Comparing effectiveness of rubber dam and gingival displacement cord with copy abutment in reducing residual cement in cement-retained implant crowns: A crossover RCT.

Objective: To evaluate the amount of residual cement after cementation of implant crown abutments with rubber dam and retraction cord with copy abutments techniques.

Material And Methods: Thirty single posterior metal-ceramic implant-supported restorations were delivered to 20 patients. The crowns were fabricated with occlusal openings obturated with composite, and then luted with resin-reinforced glass-ionomer cement on customised standard abutments. The cementation procedure was performed twice in the same specimens using rubber dam (group 1) and retraction cord with copy abutment (group 2). If no cement remnants were seen on periapical radiographs after cleaning, the crown-abutment unit was dismounted. All quadrants of the specimens were photographed to calculate the percentage proportions of residual cement area. Mann-Whitney and Kruskal-Wallis tests were used for statistical analysis.

Results: In each group, 120 measurements were performed (30 implants, 4 surfaces each). The median percentage ratio with interquartile range (IQR) between the cement remnant area and total specimen area was 1.39% (IQR 0.77%-2.29%) and 0.58% (IQR 0.31%-1.33%) in groups 1 and 2, respectively. Lesser cement remnants were found in group 2 with a statistically significant difference (p < .001). The comparison of the mesial, distal, buccal, and lingual surfaces in each group showed no statistically significant differences between them (group 1, p = .482; group 2, p = .330).

Conclusions: The retraction cord and copy abutment reduced the excess cement more efficiently than the rubber dam did. Notwithstanding, undetected cement remnants were observed with both methods, and neither should be considered reliable in clinical applications.