Thirty-six-month follow-up of cervical composite restorations placed with an MDP-free universal adhesive system using different adhesive protocols: a randomized clinical trial

Objectives To evaluate the influence of different application strategies on the clinical behavior of an MDP-free universal adhesive placed in non-carious cervical lesions (NCCLs) over the course of 36 months. Materials and methods Thirty-one patients participated in this study ( N = 31). One hundred twenty-four restorations were assigned to four groups: We used the self-etch strategy on groups with (SE-et) and without (SET) selective enamel etching, and the etch-and-rinse strategy on groups with dry (ER-D) and moist (ER-M) dentin. After applying the MDP-free universal adhesive (Xeno Select universal adhesive, Dentsply Sirona), cavities were filled using EvoluX composite resin (Dentsply Sirona). The restorations were evaluated at baseline and after 36 months according to World Dental Federation (FDI) and US Public Health Service (USPHS) criteria. Friedman’s repeated-measures analysis of variance rank ( α = 0.05) was used for statistical analysis. Results We evaluated the 31 patients after 36 months. Forty-two restorations were lost (ER-D = 5, ER-M = 7, SE-et = 14, SET = 16). The 36-month retention/fracture rates (95% confidence interval) were 83.9% for ER-D, 77.4% for ER-M, 54.9% for SE-et, and 48.4% for SET. ER strategy showed better retention rate than SE strategy ( p < 0.05). Thirty-four restorations (ER-D = 6, ER-M = 10, SE-et = 10, SET = 8) showed marginal staining per FDI criteria and 15 restorations (ER-D = 1, ER-M = 2, SE-et = 6, SET = 6) showed marginal staining per USPHS criteria. No restorations showed postoperative sensitivity or recurrence of caries. Conclusion The retention rate of Xeno Select universal adhesive was poor, mainly in the self-etch strategy. Trial registration REBEC clinical registry under protocol RBR-4wh4sh. Clinical relevance MDP-free universal adhesive behavior depends on the bonding strategy used.