Assistant Professor and Director, Biomaterials and Biomimetics Research, Department of Operative Dentistry, University of North Carolina School of Dentistry, Chapel Hill, NC.
Postgraduate student, Department of Operative Dentistry, University of North Carolina School of Dentistry, Chapel Hill, NC.
J Prosthet Dent. 2018 Jun;119(6):1007-1013. doi: 10.1016/j.prosdent.2017.06.010. Epub 2017 Sep 28.
Resin-based cements are frequently used in clinical practice. To reduce time and technique sensitivity, manufacturers have introduced the same brand of cement with different dispensing methods. The effect of this change on properties of the cement is unknown.
The purpose of this in vitro study was to evaluate the mechanical properties of resin-based cements with different dispensing systems.
Specimens of resin-based cements (n=14) PANAVIA SA Cement Plus Handmix, PANAVIA SA Cement Plus Automix, RelyX Unicem Handmix, RelyX Unicem 2 Automix, G-CEM Capsule Automix, G-CEM LinkAce Automix, Variolink II Handmix, and Variolink Esthetic Automix were prepared for each mechanical test. They were examined after thermocycling (n=7/subgroup) for 20000 cycles as to fracture toughness (FT) (ISO standard 6872; single-edge V-notched beam method), compressive strength (CS) (ISO 9917-1), and diametral tensile strength (DTS). The specimens were mounted and loaded at a crosshead rate of 1 mm/min (0.5 mm/min for FT) with a universal testing machine until failure occurred. The 2-and 1-way ANOVA followed by the Tukey HSD post hoc test were used to analyze data for statistical significance (α=05).
Thermocycling had a significant effect in reducing the FT property of all resin-based cements except RelyX Unicem 2 and G-CEM LinkAce (P<.05). Variolink II and G-CEM LinkAce showed better FT properties than their automixed counterparts (P<.05). The overall CS of all automixed resin-based cements was better than that of their hand-mixed counterpart, except for Variolink II. PANAVIA SA Automixed and G-CEM LinkAce had higher DTS than their hand-mixed counterparts (P<.05).
Changing the dispensing method alters the mechanical properties of resin-based cements. The clinical significance of these results is yet to be determined.
树脂基水泥在临床实践中经常使用。为了减少时间和技术敏感性，制造商推出了同一品牌的不同分配方法的水泥。这种变化对水泥性能的影响尚不清楚。
本体外研究的目的是评估不同分配系统的树脂基水泥的机械性能。
为每种机械测试制备了树脂基水泥（n=14）的试件，包括 PANAVIA SA 水泥 Plus 手混、PANAVIA SA 水泥 Plus 自动混、RelyX Unicem 手混、RelyX Unicem 2 自动混、G-CEM 胶囊自动混、G-CEM LinkAce 自动混、Variolink II 手混和 Variolink Esthetic Automix。在经过 20000 次热循环后（n=7/亚组），对其进行断裂韧性（FT）（ISO 标准 6872；单边 V 型缺口梁法）、抗压强度（CS）（ISO 9917-1）和直径拉伸强度（DTS）的检测。将试件安装在万能试验机上，以 1mm/min 的十字头速率（FT 为 0.5mm/min）加载，直至试件失效。采用 2 路和 1 路方差分析，然后进行 Tukey HSD 事后检验，以分析数据的统计学意义（α=0.05）。
热循环显著降低了除 RelyX Unicem 2 和 G-CEM LinkAce 之外的所有树脂基水泥的 FT 性能（P<.05）。Variolink II 和 G-CEM LinkAce 的 FT 性能优于其自动混合的同类产品（P<.05）。除了 Variolink II 之外，所有自动混合的树脂基水泥的整体 CS 均优于其手动混合的同类产品。PANAVIA SA 自动混合和 G-CEM LinkAce 的 DTS 高于其手动混合的同类产品（P<.05）。
改变分配方法会改变树脂基水泥的机械性能。这些结果的临床意义尚待确定。
