| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1994: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1993: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Research Abstract |
The purpose of this study was to examine the relationship between mandibular growth and the value of bone mineral density by using computed X-ray densitometry (CXD) method. All of subjects consisted of 199 girls and 68 boys aged from 6 to 19 years at initial stage. The materials used were serial hand bone X-rays taken with an aluminum step-wedge ruler, lateral cephalograms and standing height data. The following annual increments were obtained-Cd-Go, Go-Pog', Cd-Gn from cephalograms, SIGMA GS/D,GSmax, GSmin, MCI,D,d, L from second metacarpal image by using "Bonalyzer" (Teijin Ltd.).
Results were as follows :
1. It indicated that peak velocity of SIGMA GS/D was about 2-year later than that of D,L and standing height, and 1-year around menarche in girls.
2. There were significantly positive correlation coefficients between annual increments of total mandibular length and that of standing height, SIGMA GS/D,D and L during puberty.
3. It showed no correlation between facial type and value of SIGMA GS/D.
4. In girls, it significantly showed negative correlation between annual increment of total mandibular lengh and three parameters (SIGMA GS/D,MCI and L) at initial stage, and in boys, only SIGMA GS/D showed negative correlation during puberty. But both of them, there was no correlation before puberal growth period.
From multiple regression analysis with annual increments of mandible as criterion variable and paraneters of CXD method as predictor variables were applied, it should that multiple correlation coefficients was 0.7-0.9 in late adolescent period in boys.
When multiple regression equation was applied, the error between true annual increments of mandible and predicted value were 0.5-1.0 mm in girls, and 1.0-2.0 mm in boys.
Above all, it indicated that the parameters obtained by CXD method were useful for the evaluation of individual skeletal maturation and mandibular growth potentiality in later adolescent period, especially in boys.
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