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In vitro evaluation of surface characteristics comparing WaterLase (Biolase®) with tungsten carbide burs for composite removal: a pilot study

Abstract Introduction The present ex-vivo study was designed to evaluate the surface roughness and analyse potential adhesive remnants on the enamel surface after composite removal using either an Er:YSGG WaterLase (WL) (Biolase®, Irvine, CA, USA) or a tungsten carbide (TC) bur (Alston, England, UK). Methods An in vitro study was designed using 21 extracted lower premolars. Pre-coated stainless steel brackets (3M Unitek, Monrovia, CA, USA) were bonded on all of the teeth except one, which served as a control. The teeth were allocated into two groups: Group 1 (n = 5), removal of composite with a TC bur. Group 2 (n = 15), removal of composite using the WL. Scanning electron microscope (SEM) imaging and Energy Dispersive X-ray Spectroscopy (EDS) were used to determine the surface roughness and atomic composition of the surfaces. Results Group 1 had a median damage depth of 17.6 µm with a range between 11.5 µ m and 28.7 µ m. Group 2 had a median damage depth of 166.3 µ m, with a range between 86.6 to 263.1 µ m. The depth differences between the two groups were statistically significant (p < 0.001, Mann–Whitney test). The atomic composition of the WL group was similar to sound enamel. The TC group showed a quantitative increase in carbon and silicone by 38.2% and 11.5%, respectively, a decrease in oxygen by 44.1% and an absence of phosphorous and calcium. Conclusion WL is efficient at removing composite from the enamel surface but could result in increased enamel surface roughness in comparison with conventional TC burs.