Orthodontic bonding with varying curing time and light power using an argon laser.

Objective: To test the effects of curing time and light intensity on the shear bond strength of adhesive composites for stainless-steel orthodontic brackets.
Materials and Methods: An argon laser at four different power settings (100, 150, 200, and 250 mW) and four different exposure times (5, 10, 15, and 20 seconds) was used to bond adhesive-precoated (APC) stainless-steel incisor brackets to the facial surfaces of 154 bovine incisors. The shear bond strength of each specimen in 16 randomly divided groups was randomly tested to failure using an Instron universal testing machine. Each mode of failure was described using the adhesive remnant index (ARI).
Results: The ARI scoring system showed that the location of bond failure did not differ significantly in relation to exposure time (P = .40). However, the location of bond failure was significantly different in relation to light power (P = .03).
Conclusions: A short exposure time and a low power setting produce shear bond strengths equivalent to those produced by longer exposure times and higher power settings.