A comparative 48 month randomized trial of clinical performance and wear of BISGMA based and BISGMA free nanoceramic resin composites

This study aimed to compare the 48-month clinical performance and wear of Bis-GMA-based and Bis-GMA-free nanoceramic resin composites in Class I posterior restorations. In a randomized clinical trial, 64 patients received occlusal restorations with either Zenit (Bis-GMA-based) or Neo Spectra ST (Bis-GMA-free) nanoceramic composites (n = 32). Clinical performance was evaluated using modified USPHS criteria at four timepoints (baseline, 12, 24, 48 months). Intraoral scans were analyzed using 3D digital superimposition techniques to assess linear and volumetric quantification of wear across follow-up periods. The results revealed that marginal discoloration was slightly more frequent in the Zenit group at 48 months, though not statistically significant. Clinical outcomes were comparable between groups. The amount of linear deviation measured in Zenit samples was higher than in Neo Spectra, whereas the volumetric deviation was greater in Neo Spectra. However, neither difference was statistically significant. Both composites demonstrated clinically acceptable performance over a 48-month period in Class I posterior restorations. Some marginal discoloration was observed with both materials. The differing matrix-to-filler ratios of the two nanoceramic resin composites may have contributed to compensating for volumetric wear. Intraoral scanning and digital analysis enable accurate, non-invasive wear monitoring. Neo Spectra ST offers superior esthetic stability and clinical handling. Neo Spectra™ ST may offer a clinically advantageous option for posterior restorations requiring esthetic durability and operator-friendly handling. Additionally, digital intraoral scanning combined with registration software provides a promising, non-invasive approach for monitoring restorative wear in clinical practice.Clinical trial registration: This study was registered on clinical trial ( http://www.ClinicalTrials.gov ) at February 4, 2021 with ID: NCT04738604.