Clinical Performance of Two Luting Systems for Orthodontic Bracket Bonding

Objectives: Purpose of this study was to compare the short-term clinical retention of orthodontic brackets seated either with microfilled resin composite on a self etching adhesive or with hybrid-type luting resin after H3PO4 enamel etching. Methods: Ten patients were randomly chosen to have orthodontic brackets (Virage, American Orthodontics or Mini-Twins, Ortho-Organizers) bonded using iBond and Durafill VS (IBD, Heraeus Kulzer, Germany) in the UR and LR, and phosphoric acid and Advantage (ADV, Ortho-Organizers, USA) in the UL & LL quadrants. Teeth were cleaned with an abrasive paste in a rubber cup using a low speed handpiece. Two clinicians placed the brackets following the manufacturers instructions. Retention was evaluated after removal of the wires at baseline, 30, and 60 days, respectively. The effects of the two etchants were investigated on extracted incisors after abrasive paste cleaning (APC) followed by H3PO4 enamel etching (HPO) or iBond enamel conditioning (IBO), qualitatively by SEM and quantitatively by topography scanning (MicroProf Surface Analyzer, FRT, Germany) and surface roughness determination (STS). Results: One of the brackets luted with IBD debonded during initial ligating. The bracket was re-attached with the same system. None of the brackets was debonded at 30 or 60 days recall in either group. The SEM showed slight enamel pits and scratching after APC, deep prismatic etching patterns after HPO, and shallow patterns, rich in detail, after IBO. The surface roughness parameters Ra and Rz (µm) recorded after APC treatments were 0.23 and 2.72, following HPO 0.25 and 2.10, and after IBO conditioning 0.35 and 3.02. Conclusions: The clinical short-term retention results indicate that even the shallow etch pattern obtained with IBO is sufficient to retain brackets securely. Deep enamel etching with HPO is neither necessary nor desirable as it might lead to enamel damage during bracket removal.