Etch-and-rinse vs self-etch strategy of a universal adhesive in Class II bulk-fill restorations: A 96-month...

This randomized clinical trial investigated the 96-month clinical performance of a universal adhesive (Adhese Universal Vivapen, Ivoclar Vivadent) applied in etch-and-rinse (ER) and self-etch (SE) modes in Class II bulk-fill composite restorations.

Thirty-five patients, each with at least two Class II carious lesions, were enrolled. Using a split-mouth design, cavities were randomly assigned to ER or SE adhesive application. All restorations were placed with a high-viscosity bulk-fill resin composite (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent). In total, 84 restorations were evaluated at baseline and at 12, 24, 36, 48, 60, 72, 84 and 96 months by two calibrated, blinded examiners according to modified USPHS criteria. Statistical analyses were performed with Chi-square, Friedman, Cochran's Q, and McNemar tests (α=0.05).

At 96 months, 74 restorations in 33 participants were examined. No loss of retention/fractures occurred. Seven restorations were replaced (six due to secondary caries-ER: 1, SE: 5 and one due to unacceptable marginal adaptation-SE), yielding crude cumulative replacement rates of 2.4 % (ER) and 14.3 % (SE). Kaplan-Meier analysis showed significantly higher survival for ER than SE (97.4 % vs 85.2 %, p = 0.049). Marginal discoloration was consistently higher with SE from 36 months onward (p < 0.05), whereas marginal adaptation showed no differences between groups at any recall. Other criteria were comparable, and no postoperative sensitivity was recorded.

Despite a statistically higher incidence of marginal discoloration in the SE approach, both strategies demonstrated comparable long-term outcomes, with no retention loss after 96 months. The ER showed a higher cumulative survival. These findings confirm the clinical acceptability of universal adhesives in Class II bulk-fill composite restorations over extended service periods.

Universal adhesives demonstrated durable adhesion and predictable performance in posterior bulk-fill restorations with both strategies, while the ER approach provided additional benefits in marginal discoloration and lower cumulative replacement needs over the long term.