Upper molar distalization with skeletally anchored TopJet appliance

To retrospectively investigate clinical outcomes with the TopJet appliance. Measurements were taken on dental casts reflecting situations in 15 patients aged 10-48 years before and after orthodontic treatment with a TopJet appliance. Each measurement was taken with a digital caliper and repeated 2 weeks later. Recorded parameters included the amounts of distalization achieved, durations of active treatment to calculate rates of tooth movement, as well as rotational and transversal changes involved in the distalization of upper first molars. Student's t-test was used to compare mean values (alpha=0.05), explorative analysis to distinguish between unilateral and bilateral use of TopJet appliances, and Pearsons's correlation coefficient to determine intraobserver variability. Over a mean treatment duration of 5.9 months, the upper first molars were distalized by 4.0 +/- 2.2 mm, including a mean tooth movement rate of 0.8 +/- 0.6 mm per month. The rotational changes involved in the movements (-1.4 +/- 6.7A degrees) were not statistically significant. Transversal changes were 0.9 +/- 1.2 mm at the level of the mesiobuccal cusps, 1.1 +/- 1.1 mm at the central fossae, and 0.9 +/- 0.9 mm at the distobuccal cusps. All measurements, other than those for rotation (r=0.7), were highly reproducible. Bilateral use of the appliance resulted in greater distalization than unilateral use, the mean difference being 1.4 mm. Bilateral use was more likely to involve inward rotation (+2.0A degrees) on the mesial aspect of the first molars, whereas unilateral use resulted in mild outward rotation (-0.5A degrees). Our results indicate that upper molars can be distalized effectively and efficiently with TopJet appliances. Any degrees of rotation and transversal changes that the first molars undergo during this process do not seem to play a major role.