基于下颌运动轨迹与虚拟[牙合]架运动参数模拟调[牙合]的对比研究

A comparative study based on the mandibular movement track and the movement parameters of the virtual articulator in simulating occlusal adjustment

目的 比较下颌运动轨迹与虚拟[牙合]架运动参数对下颌后牙单冠和三单位桥修复体的虚拟调[牙合]效果。方法选择22名受试者,获取其口腔扫描及下颌运动数据。在牙科设计软件中分别设计具有0.3 mm咬合高点与[牙合]干扰的4种修复体解剖蜡型:44、46牙单冠和44-46、45-47牙三单位桥,虚拟拔除对应牙位上的天然牙。分别使用下颌运动轨迹(下颌运动轨迹组)与虚拟[牙合]架运动参数(虚拟[牙合]架组)对修复体进行虚拟调[牙合]。测量天然牙与调[牙合]后修复体[牙合]面间的三维偏差均方根,比较2组虚拟调(牙合)方法的差异。结果 在相同修复体下,下颌运动轨迹组的三维偏差均小于虚拟[牙合]架组,差异具有统计学意义(P<0.05)。在相同虚拟调[牙合]方法下,44牙单冠的三维偏差最小,46牙单冠的三维偏差最大,且只有44牙单冠与其他修复体间差异存在统计学意义(P<0.05)。结论 在后牙单冠和三单位桥咬合设计时,使用下颌运动轨迹调[牙合]较基于虚拟[牙合]架运动参数的虚拟调[牙合]能更有效地去除修复体的咬合干扰。

Objective This study aimed to compare the effects of virtual adjustment on occlusal interferences in mandibular posterior single crown and three-unit bridge restorations by using the mandibular movement track and the movement parameters of a virtual articulator.Methods Twenty-two participants were recruited.Digital casts of the maxillary and mandibular arches were obtained using an intraoral scanner,and the jaw registration system was used to record the data of the mandibular movement track and the movement parameters of the articulator.Four kinds of restorations with 0.3 mm occlusal interferences were designed with dental design software.In particular,single crowns were designed for teeth 44 and 46,whereas three-unit bridges were designed for teeth 44-46 and 45-47,and the corresponding natural teeth were virtually extracted.Virtual adjustment of the restorations was performed using two dynamic occlusal recordings,namely,the mandibular movement track and the movement parameters of the virtual articulator.A reverse-engineering software was used to measure the root-mean-square of the three-dimensional deviation of the occlusal surfaces between natural teeth and the adjusted restorations.The differences between the two methods of virtual-occlusion adjustment were compared and analyzed.Results For the same group of restorations,the three-dimensional deviation of the mandibular movement track group were lower than those of the virtual articulator group,and the differences were statistically significant(P<0.05).For the four groups of restorations adjusted by the same method,the threedimensional deviation of the 46-tooth single crown was the largest and the smallest three-dimensional deviation was that of the 44-tooth single crown.Statistical differences existed between the 44-tooth single crown and the other groups(P<0.05).Conclusion For the occlusal design of posterior single crown and three-unit bridge,the mandibular movement track could be a more effective approach to virtual occlusal adjustment than the movement parameters of the virtual articulator.