Assessment of pulp chamber temperature changes following removal of residual adhesives beneath orthodontic brackets using a high-speed handpiece with and without water cooling

Introduction: An important consideration in fixed orthodontic treatment is potential adverse effects of debonding brackets and removal of remaining composite resins. One of the commonest methods of removing residual composite resin is the use of a bur, which might increase the pulp temperature. This study investigated temperature rise in pulp chamber after removing the remaining composite resins beneath orthodontic brackets using a high-speed handpiece under wet and dry conditions. Materials and methods: Forty wisdom teeth were used in this experimental research. After cleaning the tooth surfaces, the brackets were fixed by composite resin on buccal surfaces.  A palatal access cavity was prepared and a thermocouple was inserted in the cavity. Then the brackets were debonded. The teeth were randomly divided into two equal groups. In the first group, the remaining composite resin under the brackets was removed by means of a tungsten carbide bur in a high-speed handpiece without water. In the second group, it was removed in 10 seconds under water spray. The temperatures in the pulp chambers before and after removal of the residual composite resin were determined and the differences in both groups were documented as data. Data were statistically analyzed using independent t-test and paired t-test (α=0.05). Results: Removal of residual composite resin under dry conditions resulted in a significant increase in pulp chamber temperature (p value = 0.001). In contrast, use of water spray decreased pulp chamber temperature significantly (p value = 0.001). Conclusion: Under the limitations of the present study, it can be concluded that use of water cooling during removal of residual composite resin under orthodontic brackets with a high-speed hand-piece is preferable to dry conditions in relation to the effect on pulp chamber temperature.  Key words: Composite resins, Dental pulp cavity, Orthodontic brackets, Temperature.