A Three-step Etch-and-Rinse vs a Universal Adhesive in Nanohybrid Composite Anterior Restorations: A Retrospective Clinical Evaluation

Purpose: To retrospectively evaluate the clinical behavior of direct anterior composite restorations performed with a universal adhesive or with a three-step etch-and-rinse (E&R) adhesive. Material and methods: Patients were randomly treated with a three-step E&R adhesive (Optibond FL, Kerr) or a universal adhesive (Clearfil Universal Bond Quick, Kuraray Noritake) applied in E&R mode. All restorations were performed with a nanohybrid composite (ClearFil Majesty ES-2, Kuraray Noritake) by the same experienced operator. Two calibrated examiners evaluated the restorations using a dental mirror and explorer, in accordance with modified United States Public Health Service (USPHS) procedures. Clinical events were registered and classified as either failure (F), survival (SR), or success (S). Results: 168 restorations were evaluated in 90 patients with an average follow-up period of 37.9 (± 22.9) months. A total of 132 restorations were performed on vital teeth, and 36 were performed on endodontically treated teeth (ETT). A total of 128 Class-IV and 40 Class-III restorations were performed. In 89 restorations, a three-step E&R adhesive was applied (14 Class-III and 75 Class-IV), while in 79, a universal adhesive was used (26 Class-III and 53 Class-IV, p = 0.0091). A Cox regression analysis was performed (p < 0.05) to analyze which factors were involved in the failure of the restorations, considering failure (F) as restorations that needed re-intervention at the follow-up period of 37.9 (± 22.9) months. No statistically significant differences were observed when considering parameters directly involved with the adhesives tested. Endodontically treated teeth were more prone to fractures (p = 0.0006) compared to vital teeth. Restorations made with universal adhesives failed by fracturing significantly more frequently (p = 0.0234), while restorations made on endodontically treated teeth had a significantly worse outcome (p = 0.0001). Restorations made on canines also failed significantly more frequently (HR = 3.8, 95% CI = 1.4-10.1, p = 0.0062). Conclusions: Based on the obtained results, both the universal adhesive and the three-step E&R adhesive proved to be good treatment choices for direct anterior restorations after 37.9 (± 22.9) months of follow-up. Tooth vitality seems fundamental for the prognosis of a direct anterior composite restoration over time.