Polymerization characteristics of light- and auto-curing resins for individual splints.

OBJECTIVES: The aim of this in vitro study was to assess different resins for occlusal splints regarding a number of polymerization characteristics. METHODS: One autopolymerizing resin (Palapress) and four light-curing resins (Acrylight, Primosplint, Triad TranSheet Colorless and Pink) were tested for flexural strength, modulus of elasticity, water sorption, volumetric shrinkage, and conversion of double bonds. These resins were polymerized for 10 and 15 min in a light oven at frequencies between 320 and 400 nm or 400 and 500 nm, respectively. Data were treated statistically by ANOVA and by Scheffé test. RESULTS: Concerning flexural strength and modulus of elasticity, Triad TranSheet Colorless showed significantly greater values than Primosplint and Palapress (p<0.05). The light curing resins Acrylight and Primosplint featured significantly higher water sorption when cured for 10 min compared to all other resins (p<0.05). Acrylight displayed significantly higher volumetric shrinkage and a higher quantity of remaining double bonds compared to all other light-curing resins (p<0.05). Primosplint, Triad TranSheet Colorless and Pink showed significantly lower shrinkage values than autopolymerizing Palapress (p<0.05). For all light curing resins, polishing of the samples resulted in a significantly lower quantity of remaining double bonds (p<0.05) compared to unpolished samples. SIGNIFICANCE: With respect to the polymerization properties evaluated, the light-curing resins reached similar material properties to the autopolymerizing resin or even surpassed them. Light-curing resins seem to be suitable for the fabrication of occlusal splints and can been seen as an alternative to autopolymerizing polymethylmethacrylates.