Effect of deep margin elevation with different injectable materials on performance of CAD/CAM-Fabricated nanoceramic-resin onlays: 3-year randomized clinical trial

To evaluate the effect of deep margin elevation (DME) with four different injectable restorative materials on the three-year clinical performance of nanoceramic-resin CAD/CAM onlay restorations. Sixty-four adult patients with subgingival, broad Class II carious molars indicated for onlay restorations were randomly assigned to four groups according to the injectable DME materials used: highly viscous glass ionomer (HVGI), high-filled injectable composite resin (ICR), resin-modified glass ionomer (RMGI), and bioactive ionic resin (BAIR). The proximal subgingival margins were repositioned to a supragingival level using the assigned materials; subsequently, all groups received nanoceramic-resin CAD/CAM onlay restorations. Gingival health and restorative performance were assessed over a three-year evaluation period using the Gingival Index (GI) and modified World Dental Federation (FDI) criteria. The collected data were statistically analyzed. All restorations were evaluated with a 100% recall rate and a 100% survival rate. For GI, assessment of scores across various evaluation periods within each group revealed a significant increase over time. Nevertheless, no significant differences were found among the tested groups at each evaluation period. Additionally, FDI evaluation criteria showed no significant differences. After three years, nanoceramic-resin CAD/CAM onlay restorations following deep margin elevation with injectable restorative materials demonstrated acceptable clinical behavior, with only a slight increase in gingival bleeding. Injectable restorative materials can provide adequate clinical performance as deep margin elevation materials for molars restored with nanoceramic-resin CAD/CAM onlays.