4D-computerized visualisation of human craniofacial skeletal growth and ofthe development of the dentition

The understanding of growth and developmental changes can be improved when shapes and changes in size, proportion, and relationships are visualized in 3 dimensions and at different stages. This applies particularly to craniof acial skeletal growth and the development of the dentition. For that purpos e 3D-data were collected from prenatal human heads ranging from 18 up to 27 5 mm CRL and from a collection of macerated fetal and postnatal skulls. Com puter-aided graphical reconstructions were obtained from histological seria l sections of embryonic and early fetal specimens. Proportional changes in the growing skull were recorded by means of radiological and cephalometric evaluation. In addition, computed tomography was applied to fetal and postn atal skulls. Furthermore, the prenatal and postnatal development of the den tition was digitized. To that end 3D-polygone sets of these data were read into a workstation computer and animated by means of the software Soft Imag e (Microsoft). This comprehensive 4D insight into growth facilitates the un derstanding and teaching of normal and abnormal development.