THE COMPARISON OF SHEAR BOND STRENGTH OF 3D PRINTED PROVISIONAL RESTORATION REPAIRED WITH SELF-CURE RESIN USING VARIOUS SURFACE TREATMENT: IN VITRO STUDY

Abstract

This study aimed to evaluate the shear bond strength between 3D-printed provisional restorative materials (Temp C&B UV2.0 and Optiprint Lumina) and conventional self-cured provisional resin (UNIFAST™ Trad) with various surface treatments, and analyze the mode of bonding failure. A total of 192 specimens were included, each material group is further divided into 4 subgroups, each based on surface treatment as, No surface treatment (NT), Monomer application (MA), Sandblasting (SB), and Sandblast plus Monomer application (SB+MA). Each of the samples was bonded to UNIFAST™ Trad self-cure general-purpose material using a customized mold with an inner hole diameter of 5mm. The samples were stored in 95% humidity at 37˚C for 24 hours. A universal testing machine and digital measuring microscope were used to record shear bond strength and mode of failure. A two-way ANOVA displayed significant effects of material type, surface treatment, and their interaction on shear bond strength (p<.05). 3D printed (Temp C&B and Optiprint) materials demonstrated consistently lower shear bond strength compared to Unifast material across all surface treatments (p<.001). Surface treatment didn’t significantly influence Temp C&B, whereas Optiprint showed a noticeable increase in the bond strength when treated with the combination of sandblast and monomer application (p<.05). SEM images showed topography changes by sandblasting in all material group and fractography illustrated mostly mixed mode of failure in Optiprint Lumina under sandblast and combination group, whereas TempC&B group are mostly adhesive in nature. In conclusion, the effectiveness of surface modification of 3D printed provisional material was material-dependent, with only the Optiprint group having benefited from combined mechanical and chemical treatment.