A novel approach in treatment of maxillary deficiency by reverse chin cup.

The aim of this study was to evaluate the effectiveness of a newly designed small-sized extraoral appliance on Class III malocclusion and maxillary deficiency in growing patients. The case series included 10 patients (4 males, 6 females) with a mean age of 8.9 +/- 1.72 years who suffered from maxillary deficiency. All the patients were treated with an extra oral appliance which was named as reverse chin cup. This appliance consisted of a high pull cap, a chin cup with two vertical hooks, a removable appliance on the upper jaw, and two elastics which connected the hooks of the cup to the hooks of the removable appliance. The mean treatment time was 24 +/- 9 months. Mean SNA and ANB were significantly increased by 3.1 degrees +/- 1.6 degrees and 3.5 degrees +/- 1.7 degrees, respectively (p<0.001). The level of significance was set at P<0.05. The increase of SNA angle and ANS-PNS distance (p<0.001) and the decrease of nasolabial angle (P<0.004) indicated that the reverse chin cup was effective in moving the maxilla in a forward position. Moreover, the smaller size of this appliance makes it more favorable for patients.