Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany.
Clin Oral Investig. 2017 Jun;21(5):1735-1741. doi: 10.1007/s00784-016-1947-4. Epub 2016 Sep 23.
The objective of the study was to investigate the relationship between pH-neutralization, hydrophilicity, and free hygroscopic expansion stress of self-adhesive resin cements (SARCs) after storage in artificial saliva.
The SARCs RelyX Unicem Automix 2 (RX2, 3 M ESPE), iCEM (iCEM, Heraeus) and Maxcem Elite (MCE, Kerr) were under investigation in this study. Cylinders (height × diameter, 6 × 4mm) were prepared from each material and stored in artificial saliva (7d at 37 °C). Cylinder height was measured at baseline and after 7 days. After storage, the compression modulus was measured to calculate the free hygroscopic expansion stress. For pH-neutralization and hydrophilicity assessment, disks (height × diameter, 1 × 1.5 mm) were prepared, covered with electrolyte, and monitored over 24 h at 37 °C. Hydrophilicity was assessed using the static sessile drop technique at baseline and at different time intervals up to 24 h. Data were analyzed using one-way ANOVA and post hoc Student-Newman-Keuls test (S-N-K, α = 0.05).
After 24 h, RX2 (pH 4.68) had a significantly higher (p < 0.05) pH-value than MCE (pH 4.2) and iCEM (pH 3.23). iCEM showed the significantly highest hydrophilicity (p < 0.05) after 24 h (θ 85.02°), while MCE resulted lower (θ 113.01°) in comparison with RX2 (θ 108.11°). The resulting hygroscopic expansion stress of iCEM (29.15 MPa) was significantly higher (p < 0.05) compared to RX2 (14.5 MPa) and MCE (21.02 MPa).
The material with lowest pH-neutralization capacity displayed higher hydrophilicity after 24 h and higher hygroscopic expansion stress after 7 days compared to those with high pH-neutralization.
Remnant hydrophilicity due to low pH-neutralization of SARCs could lead to cement interface stress build-up and long-term failure of silicate ceramic restorations.
本研究旨在探讨自粘接树脂水门汀（SARCs）在人工唾液中储存后的 pH 值中和、亲水性与自由吸湿膨胀应力之间的关系。
本研究选用 RelyX Unicem Automix 2（RX2，3M ESPE）、iCEM（iCEM，Heraeus）和 Maxcem Elite（MCE， Kerr）三种 SARCs 进行研究。每种材料均制备高度×直径为 6×4mm 的圆柱体，并在人工唾液中储存（37°C 下 7d）。在基线和 7d 时测量圆柱体高度。储存后，测量压缩模量以计算自由吸湿膨胀应力。为评估 pH 值中和和亲水性，制备高度×直径为 1×1.5mm 的圆盘，覆盖电解质，并在 37°C 下监测 24h。亲水性在基线和 24h 内的不同时间间隔使用静态固着液滴技术进行评估。使用单向方差分析和事后 Student-Newman-Keuls 检验（S-N-K，α=0.05）对数据进行分析。
24h 后，RX2（pH 值 4.68）的 pH 值明显高于 MCE（pH 值 4.2）和 iCEM（pH 值 3.23）（p<0.05）。24h 后，iCEM 显示出最高的亲水性（p<0.05）（θ 85.02°），而 MCE 与 RX2（θ 108.11°）相比，亲水性较低（θ 113.01°）。iCEM 的吸湿膨胀应力（29.15MPa）明显高于 RX2（14.5MPa）和 MCE（21.02MPa）（p<0.05）。
与 pH 值中和能力高的材料相比，pH 值中和能力最低的材料在 24h 后表现出更高的亲水性，在 7d 后表现出更高的吸湿膨胀应力。
SARCs 由于 pH 值中和能力低而残留的亲水性可能导致水门汀界面应力的积累和硅酸盐陶瓷修复体的长期失败。
