祝 静，冉屹东

改良Nance弓配合上颌前方牵引矫治骨性Ⅲ类错的效果

祝 静1，冉屹东2

1 对象与方法

1.2 研究方法

1.2.2 X线片头影测量及模型PAR指数测量 头影测量包括20项软硬组织测量指标，PAR指数测量包括6项测量指标。所有治疗前后X线头颅定位侧位片和模型测量工作由同一工作人员在同一时间段内描图及测量。

1.2.3 数据处理 将21例样本治疗前后头影测量指标及模型测量的PAR指数测量值输入EXCEL文档进行处理。PAR指数各指标测量依照Richmond等[2]的研究结果。

2 结 果

X线头影测量及模型PAR指数测量结果见表1，具体分析如下。

测量项目治疗前治疗后差值颌骨矢状向 SNA(°)77．89±2．3581．26±3．393．37±1．22② SNB(°)80．12±2．4379．96±2．62-0．16±0．23 ANB(°)-2．22±1．491．30±1．143．52±1．57② NA⁃PA(°)-3．15±2．612．54±2．655．69±2．66② Ptm⁃A(mm)38．72±1．3140．87±2．342．15±0．67① ANS⁃Ptm(mm)43．22±2．9144．43±15．221．21±0．61① Wits值(mm)-5．76±2．34-2．02±1．373．74±1．65②颌骨垂直向 ANS⁃ME(mm)54．52±2．1856．13±2．671．61±0．75① ANS⁃NE/N⁃Me(%)51．76±1．5953．03±1．851．27±0．64① Yaxis(°)62．34±3．1264．22±3．281．88±2．05② MP⁃SN(°)30．81±4．3234．75±3．433．94±2．58② FH⁃MP(°)24．34±1．0927．78±1．413．44±1．22②牙齿 U1⁃NA(mm)4．13±1．606．93±1．462．80±1．02① U1⁃SN(°)100．67±6．73105．24±4．814．57±2．13② L1⁃NB(mm)6．23±1．786．01±1．46-0．22±0．78 L1⁃MP(°)88．53±4．2187．71±3．86-0．82±0．68①软组织 UL⁃E(mm)-2．34±1．73-0．86±1．661．48±1．05② LL⁃E(mm)1．99±1．381．46±1．32-0．53±1．04① Z角(°)80．87±3．0975．96±3．87-4．91±2．43② H角(°)8．71±3．6211．57±2．802．86±2．07②PAR指数 牙齿排列(分值)12．79±4．2611．34±2．181．45±1．09 后牙咬合(分值)5．09±3．521．68±0．943．41±8．08① 覆盖(分值)3．69±1．080．53±0．313．16±1．08② 覆(分值)2．45±1．900．62±0．321．83±0．79② 中线(分值)1．45±0．911．27±0．490．18±0．32 加权PAR减少百分率(%)——86．67±12．54①

注：治疗后与治疗前比较，①P<0.05，②P<0.01

2.1 颌骨矢状向变化 改良Nance弓前方牵引矫治后，上颌骨向前生长， SNA、ANB、NA-PA、Ptm-A、ANS-Ptm、Wits值均增大，A点明显前移。

2.2 颌骨垂直向变化 矫治后垂直高度增加，下颌骨向后下旋转，ANS-ME、ANS-NE/N-ME、Y轴角、MP -SN、FH-MP增大。

2.3 上下切牙的变化 矫治后上切牙唇向倾斜，下切牙舌向倾斜， U1-NA、U1-SN增大，L1-MP减小。

2.4 软组织的变化 矫治后上唇突度增大，下唇突度减小，原有软组织侧貌的凹面型得到改善，UL-E和H角增大，LL-E和Z角减小。

2.6 矫治疗程 较小年龄组对矫治力更加敏感，平均疗程较短，6～7岁组平均疗程(5.4±2.0)个月，8～10岁组平均疗程(8.9±2.0)个月。

3 讨 论

3.1 矫治前后X线头影测量结果分析

3.1.1 颌骨改变 本组矫治后SNA、ANB、NA-PA、Ptm-A、ANS-Ptm、Wits值均增加。SNA增加3.37°，说明改良Nance弓前方牵引同样能促进上颌骨向前发育。有学者指出，对年龄较小的儿童不宜应用快速扩弓，以免造成鼻子形态的改变；如果患儿不存在宽度不调，年龄又较小，可以不配合扩弓而直接进行前方牵引[3]。本研究结果表明，改良Nance弓前方牵引没有配合扩弓，同样取得了较好的骨骼效应。SNB减小0.16°，差异无统计学意义，说明下颌突度的减小主要是由于下颌骨发生顺时针旋转所致。

3.1.3 软组织改变 在软组织测量中，UL-E和H角增大，LL-E和Z角减小，上唇显著前移，颏部向后向下移动，Ⅲ类凹面型得到明显改善。

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(2014-02-13收稿 2014-03-20修回)

(责任编辑 梁秋野)

CombinedmodifiedNancearchandmaxillaryprotractionincorrectionofskeletalclassⅢmalocclusion

ZHU Jing1and RAN Yidong2. 1. Department of Stomatology, Ningxia Autonomous Regional Hospital, Chinese People’s Armed Police Forces, Yinchuan 750001, China; 2. Department of Stomatology，the No. 2 Hospital of Baoding, Baoding 071000, China

ObjectiveTo evaluate the dental, skeletal and profile changes in the patients with skeletal class III malocclusion after using maxillary protraction appliance combined with modified Nance arch.Methods21 patients with skeletal class Ⅲ malocclusion in mixed dentition were treated by maxillary protraction combined with modified Nance arch. Cephalometric radiographs and plaster model were analyzed to evaluate skeletodental and profile changes and Peer Assessment Rating (PAR) index before and after treatment.ResultsSNA and ANB angle, NA-PA, Ptm-A, ANS-Ptm, Wits values were increased and subspinale was protracted by 2.15 mm. All of the changes were statistically significant (P<0.05).PAR index indicated that the weighted PAR reduction percentage was 86.67%. The anterior overjet and overbite, posterior occlusion were effectively improved. All the patients’ anterior crossbites were corrected after treatment, but there was no significant change in teeth alignment and midline correction.ConclusionsThe maxillary protraction combined with modified Nance arch are obviously effective for skeletal class III malocclusion in mixed dentition, but posterior occlusion, teeth alignment and midline need to be adjusted with fixed appliance in the further treatment.

skeletal class Ⅲ malocclusion; modified Nance arch; maxillary protraction; cephalometric analysis; PAR index

祝 静，硕士，副主任医师，E-mail: jing88_happy@163.com

1.750001银川，武警宁夏总队医院口腔科； 2.071000,河北省保定市第二医院口腔科

冉屹东，E-mail: ranyidong@126.com

R783.5