Objective:
This study aimed to quantitatively and qualitatively assess anchorage loss of tooth anchorage stabilized by miniscrew (indirect anchor tooth) and to investigate affecting factors of the anchorage loss during adjunctive orthodontic treatment.
Methods:
Indirect anchor tooth (Experimental group, n=52) and untreated tooth (Control group; the 1st and 2nd premolars opposing from the indirect anchor tooth, to which no orthodontic force was applied, n=55) were examined before and after treatments. Dental plaster models before and after treatments were scanned digitally from 28 patients (male, 15; female, 13) treated using the indirect anchor tooth. By superimposing the two models, the amount and the direction of the indirect anchor tooth movement were evaluated using univariate linear mixed model. The possible affecting factors (e.g. treatment duration, the number and location of miniscrew and indirect anchor tooth, etc.) of the indirect anchor tooth movement and its significance were also evaluated using the multiple linear mixed model.
Results:
The indirect anchor tooth moved by 0.9±0.50 mm on average but the indirect anchor tooth did not move significantly greater in a particular transverse, vertical or sagittal direction. The location of the indirect anchor tooth was found to affect the movement and the tooth moved significantly larger in mandible than in maxilla.
Conclusions:
The indirect anchor tooth can move, more in mandible than in maxilla, during adjunctive orthodontic treatment. Therefore, careful monitoring for occlusion changes is required.