How laser etching affects the clinical performance of a "no-wait" universal adhesive: 36-month results

To compare the 36-month clinical performance of a no-wait universal adhesive in non-carious cervical lesions (NCCLs) according to etching method and application mode.

Forty-one participants with at least five NCCLs received 215 restorations, which were randomly assigned to five groups according to five surface-conditioning and adhesive application protocols: Enamel and dentin etching with phosphoric acid (ED-A), selective enamel etching with phosphoric acid (SEE-A), self-etch (SE; control group), enamel and dentin etching with laser (ED-L), selective enamel etching with laser (SEE-L). Restorations were placed by a single operator using Clearfil Universal Bond Quick and Clearfil Majesty ES-2 and were evaluated at baseline, 6, 12, 18, 24, and 36 months using modified USPHS criteria. Survival was analyzed using Kaplan-Meier survival analysis with the log-rank test, and categorical outcomes were analyzed using Generalized Estimating Equations (GEE) (p < 0.05).

The 36-month recall rate was 97.5% (40 participants; 199 restorations). At 36 months, retention loss was greater in the ED-A group than in the SEE-A and SE groups and in the SEE-L group than in the SEE-A and SE groups (p = 0.036 for all comparisons). Marginal discoloration was greater in the SE group than in the ED-A and SEE-A groups (p = 0.022 and p = 0.004, respectively) and in the SEE-L group than in the SEE-A group (p = 0.014). Marginal adaptation was poorer in the SE group than in the ED-A, SEE-A, and ED-L groups (p = 0.001, p = 0.011, and p = 0.013, respectively). Marginal discoloration increased and marginal adaptation deteriorated significantly over time in all groups (p < 0.05).

Phosphoric acid enamel etching provided the most favorable long-term marginal performance, whereas the SE and selective laser etching protocols showed less favorable marginal behavior.