Histologic study of the bone adjacent to titanium bone screws used for mandibular fracture treatment

Purpose: Titanium miniplates have been widely used in mandibular fracture f ixation because of their strength and excellent biscompatibility. However, the condition of the bone adjacent to titanium bone screws has not been cla rified. This study histologically examined the bone-screw interface in pati ents treated for mandibular fractures. Patients and Materials: Specimens were obtained from 14 patients, and the u ndecalcified sections were stained by the toluidine blue and Levai Laczko m ethods and examined with light microscopy. The mean ratio of direct contact between the bone and the titanium bone screw surface was also analyzed usi ng a computer-aided image analyzer. Results: The formation of new bone was observed around the titanium bone sc rews in all cases. In areas of cortical bone, partial interposition of soft tissues was rarely observed. Ho Never, in areas of cancellous bone, partia l interposition of soft tissues was seen, and bone resorption between the b one and soft tissues was noted. The mean ratio of direct contact between al l of the adjacent bone and the surface of the titanium bone screws was 64.4 %. The mean ratio of direct contact between cortical bone and the titanium bone screws was 82.4%. Black particles were observed in the bone and soft t issues around the titanium bone screws, and multinuclear giant cells resemb ling macrophages were observed near these particles. Conclusion: Titanium bone screws used for mandibular fracture fixation deve lop almost complete contact with new bone. Some metalosis is present. (C) 2 001 American Association of Oral and Maxillofacial Surgeons.