Size and forms of the mandibular dental arch in Korean malocclusion patients

Lee, Sung Jun; Baek, Seung Hak; Kim, Sang Cheol; Kook, Yoon Ah

Abstract

The purpose of this study was to clarify morphological differences among mandibular dental arch forms in Korean malocclusion patients. The sample in this study consisted of 114 Class I, 119 Class II, and 135 Class III malocclusion cases. The most facial portions of 13 proximal contact areas were digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on the data of the mandibular tooth thickness. Four linear and two proportional measurements were undertaken. The dental arches were classified into square, ovoid, and tapered forms to compare the frequency distributions. Our results suggested that there was no single arch form specific to any particular Angle classification or sex. It appeared to be the frequency of a particular arch form that varies among the Angle classifications. In comparison of arch measurements between male and female, there was no statistical difference except in the intermolar width. In comparison of arch size measurements among the different Angle classifications, there were statistically significant differences between Class I and Class III malocclusion groups and between Class II and Class III malocclusion groups. In comparison of frequency distribution of arch forms in Class I and III malocclusion groups, the square form demonstrated the highest distribution followed by the ovoid and tapered forms in that order. In the Class II malocclusion group, the square form showed the highest distribution, followed by the tapered and ovoid forms in that order. There was no statistical difference in the frequency distribution of arch forms between male and female groups.