Effect of different surface treatments on repair bond strength of alkasite based restorative material

Abstract

Background This study investigates various surface treatment methods to assess shear bond strength between set Cention N (alkasite-based restorative material) and fresh alkasite based restorative material. Assessing different surface treatments provide insights in optimizing repair procedure that enables durability of the restoration, thus potentially benefitting clinical outcomes. Methods A total of 48 alkasite based restorative material blocks, measuring 4 mm in depth and 8 mm in diameter, were prepared. The samples were randomly divided into 8 groups (n = 6) according to the surface treatment done. Group I: Surface preparation by bur; Group II: Surface treatment by laser; Group III: Application of 2-step etch and rinse adhesive (Adper Single Bond 2 adhesive),Group IV: Application of single step self-etch adhesive (Scotchbond Universal adhesive); Group V: Bur preparation followed by application of 2-step etch and rinse adhesive; Group VI: Bur preparation followed by application of single step self-etch adhesive; Group VII: Laser preparation followed by application of 2-step etch and rinse adhesive; and Group VIII: Laser preparation followed by application of single step self-etch adhesive. Post-surface preparation, all the specimens were restored with freshly mixed alkasite material. All samples were then subjected to repair bond strength measurements using a universal testing machine. ANOVA with post-hoc Games-Howell test and two-way ANOVA with post-hoc Bonferroni test was performed to evaluate the influence of surface preparation on the repair bond strength. Results Among the various surface treatments, use of a 2-step etch and rinse adhesive resulted in a higher repair bond strength compared to other surface treatments, whereas roughening of the surface using burs resulted in the lowest repair bond strength (P=0.02). Conclusion Application of 2-step etch and rinse adhesive to the existing alkasite based restorative material provides superior bonding with the freshly added alkasite based restorative material.