The Effect of Diode Laser Irradiation on Surface Roughness of Bleached Enamel: An in Vitro Study

Aims: To evaluate the influence of post bleaching diode laser irradiation on the surface roughness of bleached enamel. Materials and methods: Forty bovine teeth were prepared and then randomly divided into two equal groups (n=20) according to the in–office bleaching technique as follows: CB: Conventional in–office bleaching technique LB: Laser–assisted in–office bleaching technique. Each group was then subdivided into two subgroups (n=10) according to laser irradiation setting as follows: C2: Conventionally bleached followed by 2-Watt laser irradiation, C4: Conventionally bleached followed by 4-Watt laser irradiation, L2: Laser–assisted bleached followed by 2Watt laser irradiation and L4: Laser–assisted bleached followed by 4Watt laser irradiation. Surface roughness was assessed three times for all the specimens: before bleaching, 24 hours after bleaching and finally 24 hours after post bleaching diode laser irradiation by utilizing profilometer. Paired samples t–test and independent samples t– test was utilized for statistical analysis at p≤0.05. Results: Both bleached groups exhibited a significant increase in the surface roughness of enamel with no statistically significant difference between them. Post bleaching diode laser irradiation at 4Watt resulted in a significant increase in surface roughness of enamel, while 2Watt diode laser irradiation resulted in non–significant increase in surface roughness of enamel. Conclusions: In–office bleaching techniques had a negative impact on enamel in terms of surface roughness. Post bleaching diode laser irradiation at 2Watt power parameter is more preferred than 4Watt power parameter.