The effect of diode 980 nm laser-activated bleaching on surface roughness and color change in composite resin restorations (in vitro study)

This study aimed to evaluate surface roughness and color change in composite resin restorations following diode 980 nm laser-activated bleaching.

Thirty composite resin discs (5 × 2) mm were immersed in coffee and tea for one week each. Following immersion, discs were separated into three equal groups based on the bleaching procedure utilized, as follows: Group 1: bleached at home with 20% carbamide peroxide (CP); Group 2: bleached in-office with 35% hydrogen peroxide activated by an LED (LHP); and Group 3: bleached in-office using a diode 980 nm laser (DLHP). We calculated the mean surface roughness and mean color change. A paired T-Student test was employed to compare the mean surface roughness values in each group before and after bleaching. To compare means between groups, a one-way ANOVA was employed, followed by a post hoc Games-Howell’s test for pairwise comparison. The significance threshold was set at 0.05.

The home bleaching group (CP) significantly increased the surface roughness of composite resin restorations (P < 0.05). However, both in-office bleaching groups (LHP + DLHP) resulted in significantly lower surface roughness compared to the CP group. The CP group had a considerably larger mean color change compared to the in-office bleaching groups (P < 0.05).

In-office bleaching using a diode 980 nm laser did not affect the surface roughness of composite resin restorations. However, it caused a clinically apparent color change, similar to the effect of LED-activated bleaching.