나이, 성별, 치아상태에 따라 나타나는 아래턱 뼈두께와 뼈밀도 사이의 상관관계

Abstract

The mandible acts on the mastication, speech, and swallowing and undergoes characteristic changes by gender, age, the effect of the systemic factors like body mass index and the metabolism of hormones and the local factors as the dentition, the function of the masticatory muscles, periodontal disease, the compact bone/spongy bone ratio. The morphometric data which reflect the quality and quantity of the mandible are very important to the surgeon for the mandible. It is very useful clinically to predict the status of the mandible indirectly by other medical examinations. This study was undertaken to clarify the correlations of the mandible and other bones, to predict the thickness and bone mineral density of the mandible. Skulls, the 2nd to 5th cervical vertebrae, the first to 4th lumbar vertebrae, bones of forearm and proximal femurs from 22-embalmed cadavers (13 M/9 F, mean age: 63.09 years) and 61 mandible (32 M/29 F, mean age: 66.72 years) obtained from the collection of the Department of Anatomy and Cell Biology of Hanyang Medical College were analyzed. The bone mineral density was measured by dual energy X-ray absorptiometry. In the mandible, bone mineral densities at angle of the mandible, between molars and premolars, around incisors and the thickness, and the length at the sections through the 1st and the 2nd molars were measured. The data were analysed with SPSS 12.0 program according to age, gender and dentition, to verify the statistical significance and the correlation between the thickness and bone mineral densities. The obtained results were as follows. 1. The bone mineral density in the mandibular areas were variable, but statistically insignificant except incisor area. The bone density of the mandible was highly correlated with the thickness of cortical bones and the highest correlation coefficient was shown in sum of the thickness of buccal and lingual cortical bone (correlation coefficient, r=0.622) 2. The bone mineral density of alveolar ridge of maxilla (r=0.753), around neck of femur (r=0.822), total lumbar vertebrae (r=0.649), total cervical vertebrae (r=0.638) and forearm (r=0.610) were highly correlated with that of mandible. 3. The values of bone mineral density in the mandible decreased with age and the most distinct correlated values was that of angle of mandible (r=-0.510). 4. The values of the bone mineral density of mandible, maxilla, cervical vertebrae, lumbar vertebrae, foream and the thickness of cortical bones at the sections through the molars in the man were greater than those in the woman. The correlation coefficient between the thickness and bone mineral density at the molars were greater in the woman. 5. The bone mineral density of whole mandible, the thickness of lingual and basal cortical bones and the height of alveolar ridge were significantly higher in the specimens with both of the 1st and 2nd mandibular molar teeth. The results of this study represents the significant differences of bone mineral density in the mandible according to age, gender and dentition and also significant correlation between the bone mineral density and the thickness of cortical bone. Therefore, it is possible to predict the bone mineral density and the thickness of cortical bone of the mandible with the measurement of bone mineral density of the neck of fumur which is highly correlated with that of mandible.