サル頭蓋骨にみられた歯槽骨の Fenestration と Dehiscence

発現頻度・位置・広がり

抄録

A total of 67 (35 maxillae and 32 mandibles) Japanese (M. fuscata) and 74 (37 maxillae and 37 mandibles) crab-eating (M. irus) adult monkey jaws were examined for the incidence and distribution of alveolar bony defects (fenestration and dehiscence) because of the possible etiological factors for such defects.
The following findings were obtained:
1) Over three quarters (M. fuscata 83.3%, M. irus 80.0%) of the maxillary jaws examined showed one or more bony defects, with such defects more common in the maxillae than the mandibles (M. fuscata 33.3%, M. irus 14.3%).
2) Incidence of these bony defects was higher in the posterior region than the anterior region.
3) Fenestrations were more common in the maxillae (M. fuscata 76.7%, M. irus 77.1%) than the mandibles (M. fuscata 18.5%, M. irus 5.7%). The relatively high susceptibility of the maxillary first molars (42.0%, 47.3%) and first premolars (31.0%, 42.9%) to fenestration in Japanese and crab-eating monkeys was found in the present study. There was no difference in number of dehiscences between the maxillary and mandibular jaws. Dehiscences were found most frequently on the maxillary first molars and the mandibular third molars in Japanese monkeys and the mandibular third molars in crab-eating monkeys.
4) Bony defects were predominantly found in the bimaxillary facial plate, with the exception of lingual plate in the maxillary first molars.
5) Occurrence of fenestrations was commonly associated with root apex in the maxillae and coronal root in the mandibles.
6) Examination of the data showed what appeared not to be a correlation between the occlusal wears and the bony defects.
7) A congenital cortical osseous defect, a anatomic difference in the cortical plate density and thickness, a prominent root contour of the involved areas, a malalignment of teeth, a abnormality of buccal frenum attachment, a diet and a simply excessive traumatic force may be entertained as possible etiological factors of the bony defects.