Comparison of surface roughness of enamel and shear bond strength, between conventional acid etching and erbium, chromium‐doped: Yttrium scandium‐gallium‐garnet laser etching - An in vitro study

The purpose of the study was to evaluate and to compare the shear bond strength (SBS), adhesive remnant index, and surface roughness of the samples bonded after etching with phosphoric acid and erbium, chromium‑doped: Yttrium scandium‑gallium‑garnet (Er, Cr: YSGG) laser.
In the present analytical/descriptive study, 90 premolars extracted for orthodontic purposes were used, out of which 75 were randomly divided into five groups where five different methods were used to prepare the enamel for bonding; etching with 37% phosphoric acid for 15 s, irradiation with Er, Cr: YSGG laser at 1 watt for 10 s and 20 s, and irradiation with Er, Cr: YSGG laser at 1.5 watt for 10 s and 20 s. Following this, metal brackets were bonded with Transbond XT. Brackets were debonded 24 h, later and SBS were measured, and adhesive remnant index scores were measured.
The remaining 15 teeth were used for surface evaluation of these five groups using three‑dimensional optical profiler. The results of the SBS testing, adhesive remnant index) scores, and surface roughness values were analyzed by one‑way analysis of variance and Tukey honestly significant difference tests with a significant level at 0.05.
The difference in bond strength between the laser (1.5 W/20 s) and conventional acid etching was not statistically significant (P > 0.05). For acid etch tech, it was 10.48 Mpa and Laser etch at 1.5 W/20 s 10.46 Mpa bond strength attained by the other groups (1 W/10 Hz, 1 W/20 Hz, and 1.5 W/10 Hz) was significantly less than acid etched, and laser etched (1.5 W/20 Hz) groups with P > 0.05. The surface roughness was found to be similar between the laser‑ (1.5 W/20 s) and acid‑etched groups (P > 0.05).
Irradiation with 1.5 W/20 s Er, Cr: YSGG laser produced bond strength comparable to acid etching.