OCCLUSION IN

PROSTHODONTICSDr. Aeysha Siddika

FCPS (Trainee)Department of prosthodontics

Faculty of DentistryBSMMU

OCCLUSION

The static relationship between the incising or masticating

surfaces of the maxillary or mandibular teeth or tooth

analogues.

MUTUALLY PROTECTED OCCLUSIONAn occlusal scheme in which the posterior teeth

prevent excessive contact of the anterior teeth in maximum intercuspation, and the anterior teeth disengage the posterior teeth in all mandibular excursive movements.

CENTRIC POSITION PROTRUSIVE POSITION LATERAL POSITIONWorking Nonworking

Only posterior tooth make contact.

Anterior tooth have a space of minimum 30 microns.

Canine and posterior teeth disclude .

Mesial inclines of mandibular first premolar buccal cusps may contact.

Maxillary canine guide the mandible.

Posterior teeth disclude.

No tooth contacts.

MUTUALLY PROTECTED OCCLUSION

In lateral position, working side In protrusive position

ADVANTAGES OF MUTUALLY PROTECTED OCCLUSION

1) Minimum amount of tooth contact is involved and this makes for better penetration of the food.

2) The force is closer to the long axis of each tooth.

3) The arrangement of the marginal, transverse and oblique ridges so that they have a shearing action, which makes for a much more chewing apparatus.

GROUP FUNCTIONMultiple contact relations between the maxillary

and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces.

CENTRIC POSITION PROTRUSIVE POSITION LATERAL POSITION

Working Nonworking Posterior tooth make contact.

Anterior teeth may or may not contact.

Canine and posterior teeth disclude .

Teeth contact (mostly desirable canine, premolar, mesiobuccal cusp of 1st molar)

No tooth contacts.

GROUP FUNCTION

ADVANTAGES OF GROUP FUNCTION OCLUSION

1) Lateral pressure are distributed to all working side tooth.

2) Long centric, so allow some freedom of movement in an anteroposterior direction.

BALANCED OCCLUSION

The bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions.

CENTRIC POSITION PROTRUSIVE POSITION LATERAL POSITIONWorking Nonworking

Anterior and posterior teeth contact

All maxillary and mandibular teeth contact

Posterior teeth make contact

Posterior teeth make contact.

BALANCED OCLUSION

In lateral position, working side In lateral position, balancing side

ADVANTAGES OF BALANCED OCCLUSION

1) Help to seat the denture in a stable position during function.

2) Patients do not upset the normal static, stable, and retentive position of their dentures.

3) In balanced occlusion, the denture bases are stable during bruxing activity.

OCCLUSION IN NATURAL DENTITION

• Posterior disclusion on protrusion • Disclusion on non working side during lateral

movement.• Occlusion on working side (either canine

guided/group function) during lateral movement.

DESIRABLE OCCLUSION FOR COMPLETE DENTURE

1) Stability of occlusion in centric relation.2) Balanced for all eccentric contacts bilaterally

for all eccentric mandibular movements

The balancing arrangement in centric occlusion, buccal view.

In working occlusion, buccal view.

In balancing position, buccal view

3) Control of horizontal forces by buccoligual cusp height reduction according to the residual ridge resistance form and interarch distance.

4) Functional lever balance by favorable tooth to ridge crest position

5) Unlocking the cusp mesiodistally to allow for gradual but inevitable settling of the bases due to tissue deformation and bone resorption.

6) Cutting and shearing efficiency of the occlusal surface (sharp cusps or ridges).

7) Anterior clearance of teeth during mastication. Minimum occlusal contact between the upper and lower teeth to reduce pressure during function.

DESIRABLE OCCLUSION FOR RPD

**Simultaneous bilateral contacts of opposing posterior teeth must occur in centric occlusion.

1)Kennedy class-I-

>>> Mandibular RPD opposed by natural dentition.

Contact on working side

No contact on balancing side.

>>>Maxillary RPD opposing natural dentition or mandibular bilateral distal extension RPD

Simultaneous contact on working and non working side.

In lateral position, nonworking sideIn lateral position, working side

>>>Mandibular RPD opposed by maxillary complete denture-

During lateral movement, both working and balancing

side make contact.Not necessarily balanced in protrusion.

In lateral position, nonworking side

In lateral position, working side

In protrusive position

2)Kennedy class-II Contact on working side No contact on balancing side.

In lateral position, nonworking sideIn lateral position, working side

3) Kennedy class-III similar to occlusion in harmonious natural

dentition

4) Kennedy class-IV Contact in intercuspal position No contact in eccentric position

DESIRABLE OCCLUSION FOR FPD**Similar as occlusion in natural dentition Either mutually protected or group function

occlusion.

**In the following cases, desirable occlusion should be group function

-Periodontally compromised supporting anterior teeth.

-Missing canine -Angle class-II and class-III malocclusion -Crossbite

DESIRABLE OCCLUSION FOR OSSTEOINTEGRATED PROSTHESIS

1) Full-arch fixed prosthesis Bilateral balanced occlusion with opposing complete

denture Group function occlusion or mutually protected

occlusion with shallow anterior guidance when opposing natural dentition

Freedom in centric (1–1.5mm)

2) Overdenture Bilateral balanced occlusion using lingualized occlusion Monoplane occlusion on a severely resorbed ridge

3) Posterior fixed prosthesis Anterior guidance with natural dentition Group function occlusion with compromised canines Centered contacts, narrow occlusal tables, flat cusps Cross bite posterior occlusion when necessary

4) Single implant prosthesis Anterior or lateral guidance with natural dentition Light contact at heavy bite and no contact at light bite Centered contacts (1–1.5mm flat area) Increased proximal contact

References:

1) JUNHEI FUJIMOTO: CONTEMPORARY FIXED PROSTHODONTICS.2) HERBERT T. SHILINBURG, FUNDEMENTAL OF FIXED PROSTHODONTICS.3) SUMAIYA HOBO: OSSEOINTEGRATION AND OCCLUSAL REHABILITATION

4) SHELDON WINKLER: ESSENTIALS OF COMPLETE DENTURE PROSTHODONTICS.

5) DEEPAK NALLASWAMY VEERAIYAN: TEXTBOOK OF PROSTHODONTICS6) SOME INFORMATION FROM INTERNATE