Evaluation of 18-Month Clinical Performance of CAD/CAM Hybrid Onlay Restorations Using FDI Criteria and QLF Imaging.

AIM: This study aimed to evaluate the 18-month clinical performance of indirect hybrid CAD/CAM onlay restorations using the FDI criteria, and to determine the correlation between clinical findings and fluorescence-based marginal analysis. MATERIALS AND METHODS: The retrospective study included 33 onlay restorations performed on posterior teeth using Grandio Blocs (VOCO, Cuxhaven, Germany). Thirty-three restorations and 58 surfaces (buccal/lingual) were evaluated at baseline (1-week) and at 18-months using FDI criteria across esthetic, functional, and biological domains. Standardized fluorescence measurements (ΔF and ΔR) at the restoration margins were obtained with a quantitative light-source fluorescence device (Qraypen C; AIOBIO, Seoul, South Korea) under controlled imaging conditions. Statistical correlation between FDI scores and fluorescence parameters was assessed. Data were analyzed using the Shapiro-Wilk, Wilcoxon Signed-Rank, Kruskal-Wallis, and Mann-Whitney U tests (p<0.05). RESULT: After a period of 18-months, all restorations were scored as clinically acceptable. No biological deterioration, such as secondary caries, was detected. Minor but statistically significant differences were observed in surface luster, surface staining, and marginal staining (p=0.025, p=0.046, and p=0.015, respectively). The findings demonstrate significant correlation between higher FDI scores for marginal staining and both ΔFaverage and ΔRaverage values (p<0.001). CONCLUSION: CAD/CAM onlay restorations demonstrate favourable 18-month clinical performance. QLF-based fluorescence analysis using Qraypen C® provides objective insight into early marginal deterioration, correlating well with clinical findings. Integrating fluorescence diagnostics provided additional information on marginal interface beyond conventional clinical inspection, supporting its potential value as an adjunctive tool in the routine monitoring of restorations.