Improving clinical retention of one-step self-etching adhesive systems with an additional hydrophobic adhesive layer.

Background: The durability of restorations bonded with one-step self-etching (OSSE) adhesive systems is inferior compared with that of restorations bonded with conventional adhesives. The authors conducted an 18-month randomized clinical study to evaluate the clinical performance of two OSSE systems in noncarious cervical lesions applied as recommended or with an extra layer of hydrophobic adhesive layer after 18 months of clinical service.
Methods: Thirty participants, each of whom had at least two pairs of similar-sized noncarious cervical lesions, took part in this study. The authors placed 120 restorations, 30 in each of four groups: Clearfil S3 Bond (Kuraray, Osaka, Japan) (CS) and iBond Gluma inside (Heraeus Kulzer, Hanau, Germany) (IB), and Clearfil S3 Bond (CSB) and iBond Gluma inside (IBB) with an extra layer of hydrophobic adhesive applied on top of them. They placed the restorations incrementally, using a resin-based composite. The authors evaluated the restorations at baseline and at 18 months following modified U.S. Public Health Service criteria.
Results: At 18 months, the retention rate for the IB group was statistically lower than those for the CS, IBB and CSB groups. Marginal discoloration occurred in all groups and was statistically worse in the IB group.
Conclusions: The conversion of the iBond Gluma inside and Clearfil S3 Bond adhesive systems into two-step systems by means of applying an extra hydrophobic adhesive layer improved the clinical performance of these materials after 18 months of clinical service.
Clinical Implications: The application of an extra hydrophobic adhesive layer over OSSE adhesive systems, layers improved the OSSE systems clinical performance, mainly in terms of retention rate.