This in vitro evaluation analyzed the influence of custom base composite age on bond strength in indirect bonding. One hundred fifty permanent bovine mandibular incisors were randomly divided into 10 groups of 15 specimens each. Stainless steel brackets were bonded to the teeth using the Thomas indirect bonding technique using two different custom base composite-sealant combinations: (1) chemically cured Phase II composite and chemically cured Custom I.Q. sealant, and (2) light-cured Transbond XT composite and chemically cured Sondhi Rapid Set sealant. The composite custom bases were preaged for 24 hours and for seven, 15, 30, and 100 days. Shear bond strength tests for the two composite-sealant combinations showed no significant differences. Preaging of the custom base composite up to 30 days did not affect shear bond strength, and mean bond strength values exceeded 15 MPa in these groups. However, bond strength measurements for groups with a custom composite base aged for a longer interval (100 days) before sealant polymerization were significantly lower. On the basis of the results of this study, clinicians can safely use custom base composites aged up to 30 days when using the Thomas indirect bonding technique.
