Craniofacial characteristics of Caucasian and Afro-Caucasian Brazilian subjects with normal occlusion

OBJECTIVE: The objective of this study was to compare the skeletal, dental and soft tissue characteristics of Caucasian and Afro-Caucasian Brazilian subjects with normal occlusion and to evaluate sexual dimorphism within the groups. MATERIAL AND METHODS: The sample comprised lateral cephalograms of untreated normal occlusion subjects, divided into 2 groups. Group 1 included 40 Caucasian subjects (20 of each sex), with a mean age of 13.02 years; group 2 included 40 Afro-Caucasian subjects (20 of each sex), with a mean age of 13.02 years. Groups 1 and 2 and males and females within each group were compared with t tests. RESULTS: Afro-Caucasian subjects presented greater maxillary protrusion, smaller upper anterior face height and lower posterior face height, larger upper posterior face height, greater maxillary and mandibular dentoalveolar protrusion as well as soft tissue protrusion than Caucasian subjects. The Afro-Caucasian female subjects had less mandibular protrusion and smaller total posterior facial height and upper posterior facial height than males. CONCLUSIONS: Brazilian Afro-Caucasian subjects have greater dentoalveolar and soft tissue protrusion than Brazilian Caucasian subjects, with slight sexual dimorphism in some variables

Three-dimensional ontogenetic shape changes in the human cranium during the fetal period

Knowledge of the pattern of human craniofacial development in the fetal period is important for understanding the mechanisms underlying the emergence of variations in human craniofacial morphology. However, the precise character of the prenatal ontogenetic development of the human cranium has yet to be fully established. This study investigates ontogenetic changes in cranial shape in the fetal period, as exhibited in Japanese fetal specimens housed at Kyoto University. A total of 31 human fetal specimens aged from approximately 8 to 42 weeks of gestation underwent helical computed tomographic scanning, and 68 landmarks were digitized on the internal and external surfaces of the extracted crania. Ontogenetic shape change was then analyzed cross-sectionally and three-dimensionally using a geometric morphometric technique. The results of the present study are generally consistent with previously reported findings. It was found that during the prenatal ontogenetic process, the growth rate of the length of the cranium is greater than that of the width and height, and the growth rate of the length of the posterior cranial base is smaller than that of the anterior cranial base. Furthermore, it was observed that the change in shape of the human viscerocranium is smaller than that of the neurocranium during the fetal period, and that concurrently the basicranium extends by approximately 8° due to the relative elevation of the basilar and lateral parts of occipital bone. These specific growth-related changes are the opposite of those reported for the postnatal period. Our findings therefore indicate that the allometric pattern of the human cranium is not a simple continuous transformation, but changes drastically from before to after birth

Upper Airway Changes After Xbow Appliance Therapy Evaluated With Cone Beam Computed Tomography

Objective: To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients. Materials and Methods: The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 +/- 1.1 years. CBCT images were obtained at the beginning of the treatment (TO) and after the debonding of the Xbow (T1). Results: Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars. Conclusions: Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.Wo