Comparison of Nanocomposite and Conventional Orthodontic Adhesives: A Prospective Study on Bracket Debonding and Enamel Discoloration

Introduction The success of orthodontic treatment depends on the adhesive performance of the bonding agents used to bond brackets to enamel. Conventional adhesives, such as Transbond XT (3M Unitek Corp., Monrovia, CA), have been widely utilized owing to their strong mechanical properties and clinical reliability. However, nanocomposites, such as amorphous calcium phosphate (ACP)-modified adhesives, have emerged as promising alternatives, offering potential benefits such as enhanced bond strength, remineralization properties, and better color stability. The present study aimed to compare nanocomposite and conventional adhesives in terms of bracket debonding rates and enamel discoloration over a six-month period. Materials and methods This prospective observational study was conducted in an orthodontic department between February and November 2024. Forty patients were included and divided into two groups: group 1 (n = 20 patients), where brackets (N = 400) were bonded using Transbond XT, and group 2 (n = 20 patients), where brackets (N = 400) were bonded using ACP-modified nanocomposite (Aegis Ortho, Bosworth Co. Ltd., Skokie, IL). All patients underwent the same orthodontic bonding protocol and were followed for six months. The bracket debonding time was recorded, and the change in enamel color (ΔE*) was assessed using a spectrophotometer (Vita Easyshade, Vita Zahnfabrik, Bad Säckingen, Germany). The Adhesive Remnant Index (ARI) was evaluated using a stereomicroscope at 20× magnification, and Kaplan-Meier survival analysis was used to assess bracket longevity. Statistical comparisons were conducted at p < 0.05. Results The mean debond time was 60.88 ± 20.68 days for Transbond XT and 66.58 ± 34.17 days for the nanocomposite group, with no significant difference (p = 0.876). The nanocomposite group showed lower color change (3.70 ± 0.50) compared to Transbond XT (3.95 ± 0.31), indicating better enamel color stability (p = 0.029). The nanocomposite group had more favorable failure modes, with a higher percentage of adhesive retention on enamel, reducing the risk of microleakage and enamel damage. Kaplan-Meier analysis suggested a slightly longer bracket survival in the nanocomposite group. Conclusion Nanocomposite adhesives exhibited bracket retention comparable to that of Transbond XT while demonstrating superior color stability and better ARI scores, indicating improved enamel adhesion and reduced enamel damage upon debonding. Given these advantages, nanocomposites are promising alternatives for orthodontic bonding.