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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 max imum 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.

Background Accurate prediction of the mesiodistal widths of canines and premolars in children with primary dentition facilitates interception of malocclusion at an early age. Boston University (BU) approach is one, that is, based on primary teeth for predicting canine and premolar dimensions. Aim The aim was to evaluate the size of unerupted canines and premolars using BU approach in comparison to Tanaka and Johnston (T/J) analysis in a sample of Egyptian children. Materials and Methods A total of 300 children (150 boys and 150 girls) with an average age (7–10) years with existence of primary maxillary and mandibular canines and primary first molars and eruption of all permanent mandibular incisors, free from caries, restoration or any abnormalities in size, shape or structure of teeth. The mesiodistal widths of the required teeth were measured using digital caliper from which widths of permanent canines and premolars were predicted using both T/J analysis and BU approach. Results There was a strong positive correlation between BU approach and T/J analysis when used for children in mixed dentition stage. Conclusion Application of BU approach as a prediction method of permanent teeth dimension in a sample of Egyptian children from Tanta city in the mixed dentition stage revealed a strong correlation with the widely applied T/J analysis.