Clinical observations on 547 cases of mandibular fractures, with special reference to peculiarities in Hokkaido area

From 1976 to 1984, 547 cases with mandibular fractures were treated in the Department of Oral Surgery, Sapporo Medical College Hospital. These were analysed clinicostatistically and the following results were obtained:1) During this period, the number of cases increased and the most patients came during the summer months which correspon well with other departments of oral surgery.2) Age of patients distributed widely with peak of second and third decades (56.5%). Remarkably more (76.6%) male patients than female.3) The traffic accident cases were very frequent (42.2%), falls in 15.5%, work accidents in 11.9%, athletic injuries in 11.7% and others in 2.4%.4) The majority of mandibular fracture lines were found in so-called “weak” areas of the mandibule, i. e., the region of condyle (25.0%), incisor (18.0%) and mandibular angle (15.8%).5) Regarding the therapy, 380 cases were treated by closed reduction (69.5%), 139 were treated by open reduction and 28 were by alveolarplasty. Recently, the A. O. dynamic compression plate was used in many types of mandibular fractures.