Clinical performance of different composite materials in class II cavities bonded with universal adhesives

Objective: To assess the clinical performance of two composite materials with two universal adhesives and a two-step self-etch adhesive on class II restorations for 18 months. Materials and Methods: Two hundred and fifty-two class II cavities were bonded with G-Premio Bond, Single Bond Universal, and Clearfil SE Bond 2. A nanohybrid composite (Filtek Z550 Universal) or a microhybrid composite (G-aenial Posterior) was used to fill the bonded cavities. World Dental Federation criteria were used to evaluate the restorations at 1 week, 6, and 18 months. Statistical analysis was performed using Friedman and Fisher's exact tests (alpha = 0.05). Results: Retention loss and fracture were not observed in any restorations during the 18 months. The adhesives used showed no significant differences for all criteria examined (p > 0.05) regardless of composite material. After an 18-month follow-up, seven G-aenial Posterior and three Filtek Z550 Universal restorations presented slight marginal discrepancies, with no significant differences (p = 0.246). At 1 week, Filtek Z550 Universal (9.5%) led to significantly higher postoperative sensitivity compared with G-aenial Posterior (0.8%) (p = 0.001). Conclusions: Universal adhesives showed similar clinical performance to Clearfil SE Bond 2. The restorations with Filtek Z550 Universal had a relatively higher risk of postoperative sensitivity.