Almeida-Chetti Verónica A, Macchi Ricardo L, Iglesias María E
Dental Materials Department, School of Dentistry, University of Buenos Aires, Argentina.
Acta Odontol Latinoam. 2014;27(2):72-6. doi: 10.1590/S1852-48342014000200005.
The aim of this study is to assess the effect of additional curing procedures on the flexural strength and modulus of elasticity of indirect and direct composite materials. Twenty-four rectangular prism-shaped 2 mm x 2 mm x 25 mm samples of Belleglass, Premisa (Kerr), Adoro and Heliomolar (Ivoclar Vivadent) were prepared. Each composite was packed in an ad-hoc stainless steel device with a TeflonR instrument. A mylar strip and a glass slab were placed on top to obtain a flat surface. Polymerization was activated for 20 seconds with a halogen unit (Astralis 10, Ivoclar - Vivadent) with soft start regime and an output with a 350 to 1200 mw/cm2 range at four different points according to the diameter of the end of the guide. The specimens obtained were then randomly divided into two different groups: with and without additional treatment. In the group with additional treatment, the samples adorro were submitted to 25 minutes in Lumamat 100 (Ivoclar Vivadent) and the rest to 20 minutes in BelleGlass HP (Kerr). After the curing procedures, all samples were treated with sandpapers of decreasing grain size under water flow, and stored in distilled water for 24 h. Flexural strength was measured according to the ISO 404920 recommendations and elastic modulus was determined following the procedures of ANSI/ADA standard No. 27. Statistical differences were found among the different materials and curing procedures employed (P<0.01). The elastic modulus was significantly higher after the additional curing treatment for all materials except Premisa. Further work is needed to determine the association between the actual monomers present in the matrix and the effect of additional curing processes on the mechanical properties of both direct and indirect composites, and its clinical relevance.
本研究的目的是评估额外固化程序对间接和直接复合材料的弯曲强度及弹性模量的影响。制备了24个尺寸为2毫米×2毫米×25毫米的矩形棱柱形样本，材料分别为Belleglass、Premisa（ Kerr公司）、Adoro和Heliomolar（义获嘉伟瓦登特公司）。每种复合材料都用特氟龙仪器包装在一个特制的不锈钢装置中。在顶部放置一条聚酯薄膜条和一块玻璃板以获得平整表面。使用卤素灯装置（Astralis 10，义获嘉-伟瓦登特公司）在软启动模式下激活聚合反应20秒，根据光导末端直径在四个不同点输出范围为350至1200毫瓦/平方厘米的光。然后将获得的样本随机分为两组：有额外处理组和无额外处理组。在有额外处理的组中，Adoro样本在Lumamat 100（义获嘉伟瓦登特公司）中处理25分钟，其余样本在BelleGlass HP（Kerr公司）中处理20分钟。固化程序完成后，所有样本在水流下用粒度逐渐减小的砂纸进行处理，并在蒸馏水中储存24小时。根据ISO 4049:2:0的建议测量弯曲强度，并按照ANSI/ADA标准第27号的程序测定弹性模量。在所使用的不同材料和固化程序之间发现了统计学差异（P<0.01）。除Premisa外，所有材料在额外固化处理后的弹性模量均显著更高。需要进一步开展工作，以确定基体中实际存在的单体与额外固化过程对直接和间接复合材料力学性能的影响之间的关联及其临床相关性。
