In vitro comparison of debonding force and intrapulpal temperature changes during ceramic orthodontic bracket removal using a carbon dioxide laser

Abstract

The aim of this study was to develop a method to reduce the fracture of ceramic orthodontics brackets during debonding procedures. Lasers have been used to thermally soften the bonding resin, which reduces the tensile debonding force. Thermal effects of lasers may create adverse effects to the dental pulp. Previous studies have shown that no pulpal injury occurs when the maximum intrapulpal temperature rise stayed below 2 degrees C. This study investigated the effect of lasing time on intrapulpal temperature increase and tensile debonding force with a 18 watt carbon dioxide laser. Ceramic brackets were bonded to mandibular deciduous bovine teeth and human mandibular first premolars with a photoactivated bonding resin. Modified debonding pliers was used to accurately position the laser beam onto the ceramic bracket. Lasing time required to keep the maximum intrapulpal temperature rise below 2 degrees C was determined by the use of thermocouples inserted into the pulp chambers of the specimens. A tensile debonding force was applied on the control group without lasing and the experimental group was debonded after applying a predetermined lasing time with a carbon dioxide laser. It was found that there was a significance difference (P < 0.05) in tensile debonding force between the control group and the experimental group. It is feasible to use a laser for the debonding of ceramic brackets while keeping the intrapulpal temperature rise below the threshold of pulpal damage.