PhD candidate, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
Clinical Lecturer, Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Mich.
J Prosthet Dent. 2024 Jan;131(1):56-63. doi: 10.1016/j.prosdent.2021.12.029. Epub 2022 Feb 17.
The accuracy of digital waxing-guided trial restoration protocols that have been implemented with ceramic veneers has not been reported.
The purpose of this in vitro study was to evaluate the accuracy of 3 digital trial restorations fabricated from digital waxing for ceramic veneers.
A uniform 0.3-mm digital waxing added to the facial surface of 30 maxillary central typodont incisors was created in a software program. The trial restorations were fabricated on typodont teeth with autopolymerizing acrylic resin by using a silicone index based on 3-dimensionally printed casts designed from the digital waxing. The 30 maxillary central incisors were divided into 3 groups: the depth cutter (0.5 mm, Komet) (DC) group, the round bur (1.5 mm, Diatech) (RB) group, and the specially designed calibrated depth bur (laser mark of 0.5 mm, Gaofeng) (CD) group. The 3 groups were randomly prepared with a random number table by 2 experienced prosthodontists aiming to produce an even facial clearance of 0.5 mm. The dimensional differences in the standard tessellation language (STL) files between the surfaces of the original teeth, digital waxing, trial restorations, and prepared teeth in the software program were measured and analyzed at the same 9 points on the labial surface. One-way ANOVA with a post hoc test was used to identify significant discrepancies between trial restorations and waxing and differences in the reduction depth of typodont teeth (RDT) and the reduction depth (RD) among the 3 techniques (α=.05). The mean relative differences (MRDs) were calculated to determine the accuracy (%).
The thickness of the trial restorations was significantly greater than that of the digital waxings, with a discrepancy of 0.20 ±0.14 mm, especially at the cervical site. With the use of a trial restoration, the RDTs of the middle (-0.01 ±0.11 mm) and cervical locations (0.09 ±0.20 mm) showed significantly smaller preparation depths than did the other locations. Significant differences in RD were found among the 3 guided techniques (P<.05). Group DC presented the most accurate result of 0.51 ±0.08 mm with an MRD of 2%, whereas the results of 0.57 ±0.10 mm with an MRD of 14% and 0.60 ±0.11 mm with an MRD of 20% were obtained from group RB and group DC, respectively.
The trial restoration was significantly thicker than its corresponding waxing. The DC technique presented the most accurate reduction result among the 3 protocols examined.
尚未报道已经实施陶瓷贴面的数字蜡引导试修复方案的准确性。
本体外研究的目的是评估 3 种从数字蜡制取的陶瓷贴面用数字试修复体的准确性。
在软件程序中创建均匀的 0.3 毫米数字蜡添加到 30 个上颌中切牙的唇面。使用基于三维打印模型的硅橡胶印模制取试修复体，该模型是由数字蜡设计而成。将 30 个上颌中切牙分为 3 组：深度切割器（0.5 毫米，Komet）（DC）组、圆钻（1.5 毫米，Diatech）（RB）组和专门设计的校准深度钻（0.5 毫米激光标记，高丰）（CD）组。由 2 名经验丰富的修复医师使用随机数字表随机制备每组，目的是产生均匀的 0.5 毫米唇面间隙。在软件程序中，在唇面的 9 个相同点测量并分析原始牙齿表面、数字蜡、试修复体和预备牙齿的标准 tessellation language（STL）文件之间的尺寸差异。采用单因素方差分析和事后检验比较试修复体和蜡之间以及不同预备技术（RDT）和预备深度（RD）之间的差异（α=.05）。计算平均相对差异（MRD）以确定准确性（%）。
试修复体的厚度明显大于数字蜡，相差 0.20±0.14 毫米，尤其是在颈部。使用试修复体时，中间（-0.01±0.11 毫米）和颈部位置（0.09±0.20 毫米）的 RDT 预备深度明显小于其他位置。3 种引导技术之间的 RD 差异有统计学意义（P<.05）。DC 组的结果最准确，为 0.51±0.08 毫米，MRD 为 2%，而 RB 组和 DC 组的结果分别为 0.57±0.10 毫米和 0.60±0.11 毫米，MRD 分别为 14%和 20%。
试修复体明显比其对应的蜡厚。在 3 种被检查的方案中，DC 技术呈现出最准确的预备结果。
