Ultrafast sintering of dental zirconia: composition-processing-property relationships with high-throughput fail-fast screening

项目摘要/摘要 传统的烧结(CS)方案可生产高质量的氧化锆修复体，适用于各种类型的 有迹象表明。然而，CS需要4-10小时的点火周期，这是数字牙科工作流程中的瓶颈，排除了 从主席的申请中得到的氧化锆。采用快速加热的当前速度烧结(SS)协议(高达6C/S) 感应炉可以将烧结时间缩短到0.3-0.5小时。然而，由于对流效率低下 热传递，导致温度不均匀，SS产生具有较高孔隙率的微结构，因此 影响氧化锆半透明性和强度。此外，不均匀的致密化引起了人们对 修复体的化学和尺寸稳定性、内部适合性和边缘适合性。因此，SS在很大程度上是 仅限于由4摩尔%的氧化钇稳定的氧化锆(4YSZ)制成的单一单元冠。因此， 长期目标是大幅提高烧结速度(约60 S)，同时最大限度地利用机械和 新型超滤技术制备牙科氧化锆(超过SS-YSZ和CS-YSZ)的光学性质 技术。这项建议的总体目标是：(1)确定成分和时间-温度- 转型(TTT)关系，指导不同行业和部门的材料选择，具有特殊的 注意牙科用YSZ的强度和半透明性的优化；和(2)演示 与质量和寿命有关的改进的尺寸、长期化学和结构稳定性 相对于SS和CS的UFS-YSZ恢复。中心假设是新的UFS方法论将 极大地提高了数字工作流程的时间效率，同时优化了氧化锆的性能并扩展了 一次就诊治疗的适应症范围。这一假设直接来自初步结果和一个 最先进的材料科学知识库。为了验证这一假设，我们将追求三个具体目标：(1) 用超快烧结技术结合X射线衍射仪表征氧化钇稳定氧化锆料的性能 高通量快速失效筛选；(2)测定抗低温降解和抗疲劳能力 超快烧结氧化锆的断裂与电流速度和常规烧结的关系；以及(3)评价 超快烧结三单元固定牙修复体的尺寸稳定性、内适合性和边缘适合性 相对于电流速度和常规烧结。这种方法是创新的，因为它完全脱离了 从目前的炉膛烧结概念出发，使用焦耳加热元件，具有更有效的辐射和 传导热传递。这项拟议的研究具有重要意义，因为它解决了穷人目前面临的挑战 材料性能与SS和CS较长的烧结时间有关。这样的方法将改善 恢复性手术的效率和准确性提供更多的治疗选择和更好的患者 体验，从而提高生活质量，降低患者的成本。

Project Summary/Abstract Conventional sintering (CS) protocols produce high quality zirconia restorations suitable for a wide range of indications. However, CS requires a firing cycle of 4 – 10 h, a bottleneck in digital dental workflow precluding zirconia from chairside applications. Current speed sintering (SS) protocols using fast heating (up to 6C/s) in an induction furnace can reduce sintering times to 0.3 – 0.5 h. However, because of inefficiency of convective heat transfer, leading to temperature inhomogeneity, SS produces microstructures with higher porosities, thus compromising zirconia translucency and strength. In addition, non-uniform densification raises concerns about chemical and dimensional stability, internal fit and marginal adaptation of restorations. As a result, SS is largely limited to the fabrication of single-unit crowns from 4 mol% yttria stabilized zirconia (4YSZ). Accordingly, the long-term goal is to drastically increase sintering speed (on the order of 60 s) while maximizing mechanical and optical properties of dental zirconia (exceeding those of the SS- and CS-YSZ) by implementing novel UFS technologies. The overall objectives of this proposal are to (1) establish composition and time-temperature- transformation (TTT) relationships to guide material selections for various industries and sectors, with special attention to the optimization of strength and translucency of YSZ for dental applications; and (2) demonstrate improved dimensional, long-term chemical and structural stabilities pertaining to the quality and longevity of UFS-YSZ restorations relative to SS and CS. The central hypothesis is that novel UFS methodology will dramatically increase time efficiency of digital workflow while optimizing zirconia properties and expanding the range of indications for single-visit treatments. This hypothesis follows directly from preliminary results and a state-of-the-art material science knowledge base. To test this hypothesis, we will pursue 3 specific aims: (1) To characterize the properties of yttria stabilized zirconia using ultrafast sintering technology in conjunction with high-throughput fail-fast screening; (2) To determine the resistance to low temperature degradation and fatigue fracture of ultrafast sintered zirconia relative to current speed and conventional sintering; and (3) To evaluate the dimensional stability, internal fit, and marginal adaptation of ultrafast sintered 3-unit fixed dental prostheses relative to current speed and conventional sintering. The approach is innovative because it departs completely from the current furnace-sintering concept by using Joule heating elements with more effective radiation and conduction heat transfer. The proposed research is significant because it addresses current challenges in poor material properties associated with SS and the long sintering time of CS. Such an approach will improve the efficiency and accuracy of restorative procedures to provide more treatment options and better patient experience, thus improving quality of life and reducing cost to the patient.