Intradental Occlusal Characteristics of the Primary Dentition

Objective: To describe the characteristics of the dental arch dimensions of the primary dentition in Chinese children. Materials: Consisted of 212 study models (caries-free, primary dentition) of Chinese children, comprising 116 males and 96 females. The mean age was 5.2 years. The sample was selected from a larger collection, based on a random sample of 498 males and 449 females. Methods: An image analyzer was used to measure the amount of spacing and crowding, arch width and arch perimeter. The arch length was calculated indirectly. Results: Spaced arches were more frequent than close arches in both the maxilla and the mandible. The arches with only crowding were more common in the mandible than in the maxilla. The most prevalent location of spacing in the mandible was the primate space. Crowding in the incisor area was more prevalent in the maxilla than in the mandible. No crowding was found in the area of posterior teeth in either of the arches. Generally, the amount of spacing was significantly greater in males than in females, whereas the amount of crowding in females was slightly greater than in males. Arch width in both arches was significantly larger in males, whereas the arch length was significantly longer in the mandibular arch only. The arch perimeter in both arches was significantly less in females. Conclusions: Differences in the intradental occlusal characteristics exist between the maxilla and mandible, as well as some sex and ethnic differences