Quantification of the dental morphology of orangutans.

Orangutans are believed to have close biological affinities to humans. Teeth being the hardest tissue provide useful information on primate evolution. Furthermore, knowledge of the pulp chamber and root canal morphology is important for dental treatment. A female Bornean orangutan and a Sumatran male orangutan skull were available for this study. Both of their dentitions, comprising 50 teeth, were scanned employing the cone-beam computed tomography for both metrical and nonmetrical analyses. Measurements included tooth and crown length, root length, enamel covered crown height, root canal length (posterior teeth), length of pulpal space (anterior teeth), and root canal width. Nonmetrical parameters included number of canals per root, number of foramina in each root, and root canal morphology according to Vertucci's classification. It was found that the enamel covered crown height was the longest in the upper central incisors although the canine was the longest amongst the anterior teeth. Both the upper premolars were three-rooted while the lower second premolar of the Sumatran orangutan was two-rooted, with two foramina. The mandibular lateral incisors of the Bornean orangutan were longer than the central incisors, a feature similar to humans. In addition, secondary dentine deposition was noticed, a feature consistent with aged humans.

Analysis of Malay Arch Width and Anthropometric Correlations

@#The objectives of the study were to determine the normal dental arch width of Malays, their correlation with the facial framework and the ideal size of orthodontic impression trays that fit the dental arch. Eighteen adult Malays with normal Class I occlusion were evaluated. Arch width was measured on each subject’s dental cast. Direct anthropometric measurements were taken for 8 facial landmarks. Orthodontic impression trays were tried on each subject’s dental cast to determine the best fitting tray. Correlations analysis was made between the arch widths and the best fitting impression trays used and also with various craniofacial anthropometric measurements. The eight measurements from the craniofacial region were compared with the maxillary and mandibular intercanine, interpremolar and intermolar widths. In the maxillary arch, there were significant correlation between the face width and the interpremolar and intermolar widths respectively, while in the mandibular arch, significant correlations were noted between the mandible depth and the interpremolar and intermolar widths respectively. The most common fitting impression tray was size 6 for the upper jaw and size 5 for the lower jaw. There was a significant correlation between the maxillary intercanine width and the size of the impression trays. The significant correlation between upper and lower interpremolar and intermolar widths and the anthropometric measurements of this Malay population may assist in predicting arch expansion to achieve Class 1 occlusion during orthodontic or maxillofacial surgical treatment. The significant correlation between the upper intercanine width and the size of impression tray can be a useful parameter when determining the size of impression tray.