Influence of different types of resin cement on the fracture resistance of teeth restored with MOD ceramic inlays

Abstract

The purpose of this study was to evaluate the influence of 3 different types of resin cements on the failure of teeth restored with ceramic inlays using a universal testing machine. Seventy-five intact, caries-free human maxillary premolars were divided into 5 groups cavity preparation and restoration with IPS e.max CAD by Variolink N; Group 3, MOD cavity preparation and restoration with IPS e.max CAD by RelyX Unicem; Group 4, MOD cavity preparation and restoration with IPS e.max CAD by Multilink sprint; and Group 5, MOD cavity preparation and no restoration. Compressive force was loaded only on the cuspal inclination of tooth. Class II MOD preparation was as follows. The pulpal floor was formed at a depth of 2 mm from the occlusal cavosurface margin of the preparation, and the isthmus was half of vi the intercuspal distance. The proximal box width was 1.5 mm, and the axial wall was 2 mm in height. Margins were prepared with 90-degree cavosurface angles. Specimens were tested with a universal testing machine at 1.0 mm/min using steel sphere plungers (6.0mm in diameter). Peak load to fracture (N) was measured for each specimen. Means were calculated and analyzed with a one-way ANOVA and Tukey’s test (α=0.05). The mean peak fracture loads (N, mean ± S.D.) were as follows: Group 1 - 1371.29 ± 455.86, Group 2 - 1188.18 ± 408.79, Group 3 - 1097.38 ± 443.64, Group 4 - 1134.69 ± 352.13, Group 5 - 624.08 ± 259.03. Based on the results obtained under in vitro experimental conditions, the following conclusions were drawn. There was no statistical difference of fracture load between intact teeth and restored teeth. Although Group 2 (Variolink N) showed superior fracture load than Group 3 (RelyX Unicem) and Group 4 (Multilink speed), no statistical difference was found. Groups 3 and 4, using self adhesive resin cements, showed unfavorable fracture patterns more frequently than Groups 1 and 2. Fracture resistance of teeth restored with ceramic inlays was comparable with that of intact teeth, regardless of the type of resin cements used in this experiment.