Abstract
Background: Suturing configuration may influence coronal flap positioning during root coverage procedures. This study compared the immediate coronal flap advancement achieved by Butterfly and Sling sutures in a standardized sheep cadaver tunneling model. Methods: This ex vivo randomized paired study included six sheep mandibles providing 12 experimental sites. After tunneling flap preparation and standardization of baseline flap tension to 0.60 N, each site received both Butterfly and Sling sutures in randomized sequence. Coronal flap advancement was measured using a digital caliper. The primary comparison was performed using a paired-samples t-test, with 95% confidence intervals (CIs) and a Hedges-corrected standardized effect size. Period, sequence, and mandible-level sensitivity analyses were also performed. Results: Mean coronal flap advancement was 3.48 ± 0.64 mm with the Butterfly suture and 2.85 ± 0.69 mm with the Sling suture. The Butterfly suture achieved significantly greater advancement, with a mean paired difference of 0.63 mm (95% CI: 0.41–0.85 mm; p < 0.001). The Hedges-corrected standardized effect size was 1.79 (95% CI: 0.86–2.70). No statistically significant period effect was detected (mean difference: −0.08 mm; 95% CI: −0.55 to 0.39 mm; p = 0.719), and the Butterfly–Sling treatment effect did not differ significantly according to application sequence (mean sequence difference: 0.16 mm; 95% CI: −0.37 to 0.68 mm; p = 0.480). In the mandible-level sensitivity analysis, the mean Butterfly–Sling difference remained 0.63 mm (95% CI: 0.38–0.88 mm; p = 0.001). Conclusions: Under controlled ex vivo conditions, the Butterfly suture produced greater immediate coronal flap advancement than the Sling suture. The clinical significance of the 0.63-mm difference remains uncertain and requires investigation in clinical studies.