Comparative evaluation of allograft particulate bone and cortical bone blocks combined with xenograft bone for labial bone defects in the aesthetic zone: a prospective cohort study.

Purpose: This study aimed to evaluate the osteogenic performance of allograft particulate bone and cortical bone blocks combined with xenograft under bovine pericardium membranes, for treating different degrees of labial bone defects in the aesthetic zone. Materials and methods: Twenty-four patients with bone defects were divided into two groups based on defect severity (Terheyden 1/4 and 2/4 groups). The Terheyden 1/4 group received granular bone grafts alone, while the Terheyden 2/4 group received cortical bone blocks combined with granular bone grafts. Cone beam computed tomography scans were taken preoperatively, immediately postoperatively, and six months postoperatively. Primary outcomes included labial bone formation, alveolar bone formation, bone resorption rate, osteogenic efficiency, and complications. Results: Labial bone thickness in both groups exceeded 2 mm after six months. Labial bone formation at the implant shoulder in the Terheyden 1/4 group was 2.35 ± 2.68 mm, and 2.26 ± 1.66 mm in the Terheyden 2/4 group (p > 0.05). Labila and alveolar bone formation at 2–5 mm below the implant shoulder was significantly greater in the Terheyden 2/4 group (p < 0.05). Alveolar bone resorption and the bone resorption rate at 2–5 mm below the implant shoulder was lower in the Terheyden 2/4 group (p < 0.05). Osteogenic efficiency was 64.43 ± 2.76%, with no significant difference between groups (p > 0.05). No complications were observed. Conclusion: Both treatment approaches achieved satisfactory bone regeneration, but combining cortical bone blocks with granular grafts provided better outcomes for larger defects, with greater bone formation and less resorption. Further research with longer follow-up is required to confirm long-term stability. Trial registration: The study was retrospectively registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn/) with the registration number ChiCTR2300070538 on April 14, 2023. [ABSTRACT FROM AUTHOR]