*Marina Rodrigues Santi, DDS, MS, PhD student, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
Rodrigo Barros Esteves Lins, DDS, MS, PhD, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
Oper Dent. 2022 May 1;47(3):346-356. doi: 10.2341/21-015-L.
The purpose of this study was to compare the mechanical properties and push-out bond strength of self-adhesive resin cements (SACs) and a conventional resin cement (CRC).
Eighty bovine incisors were divided into four groups for cementation of a fiberglass post (Whitepost - FGM Dental Group, Coral Springs, FL) with different resin cements: three SACs (Maxcem Elite, MAX - Kerr; Calibra Universal, CAL - Dentsply; and RelyX Unicem 2, RUN - 3M Oral Care) and one CRC (RelyX Ultimate, RXU - 3M Oral Care). The groups were subdivided into two groups each (n=10) for evaluation of the push-out bond strength test (POBS) after 24 hours of water storage or after thermal aging (5000 cycles), following 24 hours of storage. The failure modes were evaluated using a stereomicroscope. Flexural strength (FS) and modulus of elasticity (EM) were determined using a three-point bending. Also, pH of the cements was measured over 48 hours and filler morphology was observed by scanning electron microscopy. Appropriate statistical analyses were performed by SPSS 21.0 (SPSS Inc., Chicago, IL, USA), with a significance level set at 5%. Results: RXU presented the highest POBS at both evaluation times. Among the SACs, RUN and CAL presented significantly lower POBS than MAX in cervical and middle-thirds at the 24-hour evaluation, and in all root regions after thermocycling. Adhesive failure between the cement and dentin were the most prevalent fractures at both times evaluated. MAX presented the lowest FS and RUN showed the highest EM. The pH reached the minimal point at the 30-minute evaluation for RXU and MAX. For RUN and CAL, the minimal pH was observed at the 60-minute evaluation. RXU and RUN presented spherical and regular filler particles, while MAX and CAL presented irregularly shaped and sized filler particles.
The mechanical behavior of SACs is not superior to CRC; however, among all the SACs evaluated, MAX presented the highest POBS and stability after thermocycling evaluation. MAX also reached the closest neutral pH after 48 hours. Therefore, SACs with low initial pH and strong neutralization reactions are recommended, because these characteristics may lead to better mechanical properties and stability.
本研究旨在比较自粘接树脂水门汀（SAC）和传统树脂水门汀（CRC）的机械性能和推出粘结强度。
80 颗牛切牙被分为 4 组，分别用不同的树脂水门汀黏结玻璃纤维桩（Whitepost-FGM Dental Group，Coral Springs，FL）：3 种 SAC（Maxcem Elite，MAX-Kerr；Calibra Universal，CAL-Dentsply；和 RelyX Unicem 2，RUN-3M Oral Care）和 1 种 CRC（RelyX Ultimate，RXU-3M Oral Care）。每组再分为两组（n=10），分别在 24 小时水储存或热老化（5000 次循环）后 24 小时进行推出粘结强度测试（POBS）评估。使用立体显微镜评估失效模式。使用三点弯曲法测定弯曲强度（FS）和弹性模量（EM）。还在 48 小时内测量了水门汀的 pH 值，并通过扫描电子显微镜观察了填料形态。使用 SPSS 21.0（SPSS Inc.，Chicago，IL，USA）进行适当的统计分析，显著水平设定为 5%。结果：在两次评估中，RXU 均表现出最高的 POBS。在 SAC 中，与 MAX 相比，RUN 和 CAL 在 24 小时评估时的颈中和中三分之一处以及热循环后所有根区的 POBS 均显著降低。在两次评估中，粘结剂和牙本质之间的黏附性失效是最常见的骨折类型。MAX 表现出最低的 FS，而 RUN 表现出最高的 EM。RXU 和 MAX 的 pH 值在 30 分钟评估时达到最低值。对于 RUN 和 CAL，最低 pH 值出现在 60 分钟评估时。RXU 和 RUN 呈现出球形和规则的填料颗粒，而 MAX 和 CAL 则呈现出不规则形状和大小的填料颗粒。
SAC 的机械性能并不优于 CRC；然而，在所评估的所有 SAC 中，MAX 在热循环评估后具有最高的 POBS 和稳定性。MAX 在 48 小时后也达到了最接近的中性 pH 值。因此，建议使用初始 pH 值较低且中和反应较强的 SAC，因为这些特性可能会导致更好的机械性能和稳定性。
