Objective: This study tested the potential hampering effects of acidic sulfur compounds (ASC) containing hydroxybenzene sulfonic acid, hydroxymethoxybenzene sulfonic acid and sulfuric acid, prior to self-etch and etchand-rinse bonding procedures on enamel and dentin. According to the manufacturer, ASC should be applied after cavity preparation and prior to application of a primer in order to reduce the remaining biofilm in the preparation cavity. Despite promoted marketing, data on the investigated liquid are almost completely lacking. Material and Methods: One-hundred-and-fifty-two extracted mandibular bovine incisors were embedded and polished to expose either enamel (E) or dentin (D). Then, specimenswere randomly divided and conditioned as follows (n=12/group): ASC and consecutive phosphoric acid application (E1/D1), ASC (E2/D2; E5/D5), phosphoric acid (E3/D3) and no conditioning (E4/D4; E6/D6). Groups were then treated with either Optibond FL® (etch-and-rinse; 1-4) or Clearfil SE Bond® (self-etch; 5-6).Hollow acrylic cylinders were bonded with a hybrid composite resin (Filtek Supreme XTE®) to the specimens and the shear bond strength was measured (1mm/min). In addition, failure types were assessed. Descriptive statistics and statistical analyses were performed with one-way ANOVA followed by the Scheffé post-hoc test. Results:For enamel, the highest shear bond strengths values were obtained applying routine bonding procedures (23.5 ± 5.6 MPa for etch-and-rinse and 26.0 ± 6.0 MPa for selfetch respectively). In contrast, dentin pre-treatment with a combination of ASC and phosphoric acid led to the highest shear-bond values (22.8 ± 4.1 MPa). Conclusion:This study shows that ASC prior to dental restoration placement cannot be recommended for etch-and-rinse procedures on enamel, but is appropriate for dentin without interfering with routine bonding procedures.
Clinical Relevance:The application of acidic sulfur compounds prior to adhesive restoration placement should be restricted to dentin only as it may negatively influence shear bond strength on sound enamel.