Comparison of effectiveness of gingival displacement using retraction cord and aluminum chloride gel.

Background

Gingival displacement is essential during impression making for fixed restorations, as it allows the impression material to flow into the gingival sulcus and accurately record the finish line. This study compared the effectiveness of knitted gingival retraction cord (# 00) and 25% aluminum chloride gel in terms of horizontal gingival displacement, placement time, and bleeding control.

Methods

This randomized controlled trial was conducted at the Department of Prosthodontics, Dow International Dental College, Karachi. Sixty-six patients requiring full-coverage fixed restoration with equigingival margins were enrolled through consecutive sampling and randomly assigned into two equal groups (n = 33). The study was conducted in accordance with the CONSORT guidelines. Group A received gingival displacement using a knitted retraction cord, whereas Group B received 25% aluminum chloride gel. Horizontal gingival displacement was measured on pre- and post-displacement casts using stereomicroscopy. Placement time was recorded in minutes, and bleeding control was assessed clinically. Data analysis was performed using SPSS version 25. Independent-samples t-test and chi-square test were applied, with p ≤ 0.05 considered statistically significant.

Results

The mean horizontal gingival displacement was significantly greater with retraction cord (266.74 ± 32.94 μm) than aluminum chloride gel (180.20 ± 27.64 μm) (p < 0.001). The placement time was significantly shorter for aluminum chloride gel (3.23 ± 0.13 min) than for retraction cord (5.30 ± 0.12 min). Bleeding control was also significantly better in the aluminum chloride gel group than in the retraction cord group (87.9% vs. 66.7%, p = 0.040).

Conclusion

25% aluminum chloride gel provided superior bleeding control and required less placement time, whereas retraction cord produced greater horizontal gingival displacement. Therefore, the choice of gingival displacement system should be guided by the clinical requirements of the procedure. TRIAL REGISTRATION NCT07255976, Initial Release 11/19/2025, Last Release 11/27/2025.