An Intra-Patient Cohort Study on the Effect of Resin-Cement Types on Cement Remnants in Implant-Supported Restorations

Abstract

OBJECTIVES: The choice of retention mechanism in implant-supported restorations (ISRs) strongly influences biological outcomes, with cement-retained ISRs linked to peri-implant complications due to excess cement. Factors such as crown design, margin location, and cement type affect the extent of residual cement and its clinical implications. MATERIAL & METHODS: This prospective, two-arm, non-randomized clinical trial compared cement remnants of self-adhesive resin (RC) and resin-modified glass ionomer (RMGIC) cement in 30 patients, and 60 ISR. Comparisons were performed on identical pairs of ISR tested within the same patients with a 1-week healing interval. The primary outcome variable was the ratio of cement-covered area to total crown area. Areas were analyzed ex-situ by standardized digital image analysis. Statistical analyses included descriptive statistics, Wilcoxon Signed Rank and Kruskal-Wallis tests. RESULTS: All specimens showed remnants of residual cement. In the crown-abutment interface, residual cement was detected on all four crown surfaces and for both types of cement, with total relative cement-covered areas ranging from 0.3% to 11.7% and average values between 1.5% (± 0.7%) and 2.0%. (± 2.4%). RMGIC resulted in higher cement residues than RC in all surfaces except the buccal surface, with differences reaching statistical significance in mesial sites (p=0.007). Other surface comparisons showed no statistical significance. CONCLUSIONS: RMGIC resulted in higher residue areas than RC. Within the limitations of this study, cement remnants appear to be unavoidable through standard clinical procedures, emphasizing the need for case-specific choice of the retention mechanism for ISRs. Screw-retained ISRs present a viable alternative.