RPD

1. The RPI System.

2. Contents
• Introduction
• Direct retainers
• Clasps
• I bar removable partial denture
• RPI

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

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

5. 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

6. 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

8. I bar RPD
• Kratochvil
• To reduce tooth contact of the retainer

9. 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

10. Design concepts
Distal
Mesial

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

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

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

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

15. Other parts
• Major connector
• Minor connectors
• Denture base connectors

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

17. Rest, Proximal Plate and I-bar (RPI)

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

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

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

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

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

25. Thank you…