青少年上颌后牙区微种植钉的植入角度研究

目的 通过对不同垂直骨面型患者上颌后牙区的锥形束计算机体层摄影片（CBCT）分析,探讨上颌颊腭向骨质在不同种植植入角度下的厚度,为临床微种植钉植入提供参考.方法 选取60 例Ⅱ类矢状骨面型青少年患者,依照垂直骨面型分为低角、均角和高角三组,进行CBCT 扫描和三维重建.分别测量上颌第二前磨牙与第一磨牙根间区牙槽嵴顶到上颌窦底的高度,并分别测量距离牙槽嵴顶4 mm 处,与相邻牙长轴成90°、60°、45°和30°四个颊侧植入角度的骨质厚度.结果 （1）不同垂直骨面型间,上颌窦底高度的差异有统计学意义（F＝23.66,P ＜ 0.05,低角型最大,高角型最小）;（2）不同垂直骨面型组在相同的植入角度下,骨质厚度的差异有统计学意义,两两比较低角型与高角型间的差异有统计学意义,低角型组大于高角型组（P ＜ 0.05）;（3）同一垂直骨面型组在不同植入角度下,骨质厚度的差异有统计学意义,两两比较45°、30°植入角和90°、60°植入角度间,差异具有统计学意义,90°组、60°组大于45°组、30°组（P ＜ 0.05）.结论 相同植入条件下,Ⅱ类矢状骨面型高角型青少年患者较低角型穿通上颌窦的风险更大.

The study of insertion angle of miniscrew in maxillary posterior area of adolescents

Objective The aim of the research was to study buccal-lingual alveolar bone thickness under different implant insertion angle in post-maxillary area among three kind of vertical facial types by cone-beam computed tomography （CBCT）. Methods Three-dimensional image was reconstructed from CBCT data. Sixty adolescents with Class I1 skeletal pattern were divided into three groups, named as low angle group, average angle group, and high angle group. For each subject, the height of maxillary sinus floor was measured in interradieular spaces between the upper 1st molars and 2nd premolars. The thickness of alveolar bone, 4 mm above the alveolar crest, was measured under different insertion angles （90°, 60°, 45°, 30°）. ANOVA and LSD-t test were performed. Results There was significant difference on the height of maxillary sinus floor among different vertical facial types （F=23.66,P 〈 0.05）. The low angle group showed the largest maxillary sinus height, while the high angle group showed the least. Under the same insertion angle, there was significant difference on bucco-lingual alveolar thickness among different facial types; that of low angle group was larger than that in high angle group. Pairwise comparison showed significant differences between low angle group and high angle group; the thickness of low angle group was larger （P 〈 0.05）. In the same group, bueco-lingual alveolar thickness was statistically significantly different in different insertion angle. Pairwise comparison showed significant differences between 45°, 30°and 90°, 60°; the thickness was larger in 90° and 60° groupsthan that in 45° and 30° groups （P 〈 0.05）. Conclusions The risk of maxillary sinus perforation in high angle group was higher than that in low angle group in the same inserting condition in adolescents with Class II skeletal pattern.