Elkady Aly Ayman Mohamed, Ameen Shereen Adel, Sami Rasha Nabil
PhD Candidate, Fixed Prosthodontics Department, Cairo University, Cairo, Egypt.
Fixed Prosthodontics Department and Vice Dean for Community Service and Environmental Development, Faculty of Dentistry, Cairo University, Cairo, Egypt.
BDJ Open. 2023 May 10;9(1):19. doi: 10.1038/s41405-023-00146-8.
To measure the required clinical time and volume of occlusal adjustment when the maxillary cast is positioned in a virtual articulator using one of three methods: digitization of a facebow-mounted mechanical articulator (group A), virtual Bonwill triangle (group B) or a 3D face scan (group F).
In this randomized, triple-blind, crossover trial; 11 participants were enrolled. Every participant had one molar indicated for a single crown restoration. Three crowns were designed and milled for every participant molar totaling 33 crowns. Each of the three crowns was fabricated with the participant's casts virtually mounted utilizing a different method. An impression was taken of the crown in place before occlusal adjustment. The occlusal adjustment was then performed and timed with the three crowns in the different groups. After the occlusal adjustment, an impression of the adjusted crown was taken. The pre-adjustment and post-adjustment impressions were digitally superimposed and the volume difference was measured. The Kruskal-Wallis test was used to compare the groups.
Group A showed the shortest mean adjustment time (3:44.59 ± 3:39.07) followed by group F (4:30.09 ± 2:01.50) and group B (4:35.30 ± 2:32.33). The mean adjustment volume for group A was (28 ± 19.1 mm) followed by group F (30.5 ± 18.8 mm) and group B (40.6 ± 29.5 mm). Different virtual mounting methods had no statistically significant effect on adjustment time (P-value = 0.538) or adjustment volume (P-value = 0.490).
A simplified approach in virtual articulator mounting appears to be justified in the construction of a single full-coverage prosthesis. Added labor, time and cost of more elaborate virtual mounting methods seem to be counterproductive.
采用三种方法之一将上颌模型置于虚拟牙合架中，测量所需的临床调牙合时间和调牙合量，这三种方法分别为：面弓固定机械牙合架数字化（A组）、虚拟邦威尔三角法（B组）或三维面部扫描法（F组）。
在这项随机、三盲、交叉试验中，招募了11名参与者。每位参与者有一颗磨牙需进行单冠修复。为每位参与者的磨牙设计并制作了三颗全冠，共计33颗全冠。三颗全冠中的每一颗都使用不同的方法将参与者的模型虚拟安装后制作而成。在调牙合前取就位全冠的印模。然后对不同组的三颗全冠进行调牙合并计时。调牙合后，取调牙合后全冠的印模。将调牙合前和调牙合后的印模进行数字叠加，并测量体积差异。采用Kruskal-Wallis检验对各组进行比较。
A组平均调牙合时间最短（3分44.59秒±3分39.07秒），其次是F组（4分30.09秒±2分01.50秒）和B组（4分35.30秒±2分32.33秒）。A组平均调牙合量为（28±19.1立方毫米），其次是F组（30.5±18.8立方毫米）和B组（40.6±29.5立方毫米）。不同的虚拟安装方法对调牙合时间（P值=0.538）或调牙合量（P值=0.490）无统计学显著影响。
在制作单个全冠修复体时，虚拟牙合架安装的简化方法似乎是合理的。更复杂的虚拟安装方法增加的人力、时间和成本似乎适得其反。
