Platzverhältnisse in der Oberkieferfront während der ersten Wechselphase

5.0. Summary The aim of this investigation was to reveal the origin of the space gain in the anterior dental arch, which is needed for the greater mesio-distal diameter of the permanent incisors in contrast to their smaller predecessors. A three-dimensional picture of the increase of the anterior dental arch segment could be obtained by horizontal measurements on 162 mazerated skulls as well as a vertical analysis of the corresponding X-rays. The skulls originate from infants, juveniles and adults. Age-related means and scatterplots were produced and a correlation analysis was performed. This study offers the following results: 1.The dental arch of the maxillary front segment can be approximated by the arc of a circle. 2.The greatest increase was measured during the period of transition of the primary and the permanent incisors. Width, depth, length and the vertical dimension of the maxilla below the nasal floor in the area of the upper incisors increased for the major part during this period. 3.The increment of the maxillary incisor segment was based on vertical „drift” and on an increase in the angle between the incisors and the nasal floor from the deciduous to the permanent incisors.