Division of Materials Science and Engineering, Clinic for Reconstructive Dentistry and Temporomandibular Disorders, University Center for Dental Medicine, Hebelstrasse 3, CH-4056, Basel, Switzerland.
Head Face Med. 2017 Nov 21;13(1):22. doi: 10.1186/s13005-017-0155-z.
Resin composite cements are used in dentistry to bond ceramic restorations to the tooth structure. In the oral cavity these cements are subjected to aging induced by masticatory and thermal stresses. Thermal cycling between 5 and 55 °C simulates the effect of varying temperatures in vitro. Purpose of this study was to compare indirect tensile to compressive strength of different cements before and after thermal cycling. The effect of the curing mode was additionally assessed.
Indirect tensile strength and compressive strength of 7 dual-curing resin composite cements (Multilink Automix, Multilink SpeedCem, RelyX Ultimate, RelyX Unicem 2 Automix, Panavia V5, Panavia SA Plus, Harvard Implant semi-permanent) was measured. The specimens were either autopolymerized or light-cured (n = 10). The mechanical properties were assessed after 24 h water storage at 37 °C and after aging (20,000 thermo cycles) with previous 24 h water storage at 37 °C.
Indirect tensile strength ranged from 5.2 ± 0.8 to 55.3 ± 4.2 MPa, compressive strength from 35.8 ± 1.8 MPa to 343.8 ± 19.6 MPa.
Thermocyclic aging of 20,000 cycles can be considered a suitable method to simulate the degradation of indirect tensile strength but not compressive strength of resin composite cements. The effect of thermocycling and the curing mode on the resin composite cements is material dependent and cannot be generalized.
树脂复合粘接剂用于牙科，将陶瓷修复体粘接至牙体组织。在口腔中，这些粘接剂会受到咀嚼和温度应力引起的老化作用。5 至 55°C 的热循环模拟了体外温度变化的影响。本研究的目的是比较不同粘接剂在热循环前后的间接拉伸强度和抗压强度。此外，还评估了固化模式的影响。
测量了 7 种双固化树脂复合粘接剂（Multilink Automix、Multilink SpeedCem、RelyX Ultimate、RelyX Unicem 2 Automix、Panavia V5、Panavia SA Plus、Harvard Implant semi-permanent）的间接拉伸强度和抗压强度。试件分别进行自聚合或光固化（n=10）。在 37°C 下储存 24 小时水后，以及在 37°C 下储存 24 小时水并进行 20,000 次热循环老化后，评估力学性能。
间接拉伸强度范围为 5.2±0.8 至 55.3±4.2 MPa，抗压强度范围为 35.8±1.8 至 343.8±19.6 MPa。
20,000 次热循环老化可被认为是一种合适的方法，可模拟间接拉伸强度但不能模拟树脂复合粘接剂抗压强度的降解。热循环和固化模式对树脂复合粘接剂的影响是材料依赖性的，不能一概而论。
