QUANTITATIVE-EVALUATION OF CORRELATION OF SKULL MORPHOLOGY IN FAMILIES IN AN ATTEMPT TO PREDICT GROWTH CHANGE

The purpose of the present study was to obtain quantitative values for human skull structures in a cross-sectional analysis of offspring and their parents. The offspring were classified into three groups accord ing to age. For each of 11 maxillo-facial and nine dento-alveolar stru ctural angular measurements, the mean and SD were calculated for each set of paternal, maternal, midparent and offspring. The standard devia tion unit (SDU) values were calculated from the disparity between the measured value in a given individual, i.e. father, mother, midparent, offspring, and their corresponding group mean value. Three disparity v alues (D.v.), expressed by the difference between the SDU values in ea ch pair (father-offspring, mother-offspring and midparent-offspring), were developed to evaluate the degree of familial resemblance for each of 20 morphometric measurements, and the differences among these valu es in three age groups were then investigated. The similarity ratio (S .r.), expressing the degree of correlation to the father and mother, w as derived by processing the D.v. The relationship between the maxillo -facial S.r. and the dento-alveolar S.r. was analysed in each age grou p. There were significant differences between the D.v. in families and those in unrelated control groups, Consistency between the S.r. for m axillo-facial and that for dento-alveolar measurements was found in th e older age groups. it is concluded that individual growth of skull mo rphology might be more predictable using the present method.