Soult McKinley D, Lien Wen, Savett Daniel A, Gallardo Francisco F, Vandewalle Kraig S
Gen Dent. 2019 Sep-Oct;67(5):30-34.
Digital dentistry has led to the success of same-day, single-crown delivery. Unlike traditional convection furnaces for fabrication of zirconia materials, which typically require several hours to complete sintering, a dedicated high-speed sintering furnace that reportedly sinters zirconia in minutes is now available. Sintering times may increase or decrease based on the size of the restoration due to a novel interface between the chairside acquisition unit, milling unit, and furnace. The purpose of this study was to compare the flexural properties (strength and modulus), optical parameters (translucency and opalescence), and grain size of a full-contour tetragonal zirconia material after sintering in either a novel high-speed furnace or a conventional zirconia furnace. Rectangular zirconia beams were milled and sintered using the high-speed induction furnace for 26.2 minutes or a conventional convection furnace for 4.3 hours. Flexural strength and modulus were determined by subjecting the beams to a 3-point bending test in a materials testing machine. Translucency and opalescence were calculated using a spectrophotometer, and grain size was determined by using an atomic force microscope. The dedicated high-speed induction furnace sintered the tetragonal zirconia specimens in substantially less time than the conventional convection furnace, with a statistically significant decrease in grain size and no significant difference in strength or optical properties.
数字牙科技术已促成了当日单冠修复的成功。与传统用于制造氧化锆材料的对流炉不同，传统对流炉通常需要数小时才能完成烧结，而现在有一种专用的高速烧结炉，据报道能在数分钟内烧结氧化锆。由于椅旁采集单元、研磨单元和烧结炉之间的新型界面，烧结时间可能会根据修复体的大小而增加或减少。本研究的目的是比较在新型高速炉或传统氧化锆炉中烧结后的全轮廓四方氧化锆材料的弯曲性能（强度和模量）、光学参数（半透明度和乳光）以及晶粒尺寸。使用高速感应炉对矩形氧化锆梁进行研磨和烧结26.2分钟，或使用传统对流炉烧结4.3小时。通过在材料试验机中对梁进行三点弯曲试验来测定弯曲强度和模量。使用分光光度计计算半透明度和乳光，并使用原子力显微镜测定晶粒尺寸。专用高速感应炉烧结四方氧化锆试样的时间比传统对流炉大大缩短，晶粒尺寸有统计学意义的减小，而强度或光学性能无显著差异。
