Development of optical guiding forceps for a direct bonding system using lightcured resin adhesives

Multi-bracket systems are popular orthodontic appliances and are commonly bonded directly to enamel surfaces by resin adhesives. In light-cured bonding, the tip of the curing unit must be kept at a distance from the adhesive on the tooth, which can lead to low polymerization and insufficient bond strength. The curing lights also generate low-frequency electromagnetic fields, which can be harmful to patient health. Furthermore, bacterial contamination of the light-curing tips during use presents an infection risk for patients. In this study, we describe the development of optical guiding forceps (OGFs) for polymerizing light-cured resin as a solution to these problems. With OGFs, polymerization of adhesives was deeper than with lower magnetic fields and the bonds had the same shear strength as those formed by conventional procedures. These results suggest that OGFs may have practical use in the direct bonding of orthodontic appliances as well as in provisional bonding.