Effects of removing adhesive from tooth surfaces by Er:YAG laser and a composite bur on enamel surface roughnessand pulp chamber temperature

At the end of fixed orthodontic treatment, the remnant of adhesive should be eliminated from the tooth surface. The purpose of this study was to compare the effect of three methods of removing adhesive on enamel surface roughness, dental pulp temperature, and also on the time spent.

The brackets on 90 extracted teeth were debonded using bracket removal pliers. A thermocouple sensor was fitted on the buccal wall of the pulp chamber through access cavity to measure thermal changes during adhesive removal. The residue of adhesive was eliminated from enamel surface of teeth by either tungsten carbide bur, erbium-doped yttrium aluminum garnet laser, or fiber reinforced composite bur. Scanning electron micrographs images were taken to assess the roughness of enamel surface. The time spent for adhesive removal was recorded as well. Chi-square test was used to evaluate the remnants of adhesive and enamel surface roughness; t-test and also repeated measurement analysis of variance were applied at P < 0.05 to compare the thermal changes of the pulp chamber and time spent between the methods of surface treatment.

The results of surface roughness were significantly different (P < 0.001). The pulp temperature changed significantly (P < 0.001). Tungsten carbide bur increased the temperature by 5.5°C significantly slower than reinforced composite bur (P = 0.004), however removed the adhesive residue faster than two other methods although not significantly (P = 0.069).

Within the limitations of this study, fiber reinforced composite bur created the smoothest enamel surface while Er:YAG laser the roughest. Tungsten carbide and composite burs generated more heat compared to Er:YAG laser. In addition, tungsten carbide bur was the fastest and Er:YAG laser the slowest devices to remove adhesive residue.