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Introduction: The form and the size of a dental arch are products of the configuration and the naturally established balance of the jaw, alveolar bone, and muscles. We investigated which arch dimensions mostly discriminate particular dentoalveolar classes and sexes., Methods: Plaster dental casts were collected from 137 white adolescent subjects (71 girls, 66 boys) aged between 15 and 18 years (mean, 16.0 ± 1.2 years) with Class I (43 subjects: 24 girls, 19 boys), Class II (50 subjects: 28 girls, 22 boys), and Class III (44 subjects: 19 girls, 25 boys) malocclusions. Casts were scanned with the ATOS II SO (small objects) scanner (GOM mbH, Braunschweig, Germany) and measured with ATOS Viewer software (version 6.0.2; GOM mbH)., Results: The major discriminating factors of the particular dentoalveolar classes are the mandibular canine width/depth ratio and the maxillary molar width/depth ratio, which explain 82.8% of the total variability (P <0.001). Class III subjects with the widest and shallowest frontal segment of the mandibular arch and the posterior segment of maxillary arch are clearly distinguished from Class II subjects whose abovementioned segments are the deepest and narrowest. Class I subjects are more similar to Class II than to Class III subjects. The most homogenous are Class III subjects, with 61.1% of them correctly classified, followed by Class II (57.8%) and Class I (52.4%). Sex differences are significant in linear measurements, but not in ratios., Conclusions: Variability of dental arch dimensions and forms is a common characteristic of all dentoalveolar classes. Maxillary arch form is more distinguishing in the posterior segment, and mandibular arch form is more distinguishing in the anterior segment. Class III patients have the most detectable arch form, and Class I the least detectable arch form., (Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.)

Objective: To test the hypothesis that no differences exist in dental arch dimensions between dentoalveolar Classes I, II, and III, and between male and female subjects, as measured on virtual three-dimensional (3D) models., Materials and Methods: Samples included randomly selected plaster dental casts of 137 white patients (43 Class I, 50 Class II, and 44 Class III) from the Department of Orthodontics, School of Dental Medicine, University of Zagreb, Croatia. Dental models were scanned and digitized using ATOS II SO ("Small Objects") scanning technology (GOM mbH, Braunschweig, Germany). Eight linear and two proportional measurements were calculated for both upper and lower dental arches., Results: In men, a significant difference in the upper dental arch was present in the incisor region, and in the lower dental arch, differences were found in intercanine and intermolar widths (P < .05). Significant differences were noted between male groups in the upper molar depth dimension (P = .022) and in the lower molar and canine depth dimensions (P < .05). Class III males had the greatest lower molar and canine width/depth ratios and the smallest lower canine depth/molar depth ratio. Class III women had wider and shorter mandibular arches when compared with Class I and Class II females., Conclusion: The hypothesis was rejected. The dimensions of the dental arches are related to gender and to dentoalveolar class. Class I and II subjects have similar dimensions of maxillary dental arch, but Class II subjects have a transverse deficit in the mandible. In Class III subjects, the maxillary dental arch is insufficient in transverse and sagittal dimensions, and the mandibular arch dominates in the transverse but not in the sagittal dimension.

The purpose of this study was to investigate dental arch changes that occurred during the mixed dentition in 30 normal occlusion children. Two analyses were done. The first one was at the age of early mixed dentition and the second at the age of late mixed dentition. Most width variables were greater in the males, and depth variables greater in the female subjects. A directionally larger left side of the maxilla and right side of the mandible were observed. Our findings indicate that most arch width dimensions are established in the early mixed dentition. We conclude that the period between the early and late mixed dentition is suitable for environmental factors to disrupt the ideal symmetrical developmental pattern because more growth and developmental changes occur after a relatively stabile period of deciduous dentition.

The study was performed in 30 subjects with class II/1 and 30 subjects with class II/2 anomalies. The aim of the study was to assess the extent to which class II anomalies influenced individual craniometric and gnathometric dimensions as well as to determine whether there were any significant differences between the two subgroups. Craniometric dimensions were measured in each subject by means of standard measuring devices, while gnathometric analysis was carried out on plaster casts of their dental arches. Statistical processing was performed on an IBM PC-AT computer, with a SPSS/PC program support. The study results indicated the maxillomandibular and craniofacial growth to follow a specific pattern as early as in the deciduous dentition in subjects with class II anomalies. Differences between class II subgroups manifested in the range of the following parameters: all transversal craniometric dimensions were greater in class II/2, which was statistically significant in case of Eu-Eu dimension; height of the maxillary part of the face was significantly greater in class II/2; horizontal incisal step was significantly greater in class II/1; although all transversal dimensions of dental arches were considerably greater in class II/2, the differences were not statistically significant; the upper and lower dental arches were longer in class II/1 and II/2, respectively.