@article{oai:ohu-lib.repo.nii.ac.jp:00002394,
 author = {上岡, 斉 and カミオカ, ヒトシ and KAMIOKA, Hitoshi},
 issue = {2},
 journal = {奥羽大学歯学誌},
 month = {Jun},
 note = {P(論文), To investigate the positional relationship between the maxillo-mandibular deciduous second molars and the successional permanent teeth, the second premolars in the jaw bones, three-dimensional observation of dry skulls was performed using X-ray CT. The specimens were 30 dry skulls, comprising of 15 dry skulls in the deciduous dentition period and 15 dry skulls in the first half of the mixed dentition period. The following results were obtained : 1. Regarding the observation of the horizontally sectioned images, measurement was performed by overlapping horizontally sectioned images of the outline form of the tooth crown of the deciduous second molars, and those of the bony crypt of the second premolars. In the maxillary bone, the bony crypt of the second premolars was mesio-distally within the outline form of the tooth crown of the diciduous second molars, whereas it was bucco-lingually on the palatal side. In the mandibular bone, although the bony crypt of the second premolars was bucco-lingually within the outline form of the tooth crown of the deciduous second molars, it was mesio-distally slightly on the distal side. 2. By observing the position of the central point of the deciduous second molar tooth crown and that of the deciduous second molar tooth root, differences were noted in both the maxilla and mandible, and the distance between the 2 points was larger in the mandible. Furthermore, by observing the position of the central point of the deciduous second molar tooth crown and that of the bony crypt of the second premolars, the distance was larger in the maxilla. 3. Regarding the observation of the vertically sectioned images, bucco-lingual sections of the maxillo-mandibular deciduous second molars were observed. Differences in the inclination angle between the coronal axis of the deciduous second molars and the axis of the bony crypt were smaller in the maxilla than in the mandible. Therefore, it was speculated that the bony crypt was vertically located near the direction of the coronal axis of the deciduous second molars in the maxilla, and was in the inferior position of the crown of the deciduous second molars in the mandible. 4. The vertical distance between the occlusal surface (cuspal mid-point) of the deciduous second molars and the superior edge point of the bony crypt of the second molars was 9.3mm in the maxilla, and 9.8mm in the mandible, and that between the occlusal surface of the deciduous second molars and the central point of the bony crypt was 14.4mm in the maxilla, and 14.0mm in the mandible, showing no significant differences between the maxilla and mandible. Concerning the positional relationship between the maxillo-mandibular deciduous second molars and the second premolars, these findings revealed that the bony crypts of the successional permanent teeth are not positioned in the central area of the deciduous tooth crowns, both bucco-lingually and mesio-distally, but in characteristic positions in both the maxilla and mandible. It was also found that differences in the mutual positional relationship were large in the maxilla, in particular.},
 pages = {67--78},
 title = {乳臼歯とその後継永久歯との位置関係について : X線CTによる第二乳臼歯と第二小臼歯の三次元的観察},
 volume = {32},
 year = {2005}
}