Provisionals Flashcards
Ideal Properties of Provisional Materials
Convenient handling
Biocompatibility
Dimensional Stability
Ease of Contouring/polishing
Adequate strength and abrasion
Ideal Esthetic Properties of Provisional Materials
Good appearance
Good acceptability to patient
Ease of adding to or repairing
Chemical compatibility w/ luting agents
Acrylic Material
(Monomethacrylates) - Linear Chains. Tough and soft
Polymethyl methacrylate = Jet, duralay
Polyethyl methacrylate = Trim, Snap
BisAcryls Material
(Dimethacrylates) - Branched and crosslinked chains. Brittle/hard
BisGMA based (Provisa, Protemp)
Urethane dimethacrylate based (luxatemp)
Monomethacrylates usages
Provisionals
Custom trays
Dentures, RPD bases
Low end denture teeth
Polymer Formation
Causes shrinkage, reduced by adding fillers = PMMA/PEMA beads
Composition of Acrylics
Monomer
Powder
Monomer, inhibitors, chemical initiators (amine)
Polymer beads, colorants, chemical initiators (BPO)
BisAcryl Materials
Based on composite technology, flowable like
Dimethacrylate based
Advantages of BisAcryls
Good surface hardness
Good transverse strength
Easy to use
Low exothermic rxn
Low poly shrinkage
Good marginal fit
Good abrasion resistance
Minimal pulpal irritation
Good translucency and appearance!
Disadvantages of BisAcryls
Limited Shades (but can layer w/ composite)
Expensive
Brittle
Alteration and repair difficult
Fabricating External Surface Form
Alginate
Wax
Vacuum-formed acetate
Preforms
Indirect/direct
PVS
Shrinkage
Leave it on = lock it on
Take it out = wont seat
Leave it on but move it = 1-2 mm only
