Methods:~Recruitment Patients were recruited as they seek for treatment in the clinics of Dentistry of the local university. No advertisement was made for participant recruitment. Patients were recruited in the order in which they reported for the screening session, thus forming a sample of convenience.~Eligibility criteria A total of 183 participants were examined by two calibrated dental students to check if they met the inclusion and exclusion criteria.~Sample size calculation The annual retention rate to one-step self-etch adhesives in NCCLs was reported to be 4.4% in a recent systematic review. Considering that this decline follow a linear trend, the overall retention rate of one-step self-etch adhesives will be approximately 78% after 5-year of clinical service. With an of 0.05, a power of 80%, and a two-sided test, the minimal sample size will be 41 restorations in each group in order to detect a difference of equivalence of 15% among the test groups.~Interventions A total of 221 restorations were randomly placed in 35 patients assigned in four groups to two different etch-and-rinse two-step adhesive Peak® Universal Bond (P) (Ultradent Products Ind) and Single Link (SL) (Angelus Dental Products Industry).~The adhesives systems were applied on the NCCLs follows: P1 - applied according to the manufacturer's; P2X - applied for the double time; SL1 and; SL2X. The resin composite Amelogen (Ultradent) was placed incrementally. The restorations were evaluated imediataly (baseline), 6 and 12 months, using the FDI and USPHS criteria. Statistical analyses were performed using appropriate tests (=0.05).
Objective: This double-blind randomized clinical trial evaluates the influence of increased application time of a new etch-and-rinse two-step adhesive Single Link; (Angelus Dental Products Industry) applied in non-carious cervical lesions (NCCLs).~Methods: A total of 221 restorations were randomly placed in 35 patients assigned in four groups to two different etch-and-rinse two-step adhesive Peak® Universal Bond (P) (Ultradent Products Ind) and Single Link (SL) (Angelus Dental Products Industry). The adhesives systems were applied on the NCCLs follows: P1 - applied according to the manufacturer's; P2X - applied for the double time; SL1 and; SL2X. The resin composite Amelogen (Ultradent) was placed incrementally. The restorations were evaluated imediataly (baseline), 6 and 12 months, using the FDI and USPHS criteria. Statistical analyses were performed using appropriate tests (=0.05).