Comparing Dental Arch Forms Between Israeli and North American Populations

Introduction and Objectives: Identification of the dental arch form of the orthodontic patient is a key aspect for achieving a stable, functional, and esthetic dentition. Failure to customize the preformed archwires with the patient's arch form may increase the probability of relapse and can lead to an unnatural smile. The primary objective of this study was to identify the arch form of the Israeli population of both skeletal normocclusion as well as skeletal malocclusions. Thereafter to clarify morphological differences between Israeli and North American white populations in various malocclusions. Materials and Methods: The sample included 134 Israeli (40 Class I, 61 Class II, and 33 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and 2 proportional measurements were taken. The dental arches were classified into square, ovoid, and tapered forms to determine and compare the frequency distributions between the 2 ethnic groups. Results: The most frequent mandibular arch form of the Israeli group was found to be ovoid as apposed to Tapered in the North American white group. The White population had a statistically significant decreased arch width and increased arch depth compared with the Israeli population. The analysis of the Israeli sample indicates that as the maloclussion shifts from class III trough class I to class II the weight of the arch form tends to shift from Square/Ovoid to Ovoid/Tapered. Conclusions: Our results suggest that when treating Israeli patients, one should expect to use the preformed ovoid arch form orthodontic wires in a significant percentage of patients.