Abutment margin levels and residual cement occurrence in cement-retained implant restorations: An observational study

Abstract

Objectives To evaluate the association between different vertical levels of the abutment margin and residual cement prevalence in cement-retained implant restorations with customized abutments. Methods One hundred and nine single-unit cement-retained implant restorations with a screw-access channel were included. The crowns were intraorally cemented on the abutments, and excess cement was removed. The abutment-crown complex was unscrewed, and the abutment-crown complex and peri-implant tissue were photographed. Residual cement presence was recorded by dividing the abutment-crown complex and peri-implant tissue into four quadrants: mesial, distal, buccal, and lingual. The prevalence of residual cement was compared according to the height of the custom abutment margin of the corresponding quadrant. A multilevel model was used for statistical analysis (alpha = .05). Results Cement remnants were discovered on 72.48% of the dental implants. When the restoration quadrants were compared, cement remnants were present on 51.38%, 39.45%, 20.18%, and 17.43% of the mesial, distal, buccal, and lingual surfaces, respectively (p < .01). Regarding the abutment margin level, cement residues were found in 60.22% and 61.4% of the 0.5 mm subgingival and >= 1 mm subgingival margin groups, respectively, which were significantly more than those in the supragingival (23.65%) and equigingival (26.59%) margin groups (p < .01). After adjustment for confounding factors, the adjusted odds ratio (with 95% confidence interval) for residual cement in the subgingival margin groups was 3.664 (1.71, 7.852) when compared to the supragingival and equigingival margin groups. Conclusions The risk of residual cement occurrence was 3.66-fold higher with a subgingival abutment margin than with supragingival and equigingival abutment margins.