Clinical and OCT assessment of application modes of a universal adhesive in a 12-month RCT.

Objectives: To evaluate a universal adhesive clinically using FDI criteria and by optical coherence tomography (OCT).

Methods: In 50 patients, three or four non-carious cervical lesions (NCCL) were restored with composite (Venus® Diamond Flow, Kulzer) using iBond® Universal (iBU, Kulzer) applied in self-etch (iBU-SE, n = 50), selective-enamel-etch (iBU-SEE, n = 29) or etch-and-rinse mode (iBU-ER, n = 50) and the reference OptiBond™ FL (OFL, Kerr, n = 50). Restorations were imaged by SD-OCT. The weighted mean length of interfacial adhesive defects (AD, %) was quantified per restoration immediately after placement (t), simultaneously with clinical assessment (FDI criteria) after 14 days (t), 6 (t) and 12 months (t). Data were statistically analyzed (McNemar-/Wilcoxon-/Mann-Whitney-U test (α = 0.05), Kaplan-Meier survival curves).

Results: After 12 months, cumulative failure rates were lower with iBU-SE (0.0%; p = 0.016), iBU-SEE (0.0%; p = 0.125), and iBU-ER (2.1%; p = 0.070; loss t) compared to OFL (16.7%; losses t, t). Generally, marginal adaptation decreased (p < 0.001) and marginal staining increased (p ≤ 0.031), without significant group differences (p > 0.064). AD increased in all groups (p < 0.001). At enamel, AD appeared more extended with iBU-SE vs. iBU-SEE (t-t; p ≤ 0.005), iBU-ER (t-t; p ≤ 0.051) and OFL (t-t; p ≤ 0.018). At dentin/cement iBU generally caused fewer defects than OFL (t-t; p ≤ 0.010) and with SE vs. ER (t-t; p = 0.010).

Conclusions: In NCCLs, iBU generally provides a more durable bond than OFL. Recommended mode is SEE. Clinic and OCT provided comparable results. OCT has higher statistical power, shows group differences earlier and specifically for the different hard tooth tissues.

Clinical Significance: The universal adhesive iBU was superior against the reference OFL in NCCLs. It can be recommended with SEE. Evaluation of interfacial adhesive defects by OCT seems to allow early prediction of adhesives' clinical performance.