Study design and settings
The current study was a split-mouth and double-blind longitudinal, prospective randomized clinical trial (RCT) with a follow-up of 12 months. Both the clinical examiner and the participant were blinded to the intervention. The Research Ethics Committee approved the research proposal (Ref. no. 419 on 27/6/2020). Furthermore, the research proposal has been registered in the The PICO query was posed, and the following constraints have been established: P: adult patients with two class II cavities; I: Bis-GMA free (pure ormocer) composite restoration; C: Bis-GMA containing (methacrylate) composite restoration; and O: evaluation of marginal integrity parameter according to USPSH criteria. The primary research inquiry addressed in this study was to determine if there is a similar level of marginal integrity between class II restorations created using pure ormocer composite and those made with methacrylate composite, as evaluated according to USPSH criteria?