A CBCT Evaluation of Esthetic Preference Regarding the Perceived Facial Attractiveness of Young Korean Female Adults with a Normal Skeletal Pattern.

The aim of this study was to determine the factors that affect esthetic preference regarding the perceived facial attractiveness of young Korean female adults with a normal skeletal pattern using cone-beam computed tomography (CBCT). After reorienting the CBCT images of 40 young Korean female adults, three-dimensional (3D) measurements were analyzed, and five 3D facial images were digitally constructed. A computer-based questionnaire was used to determine perceived facial attractiveness by scoring from 1 (very unattractive) to 10 (very attractive). Esthetic perception and the most influential facial view and component were examined and compared by orthodontists, general dentists, and laypeople to evaluate facial attractiveness. Compared to the unattractive group, the attractive group had significantly greater values for Pog-NB, L1SI-FH, U lip thickness, L lip-U lip, and Nasolabial angle, along with significantly lower values for U1SI-FH and Cant of U lip; the attractive group also had a more retruded U1MP (p < 0.01), L1MP (p < 0.01), U lip (p < 0.05), and L lip (p < 0.01) relative to N, as well as a more retruded U lip (p < 0.05) and L lip (p <0.001) relative to esthetic lines. Orthodontists and general dentists were more likely to consider the profile view. When evaluating facial attractiveness, orthodontists and laypeople more often focused on the lips and chin. When evaluating facial attractiveness, all evaluators showed a high esthetic preference for retroclination and retrusion of the incisors and lips, but there were some differences in how they perceived facial attractiveness. Therefore, the ultimate perception of facial attractiveness needs to be based on the esthetic perceptions of laypeople.

Biomechanical analysis of the maxillary molar intrusion: A finite element study.

INTRODUCTION: The purpose of this study was to analyze and clarify tooth movement when intruding the maxillary molars using intrusive forces between the maxillary first and second molars. METHODS: A finite element method was used to simulate the long-term orthodontic movement of the maxillary dentition by accumulating the initial displacement of teeth produced by elastic deformation of the periodontal ligament. Intrusive forces of 2 N were applied buccally to the archwire between the maxillary first and second molars. Two different sized transpalatal arches (TPAs) (0.036-in and 0.06-in) and a gradually increased constriction bend and torque toward the posterior teeth were applied to prevent buccal tipping of the posterior teeth when intruding the maxillary posterior teeth. RESULTS: The whole maxillary dentition rotated clockwise as the intrusive force passed posteriorly to the center of resistance. Buccal crown tipping of the maxillary posterior teeth and lingual tipping of the maxillary incisors occurred. Their tipping decreased with a constriction bend and lingual crown torque and when a TPA was applied. CONCLUSIONS: Supplemental procedures such as a constriction bend and lingual crown torque and a TPA could effectively prevent the buccal crown tipping of the maxillary posterior teeth when intruding on them.