Natural head position (NHP) provides the key for meaningful cephalometric analysis because an extracranial reference line is used instead of intracranial reference lines, known to be subject to considerable biological variation in their inclination. Although the principle of natural head position is being recognized in the orthodontic literature, its… (More)
Facial growth of twins by means of proportionate analysis of changes in the location of landmarks within a rectilinear coordinate system (mesh diagram) has been conducted, utilizing cephalometric data on 148 males and 128 females, observed annually from 8 to 16 years of age. Findings show relative consistence of the facial configuration during this 8 year… (More)
Measurement of anterior and medial inclinations of third molars from 10 to 18 years of age in monozygotic twins finds a consistent pattern of uprighting, with high correlations within twin pairs indicative of strong genetic influence.
Associations in the timing of emergence among the permanent teeth of Boston children were obtained from a mixed longitudinal growth study of 414 Caucasian twin pairs examined annually. Correlations were estimated by the method of maximum likelihood for corresponding left-right teeth, upper-lower teeth, and all paired combinations from central incisor to… (More)
Step functions representing median attainment ages of successive counts on numbers of permanent teeth present in the mouth were obtained separately for 12 early-emerging teeth (I1, I2 and M1) and for 16 late-emerging teeth (C, Pm1, Pm2, and M2). Displacement of each step function to best fit of individual tooth counts defined the variation in dental… (More)