Periodontal Evaluation of Subgingival Open Sandwich Restorations: 2-Year Results of a Randomized Double-Blind Trial.

This study aimed to evaluate the periodontal responses of subgingival proximal margins elevated using different restorative materials. A total of 120 proximal cavities with dentin/cementum gingival margins were elevated using one of four materials (resin-modified glass ionomer, glass hybrid, flowable bulk-fill resin composite, or bioactive ionic resin) and completed with the same overlaying resin composite. At 2 weeks (baseline), 6 months, 1 year, and 2 years postrestoration, periodontal parameters and the radiographic distance between the restoration margin and bone crest were evaluated. Appropriate statistical analyses were performed. The values of all periodontal parameters increased with time, although only the increases in Plaque Index and probing depth within each material group were statistically significant. There were no statistically significant differences in any of the periodontal parameters between the different materials within the same evaluation period, nor between different time points or material groups in the radiographic distances. Both glass ionomer-based and resin-based materials were periodontally safe as subgingival open sandwich restorations.