Lec 2/9 Retainers for RPD Flashcards
Need for retainers or partial RDP?
to modify dentition by enameloplasty and/or addition of composite resin for min prep, cast restos w GPs, rest seats, retentive UC’s or precision attachments
Factors when considering to crown:
caries, existing restos, vitality , shape/ long axis of tooth, OH of pt, pdd, cost, experience of dentist
TF? Must do full coverage restorations for abutment if endo needed
T
Cheapest option for rest seats:
amalgam
Purpose of surveying casts:
alignment of LA of teeth that support partial, POI, eval tissue UCs and their influence on design
Seq of surveying:
occ table parallel to platform, GPs - AP, retentive areas - laterally, check for bony UC’s
Seq of making retainers for RDP:
survey study cast, dx, tx plan, design retainers (clasps, rest seats, etc? check) and RPD, mouth prep, snapstone cast to verify, survey crown prep and impression of cast restoration, interocclusal record, definitive cast and die, wax up, lab order (tripod marks, specs, design w both sigs), casting, resurvey retainers, cement, RPD impression
How many times should a survey crown be surveyed?
at least 4
Which is done first, preparation of the rest of the mouth or preparation of the survey crown tooth when making retainers fro RPD?
preparation of the rest of the mouth: tooth mods, GPs, HOC, rest
Why are you surveying the 2nd time?
to verify tooth mods
Order of tooth mods:
GPs, axial contours, occlusal rests
Order of wax mods for survey crown:
Gps, retention/reciprocation, rests
Which arm of clasp should engage toth first?
reciprocal before retentive
BL width of rest seat:
1/2X
4 times to survey w survey crown fabrication:
study cast, survey to verify tooth mods, survey after final tooth prep, survey after crown returns from lab and before delivery in cast mods need to be made
What to do if CCC survey crown needs adjustments after being surveyed and before delivery:
mill
How to make a crown under an existing RPD:
tooth prep, impression, seat existing RPD, filled tray “picks up” partial in final impression
Can a crown be made under an existing RPD digitally?
yes
TF? RPD attachments are the same for existing tooth, crown and implants.
F, diff for implant
Adv of implant supported partial:
esthetic, no clasps in anterior portion, retentive part in PRD
Advantage of intracoronal attachment for RPD vs occlusal rest:
forces applied along LA of tooth, closer to fulcrum, more apically, and dissipated
Benefits of force application closer to the fulcrum of tooth in intracoronal attachments:
red non axial loading, dec torquing forces, rotational movement of the abutments
“Philosophy” for attachments for RPD in distal extension base cases:
“Broken Stress Philosophy”
“Broken Stress Philosophy”:
Red stress to abutments bc it has stress free rotational/ vertical movements, applies different types of forces on the last retainer
