Comparative characteristics of the physical and mechanical properties of the self-etchangeable self-adhesive composite cement for indirect restorations "Maxcem Elite TM"

Summary. The article deals with an actual problem of orthopedic dentistry: the choice of a reliable material for fixing indirect restorations by comparing the physical and mechanical properties of self-adhesive self-etching composite cements. The aim of the study – to carry out a comparative analysis of self-etching self-adhesive double-fixation cements for indirect restorations in terms of physical and mechanical properties. Materials and Methods. For comparison, in terms of physical and mechanical parameters, a self-etching self-adhesive composite cement for indirect restorations "Maxcem Elite", Kerr, California, USA was taken. "Maxcem Elite" refers to self-etching self-adhesive composite cements of double fixation, which has a number of positive qualities, such as high physical and mechanical properties, good aesthetic properties, radiopacity. We analyzed the following physical and mechanical parameters: the appearance of the paste, depth of hardening, mm, diametric strength, MPa, conical yield point according to Heppler, MPa, hardness according to Heppler, MPa, water absorption in 7 days, μg/mm3, water solubility in 7 days μg/mm3, adhesive strength, MPa, peel strength, MPa. Results and Discussion. According to the average test depth of hardening (mm) material "Maxcem Elite" is inferior to others: material Bifix QV by 14.9 % and Relyx U 100 by 13.3 %. This does not significantly affect the quality of the connection of the adhesive structure with the hard tissues of the tooth, especially due to the method we have developed for the preparation of abutment teeth in the manufacturing of adhesive pads. On the other hand, according to the average value of the index of diametrical strength (MPa), the studied material "Maxcem Elite" is by 17.2 % better than Bifix QV, and by 17.3 % better than Relyx U 100. Comparing these and other physical and mechanical properties of materials on average, one must bear in mind the random nature of these values. From the results of the study, it can be seen that the difference between the indicators of the Maxcem Elite material and analogues is confirmed at a very high level of significance. The study of the level of water absorption indicates the probable absence of variability of the indicator of the studied material in comparison with comparable analogs. The value of the water solubility index of all the composites under study practically does not differ from the value of "Maxcem Elite" (within (2.5±0.1) %), and corresponds to the requirements of ISO 4046. Conclusions. The research results show that the investigated composite material "Maxcem Elite" in the main parameters corresponds to analogs, in most of the indicators it combines their best characteristics. In it, the adhesive strength of the connection with the hard tissues of the tooth is noticeably enhanced and better peel strength makes it possible to profitably use this material "Maxcem Elite" for fixing the adhesive structures.