Background Capsular contracture leads to undesirable outcomes when using breast prostheses. Although implant characteristics and surgical techniques have been studied extensively, the impact of suture materials on capsule formation remains unclear.Objectives The aim of the authors of this study is to evaluate the effects of different suture materials on capsular contracture development in a rat model with silicone implants.Methods The rats were divided into 5 groups. Silicone measuring 1.0 x 1.0 x 0.5 cm was implanted in the thoracodorsal region. The incisions were closed using poly(glycolide-co-lactide), polypropylene, polydioxanone, Glycomer 631, and polyglycolide-co-caprolactone in Groups 1 to 5, respectively. The capsule surrounding the implant was examined in histopathological specimens collected during the 12th week after implantation.Results Capsule thickness varied significantly among groups, with Group 1 exhibiting the highest mean thickness and Group 4 the lowest. Inflammation levels also differed, with Group 3 showing the highest proportion of moderate to severe inflammation, whereas Group 4 primarily exhibited mild inflammation. The type of inflammation varied, with Groups 3, 4, and 5 predominantly showing mixed-type inflammation. The presence of foreign body giant cells was highest in Groups 1 and 2, whereas Group 4 had the lowest. No significant differences were observed in hemosiderin presence, collagen organization, or myofibroblast density.Conclusions In terms of the type and degree of inflammation, presence of foreign body giant cells, and average capsule thickness, Group 4 (Glycomer 631) suture had the best overall performance, and Group 1 (poly(glycolide-co-lactide)) performed the worst. Glycomer 631 sutures may reduce capsular contracture in silicone implant surgeries compared with other suture materials.