In vitro Evaluation of Shear Bond Strength of Materials Used in Bonding 3x3 Lingual Retainer

Abstract

The aim of the present study was to evaluate which material and technique were the best for bonding 3x3 lingual retainer. One hundred and five bovine mandibular incisors were used, to which contention bars with a standardized size of 7 mm were bonded to the lingual surface. Initially all teeth received prophylaxis with pumice stone and water. After this they were randomly divided into seven groups, denominated and characterized as follows: Group (1) bars bonded with Transbond XT in accordance with the manufacturer's instructions; (2) Tooth surface etching with self-etching agent Transbond (SEPT) followed by bonding with Transbond XT; (3) Bonding with Transbond Plus Color Change (TPCC) without adhesive; (4) Bonding with TPCC + SEPT; (5) Bonding with restorative composite Z100 + adhesive Prime Bond, (6) Z100 without adhesive and (7) Z100 + SEPT. Before bonding in Groups 1, 3, 5 and 6 the lingual surface was etched with 37% phosphoric acid for 20 seconds, followed by washing and drying. After bonding the mechanical tests were performed in a Universal mechanical test machine. The values obtained were submitted to the analysis of variance (ANOVA) and afterwards to the Tukey test (p<0.05). We observed absence of statistical differences among Groups 1, 2, 5 and 7 and among Groups 3, 4, 5 and 6 (p<0.05). Group 1 presented the highest bond strength value and Group 6 the lowest. It could be concluded that where bonding of lingual retainer is concerned; the best material to use is Transbond XT irrespective of the etching method, followed by composite Z100 etched with SEPT.