Posttreatment evaluation of the distal jet appliance

This study analyzed molar distalization with the distal jet appliance, its effect on the anchor teeth, and the outcome at the completion of orthodontic treatment. Pretreatment, after distalization, and posttreatment lateral cephalometric radiographs were evaluated for 21 adolescent girls and 12 adolescent boys. The mean age of the subjects at the time of the pretreatment radiograph was 12.8 +/- 2.2 years. The mean time for the correction of the Class II molar relationship was 6.7 +/- 1.7 months, and the mean total treatment time was 25.7 +/- 3.9 months. The results of this study showed that the distal jet appliance distalized the maxillary molars, but there was significant loss of anchorage. The distal jet also showed less tipping of the maxillary molars and better bodily movement of molars because the force was applied closer to the center of resistance. The observations of treatment outcome 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 mandibular first molar. There was no significant increase in lower face height. Consequently the effect on the facial balance was negligible.