利用锥形束CT对不同磨牙关系患者下颌第一磨牙咬合接触情况的研究

Occlusal contacts on the first mandibular molar among patients with different molar relationships using cone-beam CT

摘要:

目的：利用锥形束CT分析不同磨牙关系患者下颌第一磨牙咬合接触情况，并探索该方法的可行性。方法：选取2013年1月至2013年6月于我院放射科就诊需行锥形束CT检查的患者，按照纳入排除标准遴选出347例患者，按照Ⅰ、Ⅱ、Ⅲ类磨牙关系分别记录患者下颌第一磨牙面上近中、中、远中3 部分的A、B、C咬合接触点分布情况，并利用SAS 9.2软件进行统计分析。结果：3 类接触点总数比较，Ⅰ类130例（26.62±10.79）、Ⅱ类131例（26.75±10.81）、Ⅲ类86例（19.16±9.14），差异有统计学意义（H=28.346，P=0.000），组间比较Ⅲ类接触点较其余2 类均少，差异有统计学意义（P<0.016 7）。近中接触点数目比较，Ⅰ类（5.62±3.56）、Ⅱ类（7.96±4.06）、Ⅲ类（4.47±3.61），差异有统计学意义（H=45.045，P=0.000），组间两两比较差异有统计学意义（P<0.016 7）；中部接触点数目比较，Ⅰ类（10.3±4.74）、Ⅱ类（9.24±4.54）、Ⅲ类（6.53±4.04），差异有统计学意义（H=32.390，P=0.000），组间比较Ⅲ类最少，余无统计学差异；远中接触点数目比较，Ⅰ类（10.7±4.89）、Ⅱ类（9.55±5.35）、Ⅲ类（8.16±4.72），差异有统计学意义（H=12.025，P=0.002），其中Ⅲ类数目较Ⅰ类少（P<0.0167），余无统计学差异。A点数目比较，Ⅰ类（10.46±5.75）、Ⅱ类（9.53±5.2）、Ⅲ类（7.83±5.02），差异有统计学意义（H=8.466，P=0.015），组间比较Ⅲ类较Ⅰ类少（P<0.016 7），余无统计学差异；B点数目比较，Ⅰ类（9.66±5.58）、Ⅱ类（10.87±5.08）、Ⅲ类（6.17±4.7），差异有统计学意义（H=39.598，P=0.000），组间比较Ⅲ类数目最少（P<0.016 7），余无统计学差异；C点数目比较，Ⅰ类（6.49±3.46）、Ⅱ类（6.34±4.63）、Ⅲ类（5.16±3.39），差异有统计学意义（H=7.179，P=0.028），组间比较Ⅲ类较Ⅰ类少（P<0.016 7），余无统计学差异。结论：Ⅲ类磨牙关系患者三点式咬合接触点总数、3个部位及B点数目均较其他2类少，牙尖交错位时咬合接触稳定性差；锥形束CT可作为一种新方法分析咬合接触情况。

Abstract:

Objective：To analyze the differences of occlusal contacts on the first mandibular molar among patients with different molar relationships and to discover its practicability. Methods：Patients who needed to take cone-beam CT in our hospital between January 2013 and June 2013 were chosen. Totally 347 patients were selected according to the excluded rules. Numbers of occlusal contacts in the mesiocclusion，middle and distal areas among A，B，C three types of the first mandibular molar were recorded. SAS9.2 was used for statistical analysis. Results：The total number of occlusal contacts among three types was compared：Ⅰtype（n=130，26.62±10.79），Ⅱtype（n=131，26.75±10.81），Ⅲ type（n=86，19.16±9.14），with statistically significant differences（H=28.346，P=0.000）. The number of occlusal contacts was fewer in Ⅲ types than in the other two types，with statistically significant differences（P<0.016 7）. The num－ber of occlusal contacts in the mesiocclusion area among three types was compared：Ⅰtype （5.62±3.56），Ⅱtype（7.96±4.06），Ⅲ type（4.47±3.61），with statistically significant differences（H=45.045，P=0.000）. There were statistically significant differences among groups（P<0.0167）. The number of occlusal contacts in the middle area among three types was compared：Ⅰtype（10.3±4.74），Ⅱtype （9.24±4.54），Ⅲ type （6.53±4.04），with statistically signifi－cant differences（H=32.390，P=0.000）. There were statistically significant differences between groups（P<0.016 7）. The number of occlusal contacts was the fewerest in Ⅲ types and there was no statistically significant difference among groups. The number of occlusal contacts in the distal areas among three types was compared：Ⅰtype（10.7±4.89），Ⅱtype（9.55±5.35），Ⅲ type（8.16±4.72），with statistically significant differences（H=12.025，P=0.002）. The number of occlusal contacts was fewer in Ⅲ types than in Ⅰtype（P<0.016 7） and there was no statistically significant difference among other groups. The number of contact A was compared：Ⅰtype（10.46±5.75），Ⅱtype（9.53±5.2），Ⅲ type（7.83±5.02），with statistically significant differences（H=8.466，P=0.015）. The number of contact A was fewer in Ⅲ type than Ⅰtype（P<0.016 7） and there was no difference among others. The number of contact B was compared：Ⅰtype（9.66±5.58），Ⅱtype（10.87±5.08），Ⅲ type（6.17±4.7），with statistically significant differences（H=39.598，P=0.000）. The number of contact B was the fewest in Ⅲ type（P<0.016 7） and there was no difference among others. The number of contact C was compared：Ⅰtype（6.49±3.46），Ⅱtype（6.34±4.63），Ⅲ type（5.16±3.39），with statistically significant differences（H=7.179，P=0.028）. The number of contact C was fewer in Ⅲ type than Ⅰtype（P<0.016 7） and there was no difference among others. Conclusion：The total occlusal contacts and contact B of type Ⅲ on the first molar are fewer than others，so there is less stability dur－ing the intercuspal occlusion position，and the cone-beam CT could be a new method to research occlusal contacts.