A comparative study of the fit and retention of interocclusal splints constructed from heat-cured and autopolymerized...

Fifty-three subjects each had a single Michigan splint constructed of either heat-cured or autopolymerized polymethylmethacrylate. The choice of material was decided randomly. A blind assessment for fit and retention was used on a three-point scale. Fit and retention were apparently unaffected by the material used. Thirteen percent of splints were unsatisfactory for clinical use (poor fit or retention) and this was also independent of material. A small number of splints contained structural faults (voids, porosity, or cracks) that may shorten the clinical life of these restorations; 9 of 12 such faults occurred in the autopolymerized group. Previous research has shown that conventional heat-cured polymethyl-methacrylate has superior properties compared with autopolymerized resin. In the absence of differences in accuracy of fit or retention, a heat-cured material is therefore advised where splints are intended for long-term clinical use.