Effect of Different Laser Irradiations on the Enamel Surfaces of Teeth Treated with Hydrogen Peroxide

Objectives: Objectives: Recently bleaching agents have gained more importance, because of the increased esthetical demands of many patients. In order to obtain better results with the available bleaching agents, lasers gained popularity with combination of applications. The aim of this study was to investigate whitening efficacy of two whitening agents in combination with two different photoactivation systems. Also, the changes in the micromorphology of the enamel surface after bleaching were evaluated.
Methods: Methods: Seventy two extracted human incisors were divided into two groups; Opalescence and Whiteness bleaching agents,containing 35% hydrogen peroxide. Then the samples of two groups were divided into six subgroups as follow: Group 1: Whiteness stimulated with erbium-doped yttrium aluminum garnet (Er:YAG) laser (WE), Group 2: Whiteness stimulated with low-power diode laser (WD), Group 3: Whiteness no light source stimulation was applied (WC), Group 4: Opalescence stimulated with Er:YAG laser (OE) Group 5: Opalescence stimulated with low-power diode laser (OP) Group 6: Opalescence no light source stimulation was applied (OC). After treatments, color change and enamel morphological alterations were evaluated. The statistical evaluations were done using two-way and one-way ANOVAtests in SPSS software.
Results: Results: There was statistically significant differences between bleaching agents and laser groups (p<0.05). There was statistically significant color change in all of the groups except WC group (∆E<3.3). Er:YAG laser stimulated Opalacence bleaching group gave a significantly higher ∆E (7.53) after treatment (p<0.05). Scanning electron microscopy showed no evidence of effects on the integrity of enamel.
Conclusions: Conclusions: The source of irradiation is more relevant than the bleaching agent for efficient tooth whitening. In addition, photoactivation with Er:YAG laser is effective at providing brighter teeth when assisted with Opalescence.