不同矢状骨面型错的r角测量

r angle measurement of the different sagittal skeletal pattern

背景:在错畸形的诊断和治疗中,准确地描述颌骨的矢状向关系具有重要的意义。目前的评价方法均存在一定的不足。目的:介绍一种新的头影测量方法r角,以准确反映上下颌骨矢状向关系。方法:对180例13～25岁错畸形青少年患者拍摄头颅侧位片进行头影测量分析,按照4项标准分为3组,确定不同的错畸形类型,分析男女差异。结果与结论:①骨型Ⅰ类错的r值为(40.84±3.10)°,骨型Ⅱ类错的r值为(48.85±3.09)°,骨型Ⅲ类错的r值为(26.12±4.76)°。②各组r值在性别上差异无显著性意义。提示r角能够反映上下颌骨矢状方向不调,具有较好的可重复性。r值在35°～45°之间为骨型Ⅰ类错,小于35°为骨型Ⅲ类错,大于45°为骨型Ⅱ类错。

BACKGROUND：An accurate anteroposterior measurement of jaw relationships is critically important in orthodontic diagnosis and treatment planning.There are some disadvantages in current cephalometric methods.OBJECTIVE：To introduce a new cephalometric measurement,named the r angle,in order to express the sagittal relationship between maxilla and mandible with accuracy and reproducibility.METHODS：One hundred and eighty patients aged 13-25 years were selected to take the pre-treatment cephalometric radiographs.They were divided into skeletal Ⅰ,Ⅱ,and Ⅲ groups on the basis of four standards.The different malocclusion types for the r angle were calculated.Finally,the differences between genders were analyzed.RESULTS AND CONCLUSION：①The r values of skeletal Ⅰ,Ⅱ,and Ⅲ were（40.84±3.10）°,（48.85±3.09）° and（26.12±4.76）° respectively.②There were no statistically significant differences of r value between genders.It indicates that r angle can express the sagittal relationship with good repeatability.r angle between 35 and 45 degrees can be considered to have a Class Ⅰ skeletal pattern.With an angle less than 35 degrees,patients are considered to have a skeletal Class Ⅲ relationship and with an angle greater than 45 degrees,patients have a skeletal Class Ⅱ relationship.