Introduction: The Collum angle can be defined as a crown root supplementary angle of maxillary central incisors. The aim of the study was to assess the maxillary central incisors' collum angle in a sample of Egyptian patients with different vertical malocclusions using cephalometric radiographs.
Methods: Ninety lateral cephalometric radiographs were collected and divided into three groups, with equal size, according to lateral cephalograms (SN-GoGn angle). Group І: consisted of lateral cephalmetric radiographs of 30 who had the strongest predominance of horizontal growth pattern (SN-GoGn ≤28º), Group ІІ: consisted of lateral cephalmetric radiographs of 30 subjects who had the strongest predominance of vertical growth pattern (SN-GoGn ≥35º). Angular and linear parameters on cephalometric radiograph for each subject were measured to identify the facial growth patterns, and Collum angle was then measured.
Results: mean of collum angle for the maxillary central incisor in horizontal growth pattern sample was 7.8°±2.2° with minimum being 5° and max­imum 14°. The mean values for vertical growth pattern was 2.1°±2.1° with minimum 0° and a maximum 6°. Paired samples t-test comparison revealed that there was a high significant increase in maxillary central incisor collum angle in horizontal growers than in vertical growers, mean difference being 5.7°±1°.
Conclusion: Maxillary central incisor collum angle in horizontal growers is higher than in vertical growers.