替牙期伴功能性旋转前牙反牙合矫治方法的回顾性研究

目的:回顾性评价替牙期伴有下颌功能性旋转前牙反牙合常用矫治方法的有效性及效率。方法:选择2014年1月~2017年9月在常州市口腔医院正畸科诊疗的患者47名:替牙期、牙性或功能性前牙反牙合伴下颌功能性旋转、上牙弓轻度拥挤、非拔牙矫治、可后退至切对切、无系统性疾病史、无明显上下颌骨异常、无口颌面肌功能异常、无口腔不良习惯、知情同意。由同一名高年资医师根据患者的实际情况分别采用活动/固定或功能矫治器进行治疗:活动组1采用带双曲舌簧的牙合垫式矫治器配合前方牵引,活动组2仅采用带双曲舌簧的牙合垫式矫治器,固定组采用2*4矫治技术配合下颌牙合垫去除咬合干扰,功能组采用FRIII配合肌功能训练,记录治疗成功率、矫治周期、复诊次数、矫治费用等,并进行对比分析。结果:除了自行终止治疗者,所有前牙反牙合均得到了纠正。活动组2复诊间隔时间短,矫治周期也最短(P<0.01);而复诊次数各组间无差别(P>0.05);矫治费用活动组2低于活动组1和固定组(P<0.05)。固定组在纠正反牙合的过程中排齐并关闭前牙散在间隙,患者及家长对治疗结果更加满意,这是活动及功能矫治无法比拟的;而固定矫治过程中对口腔卫生要求更高,牙面常发生脱钙,且矫治结束后需制作仅包裹四颗上切牙的压膜保持器,这又是固定矫治不利的一面。结论:伴有下颌功能性旋转的替牙期前牙反牙合在患者良好的配合下通过一个较短时间的矫治均可以得到纠正。

Influence of Setting Condition on Characteristics of Savonius Hydraulic Turbine with a Shield Plate

The aim of this investigation was to improve power performance of Savonius hydraulic turbine utilizing small stream for electric generation.An attempt was made to increase the power coefficient of runner by the use of flat shield plate placed upstream of the runner.The difference of the power coefficient is discussed in relation to clearance between the runner and the bottom wall and the rotation direction of the runner.The flow field around the runner was also examined visually to clarify influences of setting conditions on the power performance.From this study it was found that the power coefficient is achieved for 0.47 by only using a flat shield plate,the increase is up to 80% over the runner without the plate.Moreover,it is the proper condition that clearance ratio is 0.73 in this study.