Department of Medical Biotechnologies, University of Siena, Siena, Italy.
J Esthet Restor Dent. 2016 Mar;28 Suppl 1:S32-9. doi: 10.1111/jerd.12172. Epub 2015 Nov 17.
Tetragonal zirconia polycrystals (TZP) can be used via CAD/CAM technique as metal replacement for fixed partial dentures. However, its intense white color and high opacity may represent an aesthetic limit. New TZPs with a claimed higher degree of translucency were recently marketed. The aim of the study was to investigate contrast ratio (CR), translucency parameter (TP), flexural strength (σ), Weibull characteristic strength (σ0 ), and Weibull modulus (m) of three "traditional" (IPS e.max Zir-CAD, inCoris ZI, VITA In-Ceram YZ) and two "increased translucency" (inCoris TZI, VITA In-Ceram YZ HT) Y-TZPs.
For flexural strength, ISO 6872:2008 was followed. Bars (N = 40) were cut from pre-sintered blocks. Dense-sintering, finishing, and polishing were performed in order to obtain specimens of 15 × 4 × 1.2 mm. Samples were tested with three-point bending setup in a universal testing machine. For CR and TP, specimens (N = 10) were cut perpendicularly to the long axis from pre-sintered blocks. After the dense-sintering, specimens were finished and polished in order to obtain tiles of 12 × 15 × 1 mm. CR and TP were measured with a spectrophotometer equipped with an integrating sphere.
No significant difference was found regarding flexural strength. A significant difference was found both for CR and TP among tested groups. VITA In-Ceram YZ HT and inCoris TZI showed the higher translucency. The difference was not statistically significant when compared with VITA In-Ceram YZ, and statistically significant when compared with IPS e.max Zir-CAD and inCoris ZI.
The new "augmented translucency" TZPs showed higher translucency and similar flexural strength than "traditional" TZPs.
Monolithic zirconia use is partially restricted due to the zirconia low translucency. The new "augmented translucency" zirconia showed a modest but perceptible increase in translucency and a similar flexural resistance, thus increasing the clinically suitable thickness range with optimized aesthetic and resistance. (J Esthet RestorDent 28:S32-S39, 2016).
四方氧化锆多晶（TZP）可通过 CAD/CAM 技术用作固定局部义齿的金属替代品。然而，其强烈的白色和高不透明度可能是一种美学限制。最近市场上推出了声称具有更高透明度的新型 TZP。本研究的目的是研究三种“传统”（IPS e.max Zir-CAD、inCoris ZI、VITA In-Ceram YZ）和两种“增加透明度”（inCoris TZI、VITA In-Ceram YZ HT）Y-TZP 的对比率（CR）、透光率参数（TP）、抗弯强度（σ）、威布尔特征强度（σ0）和威布尔模量（m）。
抗弯强度按照 ISO 6872:2008 进行。从预烧结块中切割出（N=40）条。为了获得 15×4×1.2mm 的试件，进行了致密烧结、精整和抛光。在万能试验机上用三点弯曲装置对样品进行测试。对于 CR 和 TP，从预烧结块的长轴垂直切割（N=10）个试件。致密烧结后，对试件进行精整和抛光，以获得 12×15×1mm 的薄片。用配备积分球的分光光度计测量 CR 和 TP。
各组间抗弯强度无显著差异。在测试组中，CR 和 TP 均有显著差异。VITA In-Ceram YZ HT 和 inCoris TZI 显示出更高的透光率。与 VITA In-Ceram YZ 相比，差异无统计学意义，与 IPS e.max Zir-CAD 和 inCoris ZI 相比，差异有统计学意义。
新型“增强透光率”TZP 具有比“传统”TZP 更高的透光率和相似的抗弯强度。
由于氧化锆的低透光率，部分限制了整体氧化锆的使用。新型“增强透光率”氧化锆的透光率略有提高，但可察觉，抗弯强度相似，从而增加了临床适用的厚度范围，优化了美观和阻力。
