An in vitro investigation on the reinforcing potential of contemporary composites in weakened bicuspids

CONTEXT: This study was carried out to assess the currently available composite systems in India for resistance to fracture in teeth with large cavities. AIM: To evaluate the fracture toughness of weakened maxillary premolars restored by contemporary composites. SETTINGS AND DESIGN: In-vitro study was done in the department of conservative dentistry and endodontics. MATERIALS AND METHODS: Freshly extracted 44 human maxillary bicuspids were randomly divided into four groups where Group I included intact teeth. The teeth in the other three groups were subjected to a standardized mesio-occluso-distal cavity preparation. The cavities were filled in Group II with bioactive, nanohybrid composite with Giomer chemistry (Beautifil II LS, Shofu Inc., Kyoto, Japan), in Group III with highly filled, nanohybrid composite (Prevest Fusion Universal, Prevest DenPro Limited, Jammu, India) and in Group IV with fiber-reinforced composite with optimized fiber-aspect ratio technology (everX Posterior, GC EUROPE N. V., Leuven, Belgium). All the specimens were then subjected to thermocycling followed by incubation procedures. Fracture resistance was measured in Newton (N) using the universal testing machine. STATISTICAL ANALYSIS USED: Data obtained were tabulated and subjected to one-way analysis of variance (ANOVA) test followed by Tukey's test. RESULTS: Highest mean fracture resistance was observed with Group I (2294.06), followed by Group II (1708.72), Group IV (1195.82), and Group III (825.38). One-way ANOVA test showed a statistically significant difference (P ≤ 0.05) between all the four groups. Post hoc Tukey test was used for intergroup comparison and showed significant difference (P ≤ 0.05) in mean fracture resistance between groups. CONCLUSION: The results suggest that the highest compressive fracture resistance was shown by Group II (Beautifil II LS composite resin).