Janson Guilherme, Valarelli Fabrício Pinelli, Beltrão Rejane Targino Soares, de Freitas Marcos Roberto, Henriques José Fernando Castanha
Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Am J Orthod Dentofacial Orthop. 2006 Jun;129(6):768-74. doi: 10.1016/j.ajodo.2004.11.031.
Although stability of anterior open-bite extraction and nonextraction treatment has been investigated, results suggesting that extraction treatment is more stable have not been confronted. Therefore, the purpose of this cephalometric study was to compare the long-term stability of anterior open-bite extraction and nonextraction treatment in the permanent dentition.
Group 1 consisted of 21 patients treated without extractions, and group 2 included 31 patients treated with extractions who had orthodontic treatment with fixed appliances. Cephalometric headplates were obtained at pretreatment, posttreatment, and postretention. The groups were compared at these 3 times and during the treatment and posttreatment periods with independent t tests. The number of patients with a clinically significant relapse of the open bite was compared between the groups with chi-square tests.
During treatment, the maxillary incisors had greater retraction amounts, and the mandibular incisors had greater retraction and lingual tipping, and less extrusion in the extraction group. In the posttreatment period, the extraction group demonstrated statistically greater stability of the overbite. However, there was no statistically significant difference in the percentages of patients with clinically significant relapse of the open bite between the groups.
Open-bite extraction treatment has greater stability of the overbite than open-bite nonextraction treatment.
尽管已对前牙开颌拔牙矫治和非拔牙矫治的稳定性进行了研究，但表明拔牙矫治更稳定的结果尚未得到验证。因此，这项头影测量研究的目的是比较恒牙列中前牙开颌拔牙矫治和非拔牙矫治的长期稳定性。
第1组由21例非拔牙矫治的患者组成，第2组包括31例采用固定矫治器进行正畸治疗的拔牙矫治患者。在治疗前、治疗后及保持后获取头影测量片。采用独立t检验在这三个时间点以及治疗期间和治疗后阶段对两组进行比较。采用卡方检验比较两组中出现具有临床意义的开颌复发的患者数量。
在治疗期间，拔牙组上颌切牙的内收量更大，下颌切牙的内收和舌倾程度更大，且伸长较少。在治疗后阶段，拔牙组的覆颌稳定性在统计学上更高。然而，两组中出现具有临床意义的开颌复发的患者百分比在统计学上无显著差异。
前牙开颌拔牙矫治比前牙开颌非拔牙矫治具有更高的覆颌稳定性。
