Department of Prosthodontics, Center for Dentistry, Oral Medicine and Maxillofacial Surgery, University Hospital Tuebingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
Department of Medical Materials Science and Technology, Institute of Biomedical Engineering, University Hospital Tuebingen, Osianderstr. 2-8, 72076 Tübingen, Germany.
Dent Mater. 2024 Oct;40(10):1635-1642. doi: 10.1016/j.dental.2024.07.022. Epub 2024 Jul 30.
Conventionally and digitally manufactured removable complete dentures with different dentition forms were examined for manufacturing accuracy (trueness, precision), fracture forces under torsional loading and subsequent repairability.
A total of 90 mandibular prostheses were manufactured. Ten were made using the injection molding technique and finished with prefabricated teeth. 40 bases each, were manufactured subtractively and additively. Digitally the prosthesis' dental arch was divided either into two quadrants or three sextants, or kept as full arch. Afterwards, ten additive and subtractive bases were finished with prefabricated teeth and ten of each with milled quadrants, sextants and full arches. After manufacturing, all specimens were rescanned for accuracy comparisons using the Root Mean Square (RMS). Lastly, all specimens were tested to failure under torsional loading.
Conventionally manufactured dentures showed the greatest deviation in accuracy. The type of base manufacturing did not determine the fracture resistance of the prostheses. The dentition form had a significant influence. While prefabricated teeth (86.01 ± 19.76 N) and quadrants (77.89 ± 9.58 N) showed a low fracture resistance, sextants (139.12 ± 21.41 N) and full arches (141.05 ± 17.14 N) achieved the highest fracture forces. Subtractive bases with prefabricated teeth or quadrants were assessed to be repairable, digital dentures with full arch were assessed as not repairable.
The presented testing set-up is suitable to determine the fracture behavior of dentures rather than of standards. With the possibility of digital design and individual manufacturing, dentures' mechanical stability can be significantly increased, especially with suitable dentition forms.
本研究旨在比较不同牙列形式的传统和数字化制造可摘局部义齿的制造精度（准确性、精密度）、扭转加载下的断裂力和后续可修复性。
共制作 90 件下颌义齿。其中 10 件采用注塑成型技术，用预制牙完成；40 件分别采用减法和加法制造。数字化义齿牙弓分为两部分或三部分，或保持全弓。之后，10 件加法和减法基底用预制牙完成，10 件用铣削的四分之一弓、六分之一弓和全弓完成。制造完成后，使用均方根（RMS）对所有样本进行准确性比较的再扫描。最后，所有样本均在扭转加载下进行失效测试。
传统制造的义齿精度偏差最大。基底制造类型不决定义齿的抗断裂能力。牙列形式有显著影响。预制牙（86.01±19.76 N）和四分之一弓（77.89±9.58 N）的断裂阻力较低，六分之一弓（139.12±21.41 N）和全弓（141.05±17.14 N）的断裂力最高。带预制牙或四分之一弓的减法基底可修复，带全弓的数字化义齿不可修复。
所提出的测试设置适用于确定义齿而不是标准的断裂行为。通过数字化设计和个体化制造，义齿的机械稳定性可以显著提高，特别是采用合适的牙列形式。
