Transition of Mandibular Bone Which was Associated With its Development

Objectives: The morphological alteration of the mandibular of its size and thickness is related to the difference of race, sex and individuality.
We set aim for analyzing and investigating the spatial relationship and its change of the mandibular bone by using CBCT.
Methods: Measure the distance of line from the center of mandibular canal to inside of the lingual cortical bone which is in parallel to the acrylic plate.
Measure the distance of line from the center of mandibular canal to the acrylic plate vertically.
Measure the distance of line which was lined in parallel to the acrylic plate from the center of mandibular canal to inside of the lingual cortical bone.
Measure the distance of line which was lined vertically to the buccal cortical bone from the center of mandibular canal to inside of the lingual cortical bone.
Measure the distance of line which was lined vertically to the lingual cortical bone from the center of mandibular canal to inside of the lingual cortical bone.
Results: Thickness of the buccal cortical bone was about1.266 mm(+-0.489).At one third point between the mandibular foramen to the mental foramen, the distance from the buccal cortical bone to the lingual cortical bone become shorter once, and begin getting longer. The line becomes shorter at two third~third fourth, then ahead to the mental foramen.
Near the mandibular foramen, distance from the line to the inferior margin is long, the line becomes shorter until at one third point between the mandibular foramen to the mental foramen. Thickness of the inferior marginal cortical bone was about1.363 mm(+-0.832), then become thicker to the mental foramen and getting the tooth ages.
The mandibular canal keep the distance at one fifth point between the mandibular foramen to the mental foramen. Thickness of the lingual cortical bone was about1.18 mm(+-0.419), thickness of the mandibular bone on 1A and 1C tends to be thinner.
Conclusions: The mandibular canal starts from the center of the mandibular ramus and running the inner lingual side of the mandibular ramus. In the molar part, the mandibular canal runs in the middle of the mandibular bone, then ahead to the buccal side from the premolar part.
The development of the mandibular foramen and mental foramen vertically appears the general type of the Hellman's dental ages.