中文摘要：

目的比较单独使用压膜保持器与压膜保持器结合改良Ⅱ型Hawley保持器对前牙深覆牙合矫治后的保持效果。方法选择2011年3月-2013年11月航天中心医院口腔科正畸治疗结束后前牙深覆牙合患者160例,其中青少年（13～20岁）和成人（21～42岁）患者各80例,在正畸治疗结束后,将青少年患者和成人患者分别随机分入A、B组和C、D组,每组40例;A、C组全天戴用压膜保持器（简称压膜组）,B、D组日间戴用压膜保持器、夜间戴用改良Ⅱ型Hawley保持器（简称联合组）。在拆除固定矫治器当天（T1）和戴用保持器的12个月（T2）、24个月（T3）分别检查咬合情况并取模型,拍摄头颅侧位片、上下切牙根尖片及带有咬合印记的上下颌牙合面照片,比较两种保持方式的差异。结果 12个月时牙合创伤程度压膜组均高于联合组[A组（0.33±0.48）vs B组（0.14±0.35）;C组（0.13±0.34）vs D组（0.05±0.23）;P〈0.05];24个月时后牙牙合接触面积比联合组均高于压膜组[A组（3.99±1.32）vs B组（9.83±1.57）;C组（7.31±1.55）vs D组（10.11±0.77）;P〈0.05]。结论联合组在防止前牙创伤牙合及防止后牙咬合接触面积减小方面优于压膜组,更有助于青少年患者牙周健康的保持及后牙的咬合调整。

英文摘要：

Objective To find an appropriate method to effectively maintain the result of correcting deep overbite malocclusions by using vacuum-formed retainers only or combined it with modified HawleyⅡ retainers.Methods Eighty adolescent patients（age ranging from 13-20 years） and eighty adult patients（age ranging from 21-42 years） with deep overbite malocclusions after orthodontic treatment in department of stomatology,Aerospace Central Hospital from March 2011 to November 2013 were included in this study.The two groups were randomly divided into 2 subgroups：group A,B and group C,D,with 40 patients in each group.Patients in group A and C（vacuum-formed retainers group） wore the vacuum-formed retainers day and night,while the patients in group B and D（combination group） wore the vacuum-formed retainers in the day time and modified HawleyⅡ retainers at night.Study models,cephalograms,periapical radiograph and photo of occlusal surface were taken for each patient on the day of debond（T1） and 12（T2）,24（T3） months after debond.The differences between two measurements were compared.Results The ocurrence rate of occlusal trauma in vacuum-formed group was significantly higher than combination group during 12 months retention period [group A（0.33±0.48） vs group B（0.14±0.35）,group C（0.13±0.34） vs group D（0.05±0.23）,P〈0.05].However,the molar occlusion contact area ratio（MOCAR） in combination group was significantly higher than vacuumformed group during 24 months retention period [group A（3.99±1.32） vs group B（9.83±1.57）,group C（7.31±1.55） vs group D（10.11±0.77）,P 0.05].Conclusion Combination group is better than vacuum-formed retainers group in preventing anterior teeth trauma occlusion and reduction of molar contact area,and it can contribute to molar occlusal adjustment and periodontal health for adolescent patients.