Relationship between Er, Cr: YSGG laser power and surface roughness of lased radicular dentin

Background. This study sought to assess the effect of Er,Cr:YSGG laser power on surface roughness of lased radicular dentin using atomic force microscopy (AFM). Methods. Fifteen human radicular dentin samples were randomly assigned to five groups: one control (G1, intact) and four experimental groups treated with 0.25-W (G2), 0.5-W (G3), 0.75-W (G4) and 1-W (G5) powers of Er,Cr:YSGG laser (2780 nm, 20 Hz, sapphire tip with 600-μm-diameter). After laser irradiation, surface topography was evaluated using AFM with a Si probe in tapping mode. Quantitative data regarding the arithmetic average roughness (Ra) and quadratic mean roughness (Rq) were obtained from three 5×5-μm areas of each sample. Data analysis was performed using one-way ANOVA (P<0.05). Results. The Ra and Rq values increased in G2 and G5 and decreased in G3 and G4 groups compared to the control group. The maximum Ra and Rq values were noted in G5, which were significantly higher than the corresponding values in G3 (P<0.05). Conclusion. No direct correlation was found between Er,Cr:YSGG laser power and surface roughness of lased radicular dentin. Laser therapy with a mean power of 0.5 W and 1 W resulted in the lowest and highest surface roughness, respectively.