反复烧结对In-Ceram全瓷冠适合性的影响

Effects of Repeated Firings on the Fit of In-Ceram All-ceramic Crowns

【目的】研究体瓷的反复烧结对In Ceram全瓷冠适合性的影响。【方法】制作In Ceram后牙全瓷冠试件 5 0个。试件分为 5组。对照组为氧化铝底层冠 ,实验组依体瓷烧结次数分为 4组 ,即烧结 3次、5次、7次和 9次。采用片切法 ,用万能工具显微镜测量冠边缘 ,轴壁和牙合面与代型之间的粘固剂厚度。【结果】对照组和实验各组 (烧结 3次、5次、7次和 9次 )冠边缘粘固剂厚度分别为 6 9μm、74μm、6 4μm、6 8μm和 6 5 μm ;各组的平均粘固剂厚度依次为 6 1μm、6 3μm、5 8μm、6 3μm和5 9μm。实验各组与对照组各测量点之间的粘固剂厚度的差异无显著性 ;实验各组与对照组之间的平均粘固剂厚度的差异无显著性。【结论】在实验条件下 ,体瓷的反复烧结对In Ceram全瓷冠的适合性无影响。In Ceram全瓷冠在瓷烧结热循环中的尺寸稳定性较好。

Objective To study the fitting effects of repeated firings of In-Ceram all-ceramic crowns. Methods 50 full crown polymethymethacrylate dies were made. Fifty specimens of In-Ceram all-ceramic crown were fabricated according to the manufacturer's instructions. The specimens were divided into the experimental group and the control group. There were 10 specimens of alumina oxide copings in the control group. The experimental group was subdivided into four groups with 10 specimens for each according to the numbers of dentine porcelain firings. The four groups were fired 3, 5, 7, and 9 times. All of them were cemented on the dies with Fuji I. The specimens were invested with self-cured acrylic resin and then were cut open along a long axis of the dies. The toolmaker's microscope was used to measure the film thickness between the crown and the die. Results The average film thickness at the margin of the crowns of five groups were 69 μm, 74 μm, 64 μm, 68 μm, 65 μm and at the different parts were 61 μm, 63 μm, 58 μm, 63 μm, 59 μm respectively, No significant differences were found in the film thickness at the measuring point between the experimental and the control groups. There were no significant diferences in the average film thickness between the experimental and the control groups. Conclusions In this experiment, repeated firings had no effect on the fit of In-Ceram all-ceramic crowns. There's no dimension change in In-Ceram all-ceramic crowns during the firing cycle.