Graduate Program in Materials Science and Engineering, Federal University of Pelotas, Pelotas, RS, Brazil.
Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
Dent Mater. 2016 Mar;32(3):433-41. doi: 10.1016/j.dental.2015.12.011. Epub 2016 Jan 4.
This study investigated the effect of surface treatment (air-abrasion with alumina or hydrofluoric acid-etching) on feldspar ceramic mechanical strength and initial reliability (24h) before/after adhesive luting.
Ceramic discs (VITA) were tested as monolithic specimens (Acid; Abrasion), luted bilayers (Acid+luting agent; Abrasion+luting agent), or untreated (Control). Luted groups were coated using resin-based agent (RelyX Veneer, 3M ESPE). Biaxial flexural test with ball-on-ring setup was carried out (n=30). Biaxial flexural strength (σbf, MPa), characteristic strength (σ0, MPa), and Weibull modulus (m) were calculated for axial positions z=0 (ceramic surface) and z=-t2 (luting agent surface). For each condition, 95% confidence intervals were calculated. Scanning electron microscopy was used for topography and fractography analyses.
At z=0, σbf and σ0 of luted specimens were higher than of monolithic specimens for both surface treatments. Groups Acid and Abrasion had lower σbf and σ0 than Control. Group Abrasion had poorer mechanical strength. Similar structural reliability was observed for all conditions except for the group Abrasion+luting agent, which had lower m than all other groups. At z=-t2, no significant differences between luted groups were observed for mechanical strength and reliability. A more irregular surface topography with more sharp angles was left by air-abrasion than etching. Monolithic specimens failed from surface pores at the tensile area, whereas failure in luted specimens originated from pores below the resin-ceramic interface.
Air-abrasion yielded lower mechanical strength and initial reliability than acid etching. Presence of a resin-based luting agent layer bonded to ceramic significantly increased its mechanical strength.
本研究旨在探讨表面处理（氧化铝喷砂或氢氟酸蚀刻）对长石陶瓷机械强度的影响，以及在黏结前/后（24 小时）的初始可靠性。
采用单片试件（酸蚀；喷砂）、双层黏结试件（酸蚀+黏结剂；喷砂+黏结剂）和未处理试件（对照组）对陶瓷圆盘（VITA）进行测试。黏结组用树脂基黏结剂（RelyX Veneer，3M ESPE）进行涂层。采用球环装置进行双向弯曲试验（n=30）。计算轴向位置 z=0（陶瓷表面）和 z=-t2（黏结剂表面）处的双向弯曲强度（σbf，MPa）、特征强度（σ0，MPa）和威布尔模数（m）。对于每种情况，计算 95%置信区间。采用扫描电子显微镜进行形貌和断口分析。
在 z=0 处，两种表面处理的黏结试件的 σbf 和 σ0 均高于单片试件。酸蚀组和喷砂组的 σbf 和 σ0 均低于对照组。喷砂组的机械强度较差。除喷砂+黏结剂组外，所有条件下的结构可靠性相似，而该组的 m 低于其他所有组。在 z=-t2 处，黏结组的机械强度和可靠性无显著差异。与蚀刻相比，喷砂处理后表面的形貌更不规则，具有更多的尖锐角度。单片试件在拉伸区域从表面孔隙处失效，而黏结试件的失效源于树脂-陶瓷界面下方的孔隙。
与酸蚀相比，喷砂处理导致机械强度和初始可靠性降低。黏结剂层的存在显著增加了陶瓷的机械强度。
