral movements, condyle on the working side rotates on its axis
while condyle on the non working side translates forward, leading to
disocclusion of non working side.
INCISAL GUIDANCE
• Leads to mandibular incisors sliding down from the area of centric contacts
towards the incisal edges of maxillary anteriors, thus leading to posterior
disocclusion.

13. ANDREWS SIX KEYS TO NORMAL OCCLUSION
Andrew, during the 1970s put forward six keys to normal occlusion
after studying 120 patient models.
• MOLAR INTERARCH RELATIONSHIP
• MESIOLINGUAL CROWN ANGULATION
• LABIOLINGUAL CROWN INCLINATION
• ABSENCE OF ROTATION
• TIGHT CONTACTS
• CURVE OF SPEE

14. CONCLUSION
• By understanding various concepts of occlusion, we will be able to
formulate an ideal treatment plan for an individual that could bring
forward a final outcome where there is not derangement of jaw
movement, better cuspal and incisal relationship and improved
esthetics.