Biomechanical and histomorphometric characterizations of osseointegration during mini-screw healing in rabbit tibiae

Abstract

Objective: To evaluate effects of different healing times on integration of titanium mini-screws and bones under unloaded conditions. Materials and Methods: Biomechanical stability measurements and histomorphometric observations were performed in a rabbit tibia model after different healing times: 0 (immediate) and 1, 2, 4, and 8 weeks. Results: Biomechanical stability and both maximum torque and maximum pullout load increased with healing time but increased significantly only after 4 weeks. Maximum torque and maximum pullout load both significantly correlated with healing time and with each other. Similarly, histomorphometric analyses showed that new bone formation increased with healing time but increased dramatically only after 4 weeks. The data may provide guidance for determining optimal implant plans in clinical practice. Conclusion: Mini-screw healing is a continuous process, and week 4 is a critical time point in this process. © 2009 by The EH Angle Education and Research Foundation, Inc.