Posttreatment evaluation of the distal jet appliance

This study analyzed molar distalization with the distal let appliance, its effect on the anchor teeth, and the outcome at the completion of orthodonti c treatment. Pretreatment, after distalization, and posttreatment lateral c ephalometric radiographs were evaluated for 21 adolescent girls and 12 adol escent boys. The mean age of the subjects at the time of the pretreatment r adiograph was 12.8 +/- 2.2 years. The mean time for the correction of the C lass II molar relationship was 6.7 +/- 1.7 months, and the mean total treat ment time was 25.7 +/- 3.9 months. The results of this study showed that th e distal jet appliance distalized the maxillary molars, but there was signi ficant loss of anchorage. The distal jet also showed less tipping of the ma xillary molars and better bodily movement of molars because the force was a pplied closer to the center of resistance. The observations of treatment ou tcome indicate that the 1.8-mm mean net anterior movement of the maxillary first molar was more than offset by the 4.8-mm mesial movement of the mandi bular first molar. There was no significant increase in lower face height. Consequently the effect on the facial balance was negligible.