A double-blind randomised clinical trial of two techniques for gingival displacement.

Knowledge about security and the potential damage originated by the gingival displacement techniques has not been described through randomised clinical studies. This crossover, double-blind, randomised clinical trial evaluated clinical and immunological factors related to conventional and cordless gingival displacement (GD) techniques, and patients' perceptions in 12 subjects with the employment of 2 GD techniques: conventional (gingival cord + 25% AlCl3 astringent gel) and cordless (15% AlCl3 astringent-based paste). In each subject, two anterior teeth were treated and a 10-day wash-out period separated the two treatments. Periodontal indices were evaluated before (baseline) and 1 and 10 days after GD. Interleukin 1β, interleukin 6 and tumour necrosis factor α concentrations in gingival crevicular fluid were measured before and 1 day after GD. Subjective parameters (pain, unpleasant taste and stress) were also evaluated. Data were analysed by one-way repeated-measures analysis of variance and Tukey's test (immunological factors), the Friedman test (periodontal parameters) and Fisher's exact or chi-squared test (subjective parameters), with a significance level of 95%. Gingival bleeding index, probing depth and plaque index values did not differ significantly between groups at any timepoint. Neither technique resulted in worse periodontal indices. Both techniques yielded similar results for pain and unpleasant taste, but conventional GD was significantly more stressful than cordless GD for volunteers. Both treatments significantly increased mean concentrations of the three cytokines, with the conventional technique producing the highest cytokine levels. Cordless GD is less stressful for patients and results in lower post-treatment levels of inflammatory cytokines compared with conventional GD.