Immuno-histologic and histomorphometric evaluation of *Angelica sinensis* adjunctive to β-tricalcium phosphate in critical-sized class II furcation defects in dogs

Objective: To evaluate the effectiveness of Angelica sinensis (As) adjunctive to β-tricalcium phosphate (β-TCP) bone graft in managing induced critical-sized class II furcation defects in dogs. Materials and Methods: In a randomized design, 24 surgically created defects in the mandibular third and fourth premolars of six dogs were treated with either As granules mixed 1:1 with β-TCP and covered by a collagen membrane (experimental; n=12) or β-TCP alone with collagen membrane (control; n=12). At 4 and 8 weeks, jaw segments were harvested for immunohistologic examination and histomorphometric analysis (height of interradicular bone, percentage bone surface area, and trabecular thickness). Results: Compared to control, the experimental group showed significantly greater interradicular bone height (4 weeks p=0.001; 8 weeks p=0.0001), bone surface area (4 weeks p=0.002; 8 weeks p=0.02), and trabecular thickness (4 weeks p=0.0001; 8 weeks p=0.0001). Alkaline phosphatase immunoreactivity was higher in osteoblasts of the experimental group at both time points. Conclusion: Angelica sinensis enhances periodontal regeneration and bone formation when used adjunctively with β-TCP for furcation defects.