Occlusal Rest

Rest
Any unit of a partial denture that rest on a
tooth surface (occlusal, lingual or Incisal ) to
provide vertical support
Rest Seat
Portion of a tooth prepared to receive a rest

Occlusal rest
Cingulum Rests &
Incisal Rests
Occlusal onlays
Embrasure Hooks

Definition
Types
Requirements
Functions
Effect of occlusal
rests on the tooth

Occlusal Rest
A rigid extension of a partial denture that
contacts the occlusal surface of a tooth or
restoration

1. 1.It must fit the tooth accurately with
beveled margin????? To prevent food
stagnation
2. It must be at right angle or less to the
long axis of the tooth?????? To prevent
force tooth away from the saddle
3. It may rest in:
a) Natural depression on the occlusal surface
b) Shallow depression prepared in the enamel
c) In an inlay it is called( in-set occlusal rest)

4. The Thickness of the rest depends on:
a) The Alloy used
b) The Heaviness of the bite
c) Whether the rest is opposed by natural or
artificial teeth
5. It should cover 2/3 of the width of the
marginal ridge
6. The internal angle of the rest should be
rounded ????? To allow a considerable
thickness of metal so increase its strength

Support of the saddle
prevents denture base from moving
cervically & impinging gingiva
Transmission of lateral
load
Deflection of food
Improvement of
occlusion

Occlusal rest direct the vertical load with
long axis of the tooth
Torque will result when the occlusal rest is
placed on one side only of the occlusal surface
There are three solutions to prevent this torque:
1. Extending the rest over the center of the
mesio-destal fissure
2. Using 2 shorter rests, on mesial &distal surface
of the tooth
3. Placing the rest on the tooth away from the
saddle ??? To resist the rotatory movement

Cingulum
Rest
• Placed on palatal or lingual surfaces of
anterior teeth
• It is confined to upper anterior teeth
• Canines are usually favorable than centrals
• Placed in lower anterior teeth
Incisal Rest

It is an occlusal rest extending to
cover the whole occlusal surface of
the tooth
Onlays may be:
1. Gold
2. Chrome cobalt
3. Combination of metal & acrylic
resin is indicated when a large
interocclusal space is present

1) Partial denture Support
2) Correction of close bite
3) Improvement of occlusion
4) Reduction of cusp angle
5) Splinting

These are a form of rest which
placed in the embrasure between
two natural teeth
It is made in gold or chrome cobalt

1. Support
2. Resist lateral movements
3. Resist antro-posterior movements
4. Splint natural teeth
5. May act as indirect retainer

1. Separation of teeth by wedging
action
2. Appearance