Morphometry of the Cranial Base in Subjects with Class III Malocclusion

The significance of the cranial base in the development of Class III malocclusion remains uncertain. The purpose of this study was to determine whether the form of the cranial base differs between prepubertal Class I and Class III subjects. Lateral cephalographs of 73 children of European-American descent aged between 5 and 11 years with Class III malocclusion were compared with those of their counterparts with a normal, Class I molar occlusion. The cephalographs were traced, checked, and subdivided into seven age- and sex-matched groups. Average geometries, scaled to an equivalent size, were generated based on 13 craniofacial landmarks by means of Procrustes analysis, and these configurations were statistically tested for equivalence. Bivariate and multivariate analyses utilizing 5 linear and angular measurements were undertaken to corroborate the Procrustes analysis. Graphical analysis, utilizing thin-plate spline and finite element methods, was performed for localization of differences in cranial base morphology. Results indicated that cranial base morphology differed statistically for all age-wise comparisons. Graphical analysis revealed that the greatest differences in morphology occurred in the posterior cranial base region, which generally consisted of horizontal compression, vertical expansion, and size contraction. The sphenoidal region displayed expansion, while the anterior regions showed shearing and local increases in size. It is concluded that the shape of the cranial base differs in subjects with Class III malocclusion compared with the normal Class I configuration, due in part to deficient orthocephalization, or failure of the cranial base to flatten during development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67377/2/10.1177_00220345970760021101.pd

Patterns of body and visceral growth in human prenates with clefts of the lip and palate

Objective: To address the hypothesis that human prenates with birth defects such as clefts of the lip and palate show growth patterns in which body size and visceral growth are aberrant for prenatal age. Methods: Body size and organ weight measurements were derived from a cross-sectional population sample of 167 legally donated human embryos that were representative of key periods in visceral organogenesis and growth, Measurements included those of overall body size (i.e., length and weight) and weights of major organs. Data were analyzed for two comparative (age-matched) groups consisting of 120 typical-for-age “control” and 47 specimens showing the three typical cleft types. Organ weight data for the entire cleft group and for each of the three cleft subgroups were compared with those of the control group. Results: Cleft specimens showed crown-rump body sizes that were within one standard deviation of the control group. Among the entire cleft sample, each of the organ weight values was generally consistent with the organ weights observed for the age-matched control group. When organ weights for the cleft group differed from the controls, with one exception, some organs showed either increased or decreased organ weights. One remarkable exception was with lung weights, which were reduced for each of the prenates across the three cleft types, Among the three cleft groups, fetuses with cleft lip and palate showed the highest percentage of organ weight discrepancies (i.e., smaller than expected) as compared with the group with cleft palate, which showed the lowest. Conclusions: Organ weight aberrancies were observable (whether increased or reduced weights), and such aberrancies were not apparent until approximately 24 weeks (fertilization age)