Comparison of Enamel Surface Roughness between Light-cured and Self-cured Composites used in Orthodontic Bonding by using Atomic Force Microscopy

Abstract

Introduction: Debonding is a procedure of removing orthodontic attachments along with the entire residual adhesives from the surface of enamel following orthodontic treatment completion. The objective of the orthodontists should be to restore the surface of enamel as closely as possible to natural enamel without inducing iatrogenic injury and with minimal loss of enamel structure. Bonding of brackets on enamel involves surface etching, application of primer, and adhesive. All these steps involve the risk of damaging the enamel surface and changing its original morphology. Upon completion of orthodontic treatment, the debonding procedure followed by residual resin removal further damages the enamel, producing scratches, cracks, grooves, removal of fluoride-rich external enamel layer, and increasing the enamel roughness. The rough enamel surface inhibits proper cleaning and thus invites plaque deposition, bacterial retention, stain formation, and thus dampening the aesthetic appearance of the teeth. Restoring the enamel to its original morphology is a challenge. A variety of mechanical methods have been proposed to achieve satisfactory resin removal with least possible enamel damage following bracket debonding. The Enhance finishing and Pogo polishing system (Dentsply, Milford, USA) is also widely used and is made up of polymerized urethane dimethacrylate resin, aluminium oxide, silicon dioxide, and fine diamond powder. Methods: The sample of 50 tooth extracted for orthodontic purpose was procured as per the inclusion criteria. Buccal surfaces of teeth on the area where bracket is bonded and then debonding is done. After residual resin removal with Enhance system finishing and polishing bur. Measurements for each specimen were measured and mean was calculated and evaluated with the help of Atomic Force Microscopy (Baseline roughness data). Result: Self cure composite gives relatively lesser surface roughness when compared to light cure composites. Conclusion: The study shows that the self cure adhesive gives the smoother enamel surface when compared to the tooth treated with light cure adhesive after debonding and finishing and polishing.