Evaluation of a New Self-Etching Adhesive for Orthodontic Bonding

The use of the newer single-step self-etching adhesives which etch, prime and apply the resin bonding agent simultaneously without rinsing, has been increasing in popularity in orthodontic bonding. Objective: The purpose of this study was to compare the bond strengths (MPa) and to evaluate the debonding site (ARI), when a conventional acid-etch conditioner and a self-etching adhesive system (Xeno® III) was used with either a composite resin adhesive (TransbondTM XT) or resin-modified glass ionomer cement (Fuji Ortho LC). Method: 120 extracted human premolars were mounted in acrylic resin and randomly assigned into 6 groups of 20 teeth each. Metal mesh-backed upper premolar brackets were bonded onto the mid-buccal surface of the teeth according to manufacturers instructions. 37% phosphoric acid, TransbondTM XT Primer and Adhesive comprised Group I. Xeno® III was used with TransbondTM XT Primer and Adhesive (Group 2), Group 3 consisted of Xeno® III and TransbondTM XT adhesive only. 10% polyacrylic acid conditioner with Fuji Ortho LC formed Group 4. Fuji Ortho LC was used with Xeno® III in Group 5 and also bonded on unconditioned enamel (Group 6). Shear-peel bond strength testing was performed after thermocycling (5°-55° C for 500X) with a Zwick 1440 Compression Machine. The data was analysed by ANOVA and Tukey, whilst the ARI scores (l0x magnification) analysed using Kruskal-Wallis. Results: The mean bond strengths (MPa) of the six groups were: 1=9.98, 2=9.52, 3=9.50, 4=6.53, 5=5.68, and 6=2.36. The results showed that the bond strengths achieved with Xeno® III were comparable to the traditional methods using either 37% phosphoric acid or 10% polyacrylic acid for both TransbondTM XT and Fuji Ortho LC. ARI scores showed less adhesive remaining on the tooth surface in Group 3. Conclusion: Xeno® III has the potential of being used to bond orthodontic brackets with the adhesives used in this study.