Fan Kuo-Cheng, Lin Yu-Ling, Tsao Hao-Wei, Chen Hsuan, Lee Sheng-Yang, Cheng Yu-Chen, Huang Hsiao-Ping, Lin Wei-Chun
Dental Department, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan.
Department of Dentistry, Wan-Fang Hospital, Taipei Medical University, Taipei 116, Taiwan.
Nanomaterials (Basel). 2022 Jun 25;12(13):2187. doi: 10.3390/nano12132187.
In prosthodontics, the ability of glass-ceramics to express the optical properties of natural teeth is an important goal of esthetic restorations. Dental restorations do not merely need to be similar in color to natural teeth; proper optical properties, such as opalescence, transparency, etc., must be combined in order to achieve excellent esthetic effects. The optical properties of ceramic materials are mainly distinguished by different hues (e.g., A, B, C, and D) combined with translucency (e.g., high translucency (HT), medium translucency (MT), low translucency (LT), and medium opacity (MO)). However, there are many varieties of tooth color. Therefore, it is expected that glass-ceramics can change their nanocrystal size and porosity through different heat-treatment temperatures and times and, thereby, present different transparency effects. This study mainly analyzed the influence of changes in sintering temperature on the optical properties of glass-ceramics. The optical properties of glass-ceramics in the oral cavity were evaluated with human trials. We hypothesized that (1) the transparency of glass-ceramics can be changed by controlling the sintering temperature and (2) glass-ceramics modified by the sintering temperature can be suitable for clinical applications. Results showed that the transparency decreased, the nanoparticle size increased, the crystallinity increased, and the surface hardness decreased as the sintering temperature increased. High-brightness glass-ceramics have more-sensitive optical properties. Results of clinical trials showed that glass-ceramics whose transparency was changed by controlling the sintering temperature can be candidates for clinical applications. Based on the above results, the hypotheses of this study were supported. In the future, we will continue to explore the esthetic field of dental restorations.
在口腔修复学中，玻璃陶瓷展现天然牙齿光学特性的能力是美学修复的一个重要目标。牙齿修复体不仅需要在颜色上与天然牙齿相似；还必须具备适当的光学特性，如乳光、透明度等，才能实现出色的美学效果。陶瓷材料的光学特性主要通过不同的色调（如A、B、C和D）与半透明度（如高半透明度（HT）、中半透明度（MT）、低半透明度（LT）和中不透明度（MO））来区分。然而，牙齿颜色种类繁多。因此，期望玻璃陶瓷能够通过不同的热处理温度和时间改变其纳米晶体尺寸和孔隙率，从而呈现出不同的透明效果。本研究主要分析了烧结温度变化对玻璃陶瓷光学特性的影响。通过人体试验评估了口腔中玻璃陶瓷的光学特性。我们假设：（1）通过控制烧结温度可以改变玻璃陶瓷的透明度；（2）经烧结温度改性的玻璃陶瓷可适用于临床应用。结果表明，随着烧结温度升高，透明度降低，纳米颗粒尺寸增大，结晶度增加，表面硬度降低。高亮度玻璃陶瓷具有更敏感的光学特性。临床试验结果表明，通过控制烧结温度改变透明度的玻璃陶瓷可作为临床应用的候选材料。基于上述结果，本研究的假设得到了支持。未来，我们将继续探索牙齿修复的美学领域。
