THE EVALUATION OF CURRENT RESEARCH ON THE STRENGTH OF DENTAL RESTORATIVE COMPOSITE MATERIALS

Abstract

The aim of the study: to analyze the sources of scientific and metric information on the state of research on the strength of dental composites for tooth restoration.
 It has been determined that the range of composite materials available on the dental market is very wide. They differ significantly in chemical, mechanical, physical, and biological characteristics, operating properties, techniques of their usage. All this requires special training to use the composites effectively and to get high quality restoration results. The optimal choice of material and suitable technique taking into account a particular clinical situation can increase the durability of restorations and prevent the development of complications that largely depends on the strength characteristics of composites.
 At present, the problem of selecting and creating the perfect filling material has not been completely solved that is confirmed by the large number of new developments in materials science. At the same time, composite polymers are gaining ground in dental practice. The new concept of adhesive preparation of dental tissues before inserting filling material and improving the properties of the composite materials themselves contribute to the maximum preservation of healthy dental tissues, increase the aesthetics, durability and functionality of dental restorations.
 It has been determined that the mechanical strength characteristics of composite materials play a significant role in the longevity/durability of restorations depending on different chewing force and occlusal loading. It is important to investigate factors, which may cause the destruction of dental composites during the functional loading.
 The physical and mechanical properties of dental composites are impacted by a number of factors, including the type of polymer matrix, the amount of material takes, size and distribution of the filler, the state of the bond between the filler and the matrix, the degree of polymerization. The choice of a material also depends on a number of characteristics in terms of the combination of main components. Since the material parameters set by the material manufacturers can not be changes, the deep understanding of its properties will help to choose the best material in each clinical situation.
 The main physical properties of dental composites include compressive and tensile strength, modulus of elasticity, coefficient of thermal expansion, wear resistance, polymerization shrinkage, X-ray contrast, density and thixotropy, optical effects (transparency, fluorescence, etc.).
 The AE method based on the registration of elastic waves arising from the formation, change and destruction of the structure of various materials, is currently the most effective for studying the processes and stages of development of material defects. It enables in detecting initial changes in the material structure, the initial location of defects, the direction of their spreading and determining the maximum strength of the material. The advantages of this method include the ability to obtain information about the destruction in the early stages, its high accuracy and sensitivitys.
 The AE method is commonly used to study the resistance to destruction of various composite materials, the study of the tooth / composite interface, the analysis of polymerization stresses and the degree of shrinkage.