Comparison of the zygoma anchorage system with cervical headgear in buccal segment distalization.Eur J Orthod. 2009 Aug; 31(4):417-24.EJ
This prospective study aimed to evaluate the effects of the zygoma anchorage system (ZAS) in buccal segment distalization in comparison with cervical headgear (CH). Thirty patients with Class II dental malocclusions were included in the study and were divided into two equal groups: the first group (10 females and 5 males, mean age 14.74 years at T1) received buccal segment distalization with ZAS and the second group (8 females and 7 males, mean age 15.26 years at T1) with CH. The skeletal, dental, and soft tissue changes were measured on cephalograms obtained before (T1) and after (T2) distalization, and these changes were statistically evaluated using a repeated measures analysis of variance, Mann-Whitney U-test, and Wilcoxon test. The Class II buccal segment relationship was corrected to a Class I in an average period of 9.03 +/- 0.62 months in the ZAS group and 9.00 +/- 0.76 months in the CH group. Significant distalization was observed for the posterior teeth in both groups (P < 0.001). Distal tipping of all posterior teeth occurred in the CH group (P < 0.001), but only for the molars in the ZAS group (P < 0.001). The upper incisors retroclined, overjet decreased, and the upper and lower lips retruded in both groups. The ZAS provided absolute anchorage for distalization of the maxillary posterior teeth and can be used as an aesthetic and non-compliant alternative to extraoral traction in the treatment of Class II malocclusions.