Effect of different surface treatments on color and translucency of lithium disilicate restorations after Er;Cr:YSGG laser debonding: an in vitro study

Purpose: Due to the continuously expanding use of laser in debonding operations, the purpose of this study was to see how two surface treatments affected the optical properties of a lithium disilicate ceramic with two different thicknesses after Er;Cr:YSGG laser debonding. Methods: Twenty-eight freshly extracted bovine permanent incisors were prepared to receive lithium disilicate discs with 2 thicknesses (0.5 mm and 1 mm). The samples were bonded to the teeth and then debonded using Er;Cr:YSGG laser (2780 nm). The debonded samples were divided into two groups according to surface treatments: group 1 hydrofluoric acid etching HF (n = 14) and group 2 Er;Cr:YSGG laser etching (n = 14). Color and translucency were measured with a spectrophotometer before bonding and repeated after debonding and surface treatments. Color differences and translucency values were calculated using the CIEDE2000 color difference and TP formulas. The data were statistically analyzed. CIEDE2000 values > 0.8 and > 1.8 were considered perceptible and unacceptable, respectively. Results: There was a significant interaction between type of surface treatment and sample thickness (p < 0.001). Color change measured in 0.5-mm samples was significantly higher than that of 1-mm-thick samples (p < 0.001). Whether before or after surface treatments, 0.5-mm thickness showed statistically significantly higher mean TP than 1-mm thickness (p-value < 0.001). Conclusion: After debonding, different surface treatments had a discernible impact on the translucency and color stability of lithium disilicate restorations, to the point where debonded samples with 0.5-mm thickness displayed a perceptible and clinically unacceptable color change. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.