The impact of retraction cords on the gingival margin level: A randomized clinical trial

To examine the impact of placing plain and impregnated retraction cords for two different retraction times on the postoperative gingival margin level and periodontal health.

A total of 40 endodontically treated mandibular first molars were selected and randomly allocated into four groups (n = 10/group); A: plain retraction cord for 10 min, B: plain retraction cord, 20 min, C: impregnated (25% aluminum chloride (AlCl₃) retraction cord, 10 min, D: impregnated retraction cord (25% AlCl₃), 20 min. Intraoral digital scans were acquired, and periodontal parameters (Plaque index [PI], Bleeding on probing [BOP], and probing depth [PD]) were assessed at baseline, 7 days, and 28 days after retraction. The digital scans were superimposed to measure the change in the mid-buccal gingival margin level. Statistical differences between groups at the threetime points were tested using one-way ANOVA and Chi-square tests (α = 0.05).

AlCl₃-impregnated retraction cord for 20 min resulted in a statistically significant change in gingival margin level than limiting its application to 10 min or using plain cords at the three-time points (p < 0.05) with 88 ± 4 µm gingival recession after 28 days. The assessed periodontal parameters only showed a significant difference between groups in BOP after 7 days of retraction (p = 0.0009); however, all parameters returned to normal after 28 days with no significant difference between groups (p > 0.05).

To avoid transient gingival inflammation or permanent gingival recession, no matter how small, the retraction time of AlCl₃-impregnated cords should be limited to no more than 10 min.