Li Linlin, Chen Hu, Zhao Yijiao, Wang Yong, Sun Yuchun
Doctoral student, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China.
Attending Doctor, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China.
J Prosthet Dent. 2022 Jul;128(1):33-41. doi: 10.1016/j.prosdent.2020.09.055. Epub 2021 Feb 4.
Existing virtual articulators simulate mandibular movement by using various parameters and are used to design restorations. However, they are not able to reproduce actual patient movements, and the designs of occlusal wear facets by them and by personalized mandibular movement have not been compared.
The purpose of this clinical study was to establish a clinical application protocol for a virtual articulator based on previous research and to evaluate the accuracy of the occlusal wear facets designed by it.
The gypsum casts of 12 participants were scanned with a cast scanner as the original data. A single crown, 3-unit splinted crowns, a 5-unit fixed partial denture, and a fixed complete denture were virtually prepared on the digital mandibular casts by using the Geomagic Studio 2013 software program. High points were created at the wear facets, and corresponding digital wax patterns with occlusal interferences were generated. The exocad software program was used to design corresponding restorations with the copy method. Static (STA restoration) and dynamic (DYN restoration) occlusal adjustments were carried out with the built-in virtual articulator. The mandibular movements of participants were recorded by the novel virtual articulator system, and the occlusal surfaces of the digital wax patterns were adjusted (FUN restoration). The restorations adjusted with the 3 methods were compared with the original data. The mean value and root mean square (RMS) of 3D deviation and positive volumes (V+) in the occlusal direction were measured. Depending on the normality, 1-way ANOVA and the Kruskal-Wallis test were used to analyze the influence of occlusal surface design methods on the morphology of occlusal wear facets (α=.05).
The mean deviation of the 4 kinds of STA restorations ranged from 0.19 mm to 0.22 mm, the DYN restorations from 0.13 mm to 0.17 mm, and the FUN restorations from 0.03 mm to 0.09 mm. A significant difference was found between the STA and FUN restorations of the 3-unit splinted crowns and 5-unit fixed partial dentures (Ρ=.013, Ρ=.021). The mean values of 3D deviation and V+ decreased from the STA group to the DYN group and then to the FUN group. The RMS and V+ were statistically similar (Ρ>.05).
The preliminary results of the study indicate that the FUN 3-unit splinted crowns and 5-unit fixed partial dentures designed with the self-developed virtual articulator were better than the STA restorations. The FUN restorations were more coincident with the morphology of the wear facets on the original teeth.
现有的虚拟牙合架通过使用各种参数来模拟下颌运动，并用于设计修复体。然而，它们无法重现实际患者的运动，并且尚未对通过它们设计的咬合磨损小平面与通过个性化下颌运动设计的咬合磨损小平面进行比较。
本临床研究的目的是基于先前的研究建立一种虚拟牙合架的临床应用方案，并评估由其设计的咬合磨损小平面的准确性。
用石膏模型扫描仪对12名参与者的石膏模型进行扫描，作为原始数据。使用Geomagic Studio 2013软件程序在数字化下颌模型上虚拟制备单冠、3单位联冠、5单位固定局部义齿和固定全口义齿。在磨损小平面处创建高点，并生成具有咬合干扰的相应数字蜡型。使用exocad软件程序通过复制方法设计相应的修复体。使用内置虚拟牙合架进行静态（STA修复体）和动态（DYN修复体）咬合调整。通过新型虚拟牙合架系统记录参与者的下颌运动，并调整数字蜡型的咬合面（FUN修复体）。将用3种方法调整后的修复体与原始数据进行比较。测量咬合方向上三维偏差的平均值和均方根（RMS）以及正体积（V+）。根据正态性，采用单因素方差分析和Kruskal-Wallis检验分析咬合面设计方法对咬合磨损小平面形态的影响（α = 0.05）。
4种STA修复体的平均偏差范围为0.19 mm至0.22 mm，DYN修复体为0.13 mm至0.17 mm，FUN修复体为0.03 mm至0.09 mm。在3单位联冠和5单位固定局部义齿的STA修复体与FUN修复体之间发现有显著差异（Ρ = 0.013，Ρ = 0.021）。三维偏差和V+的平均值从STA组到DYN组再到FUN组逐渐降低。RMS和V+在统计学上相似（Ρ>0.05）。
该研究的初步结果表明，使用自行开发的虚拟牙合架设计的FUN 3单位联冠和5单位固定局部义齿优于STA修复体。FUN修复体与原始牙齿上磨损小平面的形态更吻合。
