the rpi system

Category: Education

Presentation Description

rest, proximal plate, i bar


By: aisha.alisha (84 month(s) ago)


Presentation Transcript

The RPI System. : 

The RPI System. Dr. Abhiram.S BDS

Contents : 

Contents Introduction Direct retainers Clasps I bar removable partial denture RPI


INTRODUCTION RPI stands for: Rest. Plate (proximal). I bar clasp.


INTRODUCTION Modified I bar retainer system Krol 1973 Principle “stress control with minimal tooth and gingival coverage”

Direct retainers : 

Direct retainers Intracoronal retainers Extracoronal retainers Precision semi precision extra coronal attachment clasp It is that component part of a removable partial denture that is used to retain and prevent dislodgement, consisting of a clasp assembly or a precision attachment --GPT


CLASPS On basis of DESIGN Circumferential clasps Bar clasps Aker Reverse aker Recurved Extended Half and half Embrasure RPA Multiple Ring Back action Reverse back action T shape Half T U shape RPI C shape L shape I shape

I bar RPD : 

I bar RPD Kratochvil To reduce tooth contact of the retainer

I bar rpd Regular rpd : 

I bar rpd Regular rpd Mesial rest I bar retainer Long guide planes extending into tooth tissue junction Distal rest Occlusally approaching Normal guide planes

Design concepts : 

Design concepts Distal Mesial

Slide 11: 

Mesial rest --minor connector Major connector Reasons -elimination of harmful effects due to horizontal forces -mesial tipping -fulcrum line away from edentulous ridge

Slide 12: 

Proximal plates -additional proximal plate on distal surface -2-5 mm occlusogingivally -long guide plane Advantages: Increased horizontal stability Better retention Good reciprocation Distributes occlusal load uniformly across the arch

Slide 13: 

I bar -Modified bar or roach clasp -Long tapering arm with a half round cross-section -Placed on buccal surface of abutment, mesial to the mesiodistal height of contour -Should extend about 2 mm above the tooth tissue junction

Slide 14: 

Advantages -Minimal tooth coverage -Passive Disadvantages -Reduced retention -Less horizontal stability than its counter parts

Other parts : 

Other parts Major connector Minor connectors Denture base connectors

Slide 16: 

Modifications of I bar RPDs Rest, Proximal plate and I bar Rest, Proximal plate and Aker’s clasp

Rest, Proximal Plate and I-bar (RPI) : 

Rest, Proximal Plate and I-bar (RPI)

RPI uses : 

RPI uses Used for distal extension base partial denture & provide stress release. -Kennedy class I and class II

Modifications in RPI : 

Modifications in RPI Mesial rest modification -molars-triangular fossa -canines-mesial marginal ridge

Slide 21: 

Proximal plate modification -Design modification I marginal ridge to junction between cervical and middle third -Design modification II extends along entire length of proximal surface of abutment -Design modification III contacts just about 1 mm of gingival third of guiding plane of abutment tooth

Slide 23: 

I bar modification -Tip is pod shaped to allow more tooth contact -To compensate for the decreased encirclement

Slide 24: 

Advantages: -kinder on the abutment. -has stress-breaking action. -no stress on the tooth. -passivity

Thank you… : 

Thank you…

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