A clinical study evaluating the efficiency of intrusion in anterior teeth by clear aligner technique

Abstract

Objective The purpose of this clinical study was to evaluate the efficacy of anterior intrusion with clear aligners. Methods The study included 22 patients and 101 anterior teeth (44 maxillary and 57 mandibular) treated with clear aligners. To analyze the clinical efficiency, pre-treatment and post-treatment plaster cast models were laser-scanned and the tooth movements in practice were obtained by digital model superimposition. The results were compared with the amount of tooth movement predicted by clear aligners. Intra-group comparsion were made by a paired t-test. Results The mean accuracy of intrusion with clear aligners was 46.9%. The most accurate intrusion was in mandibular lateral incisors (54.6%), followed by maxillary central incisor (50.9%), and the least accurate tooth was maxillary canines (28.8%). When the teeth were in the process of constriction, the accuracy of intrusion movement would decline and significantly difference(-15.4%, P<0.01)was noted, and the teeth would move as extrusion. Conclusions Overcorrection should be considered in anterior intrusion using aligners, especially in the process of constriction to reduce the possibility of extrusion. Key words: Clear aligners; Model superimposition; Teeth intrusion; Efficiency of teeth movement