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

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.

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.

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.

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.