Cephalometric evaluation of intrusion of maxillary posterior teeth by miniscrews in the treatment of open bite.

INTRODUCTION

The objective of this research was to investigate the effectiveness of orthodontic miniscrews for skeletal anchorage during anterior open bite treatment using cephalometric radiographs.

METHODS

This study sample included 20 patients (mean age, 14.71; standard deviation, 1.77) with an anterior open bite. A total of 250 g of force was applied using elastic chains with anchorage from palatal miniscrew to an occlusal splint covering the posterior maxillary teeth. Cephalograms were obtained at the beginning of the treatment when the appliance was first applied and at the 8-month visit when treatment was completed. Paired t tests were used to identify statistically significant differences between initial and final measurements of skeletal and dental parameters.

RESULTS

A decrease of 2.72 ± 1.90° in the SN-GoGn angle and 3.63 ± 1.87 mm in the anterior height (N-Me) parameter in the cephalometric evaluations indicated a significant improvement of vertically increased facial dimensions, with the intrusion of the maxillary posterior teeth (P <0.05). Anterior rotation of the mandible was determined by a 1.76 ± 1.09° increase in the SNB angle and a 1.86 ± 0.90° decrease in the ANB angle (P <0.05). Reductions in the open bite amount by 5.8 ± 0.90 mm, Mx6-SN by 4.00 ± 1.01 mm, and Mx6-PP by 4.01 ± 1.00 mm were indicative of significant intrusion in the maxillary posterior teeth (P <0.05).

CONCLUSIONS

The present study confirmed that palatal miniscrew and maxillary occlusal splint caused intrusion of the maxillary posterior teeth, a decrease in the anterior open bite, and mandibular advancement, with anterior rotation after the maxillary posterior intrusion. We concluded that the treatment method in our study was appropriate for patients with Class I and mild Class II malocclusions and open bite anomalies.