Longevity of bulk fill and ormocer composites in permanent posterior teeth: Systematic review and meta-analysis

Purpose: To evaluate the clinical longevity of bulk-fill resins and ormocer composites compared to conventional nanofill and nanohybrid resins in posterior permanent teeth. Methods: PubMed, Web of Science, Scopus, Science Direct, Cochrane Library, and Scielo were electronically searched for randomized clinical trials, without language restrictions. The extracted data were analyzed using Review Manager, comparing the clinical behavior of bulk fill or ormocer restorations with nanofill or nanohybrid resins. Statistical analysis was performed with a significance level of 5% for all analyses (P= 0.05). The risk of bias was assessed using the Cochrane assessment tool. Results: 11 randomized clinical trials were included, with an average follow-up time of 40.36 months. A total of 812 restorations were evaluated and 58 failures were analyzed: 18 of the 253 bulk-fill restorations (7.11%), 21 of the 173 (12.3%) ormocer restorations, and 20 of the 386 (5.18%) control group (nanofill or nanohybrid composites) restorations failed. In the meta-analysis, there was no significant difference between the bulk-fill and the control group (statistical power = 24.38%; P= 0.206; IC = 95%); whereas, when comparing between ormocer and control group, the control group exhibited better performance (statistical power = 81.62%; P= 0.0042; IC = 95%).