In vitro evaluation of shear bond strengths and in vivo analysis of bond survival of indirect-bonding resins.

In this study we evaluate the shear bond strengths (SBS) of indirect-bonding systems available on the market. For the in vitro study, 60 extracted premolars were divided into three groups. In indirect group I, the brackets were bonded to models using Therma Cure laboratory resin and transferred to the teeth using Custom IQ resin for indirect bonding. For indirect group II, the teeth were attached to models using Transbond XT and transferred using Sondhi Rapid Set. In the direct-bonding group, the brackets were bonded to teeth directly using Transbond XT The SBS were evaluated, and the comparisons were made. In the in vivo study, left half of the upper arch and right half of the lower arch were bonded using Sondhi's indirect-bonding resin and right half of the upper arch and left half of the lower arch were bonded using Therma Cure as a laboratory resin and Custom IQ as a clinical bonding resin. The failure rates of the brackets were followed for nine months. Analysis of variance and Tukey tests were performed. Mean SBS values (MPa) were 10.3 +/- 4.2, 6.1 +/- 1.6, and 12.8 +/- 5.4 for the indirect groups I and II and for the direct-bonding group, respectively. There were no significant differences between indirect group I and direct group (P > .05), whereas both yielded significantly higher SBS values compared with indirect group II. In vivo bond survival evaluation showed no differences between the two indirect-bonding systems available.