A comparative evaluation of lingual retainer failure bonded with or without liquid resin A randomized clinical study with 2-year follow-up

Objective: To prospectively evaluate and compare the effect of liquid resin on lingual retainer failure after a 2-year follow-up. Materials and Methods: Fifty-two patients (26 males, 26 females) with a mean age of 18.3 +/- 1.3 years at follow-up, were randomized into two groups: the resin group and the nonresin group. The lingual retainers in the resin group were bonded to the enamel surfaces with two-step bonding resin, Optibond FL, and Tetric EvoFlow. The nonresin group followed the same procedure of bonding retainers but without applying the Optibond FL. Retainer failure, calculus accumulation, and discoloration of composite pads adjacent to the retainers during the 2-year observation period were registered, compared, and statistically analyzed with a Fisher's exact test and chi-square test. Results: In the resin group, the incidence of retainer failure was 4% and occurred at the composite-wire interface; in the nonresin group, the incidence was 27% and occurred at the enamel-composite interface. The difference between the groups was statistically significant (P =.049). The incidences of calculus accumulation and discoloration adjacent to the composite pads were 27% and 69% (P =.003 and P <.001) higher in the nonresin group, respectively. Conclusion: Application of resin in bonding of lingual retainers appears to reduce the incidence of retainer failure as well as the incidence of calculus accumulation and discoloration adjacent to the composite pads. (Angle Orthod. 2012;82:84-87.)