Histologic study of the bone adjacent to titanium bone screws used for mandibular fracture treatment.
OBJECTIVE
Titanium miniplates have been widely used in mandibular fracture fixation because of their strength and excellent biocompatibility. However, the condition of the bone adjacent to titanium bone screws has not been clarified. This study histologically examined the bone-screw interface in patients treated for mandibular fractures.


METHODS
Specimens were obtained from 14 patients, and the undecalcified sections were stained by the toluidine blue and Levai Laczko methods and examined with light microscopy. The mean ratio of direct contact between the bone and the titanium bone screw surface was also analyzed using a computer-aided image analyzer.


RESULTS
The formation of new bone was observed around the titanium bone screws in all cases. In areas of cortical bone, partial interposition of soft tissues was rarely observed. However, in areas of cancellous bone, partial interposition of soft tissues was seen, and bone resorption between the bone and soft tissues was noted. The mean ratio of direct contact between all 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 tissues around the titanium bone screws, and multinuclear giant cells resembling macrophages were observed near these particles.


CONCLUSIONS
Titanium bone screws used for mandibular fracture fixation develop almost complete contact with new bone. Some metalosis is present.
Hirai
H
H
Department of Oral and Maxillofacial Surgery, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
Okumura
A
A
Goto
M
M
Katsuki
T
T
D000293:Adolescent; D000328:Adult; D016301:Alveolar Bone Loss / Q000209:etiology / Q000473:pathology; D000539:Alveolar Process / Q000473:pathology*; D001863:Bone Screws / Q000009:adverse effects*; D005549:Foreign-Body Reaction / Q000209:etiology / Q000473:pathology; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D015726:Giant Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008337:Mandibular Fractures / Q000601:surgery*; D008875:Middle Aged; D016348:Osseointegration; D014025:Titanium / Q000009:adverse effects*
D014025:Titanium