Movement of the maxillary central incisors with a lingual fixed appliance

Abstract

We used two-dimensional finite element analysis to compare the mechanical reaction in tissues surrounding the maxillary central incisors for cases where force was applied to the lingual of the teeth and for those in which it was applied to the labial side. Using preoperative and postoperative cephalograms, movements of the maxillary central incisors during orthodontic treatment with lingual fixed appliances were compared to movements with labial fixed appliances during retraction of the maxillary incisors in maxillary bicuspid extraction cases.
Use of the two-dimensional finite element model showed that the maxillary central incisors were depressed bodily when vertical force was applied to the lingual surface of the tooth. The maxillary central incisor inclined labially when vertical force was applied to the labial surface of the tooth. The combination of vertical and horizontal forces inclined the maxillary central incisor lingually when force was applied to the lingual surface of the tooth, and the tooth was inclined labially when force was applied to the labial surface of the tooth. Cephalometric analysis indicated that the maxillary central incisors intruded more during maxillary incisor retraction on treatment with a lingual fixed appliance than they did with a labial fixed appliance. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 23-30.