Prosth 1: Interim RPDs and Flexible base RPDs

Interim RPDs

used while other dental treatment is being performed

Why other types of RPD's

need to minimize number of appointments, Ni allergy, aesthetics

When would an interim RPD be used

during establishment of caries control, healing, implant placement, unexpected loss of teeth, finances, occlusal support

Interim RPD retention

wrought wire embedded in acrylic

Interim RPD major connector

acrylic, also serves as denture base

Why can't an open plate or A-P strap be used with acrylic

acrylic isn't as strong as metal, will crack

What kind of mandibular major connectors not be used with acrylic

lingual bar, sublingual bar, or labial bar

Flipper

interim RPD replacing only 1 or 2 teeth

Advantages of interim RPD

quicker, cheaper, easy to modify, reline, add denture teeth and clasps

Why might interim RPD's cause accelerated periodontal decline if worn for years

no rests, so transmission of forces to alveolar ridge, no true rigid reciprocation

Flexible base/clasp RPDs

brand names valplast or flexiplast, introduced in 1950s

Flexible base material

polyamide, part of nylon family

How are flexible bases made

injection molding technique

Flexible base/clasp RPD advantages

aesthetics (no metal clasps), lightweight, better biocompatibility, stronger than acrylic, thinner major connectors

Flexible base/clasp RPD disadvantages

can be displaced easier, no cross arch bracing, no bonding to acrylic, more prone to staining

Can flexible base RPDs accelerate periodontal decline

yes, for the same reason as interim RPDs

Flexible base/clasp RPD delivery

hot water bath, flanges and clasps heated for 30-60 seconds and bent

Flexible base/clasp RPD modification with acrylic burs

need to be at lower RPM to not melt material