Effects of occlusal loading and thermocycling on the marginal gaps of light-polymerized and autopolymerized resin provisional crowns.
BACKGROUND
Resin crowns appear to be increasingly at risk for increases in marginal gap size as a result of thermocycling and occlusal loading.


OBJECTIVE
This in vitro study compared the effects of occlusal loading and thermocycling on the margins of provisional crowns made from a conventional autopolymerized provisional acrylic resin (Jet) to those made from a light-polymerized resin (Unifast LC).


METHODS
Crowns made from the 2 materials were thermocycled and loaded on custom dies to simulate 6 to 8 weeks of oral function. Gap sizes were measured before and after thermocycling and occlusal loading.


RESULTS
Provisional crowns made from light-polymerized resin exhibited smaller changes in marginal gap size than did those made from conventional autopolymerized resin.


CONCLUSIONS
The improved characteristics of the light-polymerized material may prove useful for provisional crowns that must remain for long periods in the oral environment.
Dubois
R J
RJ
New Jersey Dental School, Newark, NJ 07103, USA.
Kyriakakis
P
P
Weiner
S
S
Vaidyanathan
T K
TK
D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D001732:Bite Force; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003794:Dental Restoration, Temporary; D006801:Humans; D008027:Light; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D003765:Models, Dental; D011108:Polymers / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013816:Thermodynamics
D000180:Acrylic Resins; D003764:Dental Materials; D008768:Methylmethacrylates; D011108:Polymers; C069716:Jet, dental resin; C078282:G-C Unifast LC