Ultrasonic Inspection of Composite Resin Restorative Materials
Ultrasonic Inspection of Composite Resin Restorative Materials
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复合树脂修复材料的超声波检测
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发表时间：
2014
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通讯作者：
Mirham A. Y. Barakat
中科院分区：
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作者：
Mirham A. Y. Barakat
修复材料，如人工心脏瓣膜、人工构件、人工晶状体等，被视为植入正常材料中的异常材料。无损超声波工具可以表征各种材料。因此，超声波技术可用于表征修复材料。表征植入修复材料非常重要，因为这些材料容易受到各种变化的影响，例如内部裂纹、表面或深层腐蚀等。这些变化会影响植入修复材料的工作效率。超声波脉冲回波技术用于表征牙科复合树脂样品中的各种不连续性，这些不连续性容易受到不同拉伸应力（50、100、150、200、250、300 mm/min 十字头速度）的影响。研究表明，100 毫米/分钟的十字头速度是牙科修复材料中引发裂纹的临界载荷。否则，在300毫米/分钟的夹头速度下，材料就会破裂，因此可以说该牙科修复材料可以承受低于300毫米/分钟的夹头速度的拉伸应力。索引术语-修复材料、无损超声波工具、裂纹、复合树脂、十字头速度、拉伸应力。简介 复合树脂填充物（白色填充物）是玻璃粉和塑料树脂的混合物，它可以模仿天然牙齿的外观。它们在外观上优于汞合金填充物，但它们比汞合金填充物更昂贵。牙科复合树脂是合成树脂的一种。它们不溶、美观、对脱水不敏感并且易于操作。复合树脂通常由 Bis-GMA 单体、二氧化硅等填充材料以及某些应用中的光引发剂组成。可以添加二甲基乙二肟以实现流动能力。每种成分的独特浓度可实现最佳的物理特性。与汞合金不同的是，汞合金本质上只是填充一个洞，并需要保留功能来固定填充物，而复合空洞修复体在与牙本质和牙釉质粘合技术一起使用时，可以将牙齿恢复到接近其原始的物理完整性。然而，汞合金的失效寿命较长，但美观性较差[1]。复合树脂是重要的工业产品。因此，它被视为一个感兴趣的研究范围。复合树脂在植入时容易受到多种条件的影响，因此可以成为各种不连续性的合适位置。这些不连续性对复合树脂的寿命有严重影响。最常见的不连续性是大多数复合材料中存在的裂纹状不连续性。它们可以分散在整个制备的样本中或集中在样本中的一个或多个位点。复合材料中的裂纹可能是由应力、化学反应和热老化产生的微观结构损伤引起的[2-4]。无损超声波工具可以检测材料中的各种不连续性。特别是，当使用脉冲回波技术时，可以表征各种不连续性。因此，预测裂纹的存在及其激活程度（例如外部应力激活）非常有用[56]。此外，还可以确定主要裂纹状不连续性的临界裂纹速度。预测裂纹的存在及其激活程度都有助于估计材料的使用寿命。这种估计继续指出，在指定的操作环境中，不连续性是否会增长或不会增长到足以在指定的时间间隔内导致故障的大小[7]。此外，主要裂纹状不连续性的临界裂纹速度可以提供有关给定结构寿命的有用信息。因为临界裂纹速度是断裂开始的速度并且超过一定限度，我们可以估计裂纹是稳定的还是不稳定的（即裂纹是稳定的还是分支的）[8]。材料和方法 1. 样品制备 复合树脂材料(CharmFil ® Plus) 是通过埃及开罗Trading Dynamic 公司从DENTKIST INC [韩国]购买的。 CharmFil ® Plus 材料用于前牙和后牙的修复。此外，该材料还具有一些良好的特性，如国际工程与技术杂志 IJET-IJENS Vol:14 No:03 2 141903-7272-IJET-IJENS © June 2014 IJENS I J E N S 良好的半透明性、优异的操作性和较少的残留单体。使用检验装置在室温下将 CharmFil ® Plus 材料 (4g) 与 CharmBond (A1) 和 CharmEtch (B1) 混合。然后，将混合物倒入准备好的模具中（图1）。我们等到混合物变成固体，然后将复合树脂样品从模具中取出。
Restorative materials, such as artificial heart valve, artificial members, artificial lens, etc, are regarded as abnormal materials that are implanted in a normal one. Nondestructive ultrasonic tool can characterize various materials. Therefore ultrasonic technique can be used to characterize restorative materials. Characterizing the implanted restorative materials is very important because these materials can be susceptible to various changes like the creation of inside cracks, surface or deep corrosion, etc. These changes can affect the work efficiency of the implanted restorative material. Ultrasonic pulse-echo technique was used to characterize various discontinuities in dental composite resin samples, which were susceptible to different tensile stress (50, 100, 150, 200, 250, 300 mm/min crosshead speed). The study showed that 100 mm/min crosshead speed is a critical load at which cracks are initiated in the dental restorative material. Otherwise, at 300 mm/min crosshead speed the material was broken, thus it can be said that this dental restorative material can sustain tensile stress below 300 mm/min crosshead speed. Index Term-Restorative materials, Non-destructive Ultrasonic tool, Cracks, Composite resin, Crosshead speed, Tensile stress. INTRODUCTION Composite resin fillings (white fillings) are a mixture of powdered glass and plastic resin, and it can resemble the appearance of the natural tooth. They are cosmetically superior to amalgam fillings, but they are more expensive than amalgam fillings. Dental composite resins are types of synthetic resins. They are insoluble, aesthetic, insensitive to dehydration and easy to manipulate. Composite resins are most commonly composed of Bis-GMA monomers, a filler material such as silica and in some applications a photoinitiator. Dimethylglyoxime can be added to achieve flow ability. Unique concentrations of each constituent achieve best physical properties. Unlike amalgam which essentially just fills a hole and requires retention features to hold the filling, composite cavity restorations when used with dentin and enamel bonding techniques restore the tooth back to near its original physical integrity. Nevertheless, amalgam has longer life to failure, but with poor aesthetic qualities [1]. Composite resin is an important industrial product. Therefore, it is regarded as an interested scope for study. Composite resin, as being susceptible to many conditions when implanted, can be a suitable site for various kinds of discontinuities. These discontinuities have a severe influence on the composite resin life time. The most common discontinuities are the crack-like discontinuities that are present in most composite materials. They can be dispersed all over the prepared specimen or concentrated in one or more site (s) in the specimen. Crack in composite may results from microstructure damage generated by stress, chemical reactions, and thermal aging [2-4]. Non-destructive ultrasonic tool can detect various discontinuities in a material. Especially, when using pulseecho technique, various discontinuities can be characterized. So it is useful to predict the presence of cracks and the degree of their activation (e.g. exterior stress activation) [56]. In addition, the critical crack velocity of the major cracklike discontinuities can be determined. Both the prediction of the presence of cracks and the degree of their activation, are useful to estimate the life time of the material. Such estimation goes on to state that if the discontinuities will grow or not to a size sufficient to cause failure within a specified interval of time in a specified operational environment [7]. In addition, the critical crack velocity of the major cracklike discontinuities can donate useful information on the life time of a given structure. Because the critical crack velocity is the velocity at which fracture commences and above a certain limit we can estimate if the crack will be stable or unstable (i.e. the crack will be steady or branched) [8]. MATERIALS AND METHODS 1. Specimen preparation The material of composite resin (CharmFil ® Plus) was bought from DENTKIST INC [Korea] by means of Trading Dynamic Company – Cairo – Egypt. CharmFil ® Plus material is used as restoration of anterior and posterior teeth. In addition, this material has some good characteristics like International Journal of Engineering & Technology IJET-IJENS Vol:14 No:03 2 141903-7272-IJET-IJENS © June 2014 IJENS I J E N S good translucent, excellent handling and less residual monomer. CharmFil ® Plus material (4g) were mixed with CharmBond (A1) and CharmEtch (B1) using a checker apparatus at room temperature. Then, the mixture was poured in a prepared mold (Figure 1). We wait until the mixture become solid, and the piece of composite resin specimen was removed from the mold.