Fracture resistance of premolars teeth restored by silorane, nanohybrid and two types of fiber‑reinforced composite: an in‑vitro study

Objective The objective was to evaluate and compare the fracture resistance of human maxillary premolars teeth restored with low shrinkage microhybrid composite Silorane‑based; Filtek P90 LS, conventional methacrylate‑based nanohybrid composite; Ceram X Mono, and two types of fiber‑reinforced composites (FRCs); Alert and XENIUS base, micro glass fibers and short glass fibers, respectively in mesio‑occluso‑distal cavities. Materials and methods A total of 45 human maxillary premolars were selected. Standardized mesio‑occluso‑distal cavities were prepared in all teeth. Five prepared teeth received no treatment and served as controls (group 1). A total of 40 teeth were randomly divided into four experimental groups (n = 10); group 2: low shrinkage Silorane‑based composite, group 3: nanohybrid resin composite, group 4: microfibers reinforced resin composite, and group 5: short fibers reinforced resin composite. Restorations were done for all groups. After being stored 24 h at 37°C, fracture resistance was measured in a universal Instron testing machine by using a 4 mm diameter steel sphere which was applied on tooth buccal and lingual cusps at a cross‑head speed of 2 mm/min until fracture occurred. Statistical analysis One‑way analysis of variance and Tukey’s post‑hoc test. Results Highest mean fracture resistance was observed with FRC, nanohybrid, Silorane and lastly with control respectively. Statistically Significant difference was revealed by analysis of variance (P ≤ 0.0001) and Tukey’s post‑hoc test (P ≤ 0.0001). Conclusion Among the experimental groups, FRC showed the highest fracture resistance.