Comparison of the shear bond strength of reconditioned metal brackets used in indirect bonding: an in vitro pilot study

Abstract Objectives: This study aimed to compare the shear bond strength (SBS) related to surface treatment methods of debonded brackets before indirect rebonding and to evaluate changes in SBS related to sandblasting time. Methods: After brackets were debonded from a dental cast during an indirect bonding procedure, seven groups were assigned to conduct SBS tests. Sandblasted groups were sprayed with Al2O3 for 3 s (Group II), 6 s (Group III), 9 s (Group IV), and 12 s (Group V). In Group VI, a no. 4 round low-speed bur was used to remove resin. In Group VII, the bracket base was coated with a plastic conditioner (Reliance, IL, USA) and Group I served as the control group. Results: The SBS of Group VII was not statistically different from that of the control group. The SBS of Group VI was not statistically different from that of Group II but higher than that of the control group (P < 0.05). There was no statistical difference between Groups III, IV, and V, but was greater than the other groups (P < 0.05). Conclusion: The group with surface treatment by sandblasting for more than 6 sec prior to indirect bonding recorded a higher SBS than the other groups. The SBS did not increase further even if the sandblasting time increased by more than 9 sec.