Microstructural effect of a laser-activated bleaching agent containing titanium dioxide on human enamel

Abstract

Aim: This study aimed to evaluate the effect of a laser-activated bleaching agent containing titanium dioxide (TiO 2 ) nanoparticles on enamel roughness and hardness. Materials and Methods: Twenty human premolars were randomized into two groups according to the bleaching treatments performed: HP – 35% hydrogen peroxide and HP + TiO 2 – 30% hydrogen peroxide containing TiO 2 light-activated by diode laser (980 nm). It was performed two bleaching sessions with an interval of 7 days. Microhardness and roughness of the enamel were assessed at three times: T0 – Before 1 st appointment, T1 – after 2 nd appointment, and T2–7 days after 2 nd appointment. Results: The HP + TiO 2 did not cause changes on enamel roughness and hardness and presented the same effects of the HP. Conclusions: Both bleaching agents showed no difference between them. Then, it is possible to conclude that both are viable for clinical use during in-office dental bleaching technique regarding the microstructural changes that they might cause.

Effect of conventional and power office bleaching with diode laser and led light on enamel microhardness

“…With the development of lasers and other light sources used to activate bleaching agents 19 , the adverse effects of these sources on tooth hardness have not been reported. There are doubts about the role of these sources in increasing efficiency without damaging the structure of the tooth 20,21 .…”