rest and rest seat - minia.edu.eg · rest seat the prepared recess in a tooth or restoration...
TRANSCRIPT
REST AND REST SEAT
Dr. Shaima’a Ahmed Radwan
Vertical forces acting in gingival direction tending to move the denture towards the tissues
• DEFINITION: Rests are Rigid Extensions of a Partial Denture, Placed in Rest Seats, Which are Prepared on Either the Occlusal, Lingual Surfaces or Incisal Edges of the Teeth, Providing Support to the Partial Denture
auxiliary rest
(principle rest)
part of a clasp assembly
Rest seat The Prepared Recess in a Tooth or Restoration Created to Receive Occlusal, Incisal, or Lingual Rest
I. Occlusal Rest II- Lingual Rests III. Incisal Rest
RESTS
IV- Embrasure Hooks
I. Occlusal Rest
1.Conventional forms • 1- Should Be Rounded Triangular in Shape
• The Marginal Ridge Is Lowered Approximately 1 to 1.5 Mm of Teeth in Relation to a Vertical Line (permit sufficient bulk )
• Spoon Shaped Inclined Apically As It Approaches the Center of the Tooth
The floor of the rest seat should be spoon shaped(saucer)
-Rests , should be prepared in Sound Enamel
Rests , could be prepared in cast restorations, Crowns Or inlays
• Amalgam Restoration??????????????????????????
• It must not raise the vertical dimension of occlusion
2.Other forms
a. Boxed shaped occlusal rest
These rest seats should be restricted to tooth-supported dentures where the periodontal health of the abutment teeth is good. Helps in Preventing Lateral Movement of the Denture may result in the rest applying damaging horizontal loads on the abutment tooth.
B-Tipped molar(mesially inclined mandibular molar)
Extending the occlusal rest over the center of the mesiodistal fissure, directs the forces along the long axis of the tooth
B-Tipped molar(mesially inclined mandibular molar)
Additional occlusal rest Extended occlusal rest
C. ONLAY REST
Improve vertical dimension of occlusion splinting
D.Interproximal occlusal rest
E.Embrasure Rest
Rest seat distribution
Rest seat distribution
Gum striping in partial denture
II- Lingual Rests I- Occlusal Rest
III. Incisal Rest
Rests
IV- Embrasure Hooks
A- Cingulum Rest (inverted V Rest)
b. Canine Ledge
A Step-like Preparation 1.5 mm Deep
C. Ball Rest
1.5 Mm Deep - 2.5 Mm Wide
II- Lingual Rests
II- Lingual Rests I- Occlusal Rest
III. Incisal Rest
Rests
IV- Embrasure Hooks
III- Incisal Rest
Used Predominantly As Auxiliary Rests or As Indirect Retainers
-Applicable on Mandibular Teeth 2.5 Mm Wide and 1.5 mm Deep
LINGUAL VS INCISAL
The Lingual Placed Closer to the Center of Rotation of the Abutment Tooth
More Esthetic
Tongue
I. Occlusal Rest II- Lingual Rests III. Incisal Rest
RESTS
IV- Embrasure Hooks
IV- Embrasure Hooks
Placed in Embrasures Between Teeth Extending Over the B or Lab Surface but Never Extend Below S. L.