Clinical and OCT outcomes of a universal adhesive in a randomized clinical trial after 12 months

To assess the performance of a universal adhesive in different application modes in non-carious cervical lesions clinically and by optical coherence tomography (OCT).

55 adult patients with three non-carious cervical lesions (NCCL) each participated in the study. Lesions were restored with Scotchbond™ Universal (SBU, 3 M) applied in the self-etch (SBU-SE) and the selective-enamel-etch mode (SBU-SEE) in combination with Filtek™ Supreme XTE (3 M). OptiBond™ FL (OFL, Kerr) was used as a control. Restorations were clinically assessed (FDI criteria) after 14 days, 6 and 12 months and in parallel imaged by OCT (interfacial adhesive defects), starting immediately after filling placement. Cumulative failure rates (CFR) and means of interfacial adhesive defect were statistically evaluated.

After 12 months, CFRs were lower in the SBU groups (0.0% each) than in the OFL group (20.0%, p = 0.001). Clinically, small marginal fractures occurred three times more often in the SBU-SE than in the SBU-SEE group (p = 0.001). Immediately after filling placement and at each reassessment OCT revealed more interfacial defects at enamel interfaces for SBU/SE compared to SBU/SEE and OFL (p_i ≤ 0.044). At dentin/cement more defects were seen with OFL compared to SBU/SE and SBU/SEE (p_i ≤ 0.001). Before restoration loss, more interfacial defects appeared compared to remaining restorations (p_{immediately/6M} = 0.132/0.002).

Clinical evaluation and OCT imaging revealed higher interfacial integrity for SBU in both application modes compared to OFL. OCT detected interfacial bond failures prior to clinical deterioration or restoration loss.

Scotchbond Universal showed an equivalent or improved bonding performance compared to the reference adhesive. Selective enamel etching is recommended. The parameter interfacial adhesive defect seems to be a valuable predictor for evaluation of adhesive restoration systems.