A clinical comparison of cordless and conventional displacement systems regarding clinical performance and impression quality

Statement of problem It is not clear whether newly introduced cordless displacement systems are better able to manage gingiva than conventional systems. Purpose The purpose of this in vivo study was to evaluate the gingival management ability of 4 different displacement methods with a standardized subgingival preparation finish line. Material and methods The effects of 4 displacement techniques on gingival management and impression quality were evaluated by means of 6 evaluation criteria. A subgingival preparation finish line of between 1 and 2 mm was ensured, and the buccal aspects of 252 (n=63) teeth were clinically assessed for ease of application, time spent, bleeding, remnants, and dilatation. The complete reproduction of the preparation finish line and the bubble and void formations on polyether impressions were also evaluated. The data were statistically analyzed with the χ 2 test (α=.05). The Bonferroni correction was used to control Type I error for the pairwise comparison groups (α=.008). Results Statistically significant differences were found for all criteria among the groups ( P P P >.008). The retraction cap with paste group showed better results for ease of application, time spent, and bleeding than the aluminum chloride impregnated cord group ( P P Conclusions Except for the nonimpregnated cord group, all of the groups were comparable and clinically useful, with perfect or acceptable impression qualities.