Background. The risk of negative influence of unsuccessful selection of dental materials reveals the urgent need to use modern approaches in professional activity in order to provide the necessary quality of structures and their clinical and functional properties. The purpose of the study is to improve the quality of orthopedic treatment of patients with removable structures with an obturating part with two-layer bases due to the scientific substantiation of the selection of both soft substrates and acrylic plastics.
Materials and methods. A comparative assessment of the connection strength was carried out jointly with the employees of the central factory laboratory of JSC "Stoma" (Kharkiv, Ukraine) in accordance with the requirements of the international standard ISO-10139.
Research results. A comparative analysis of the study of the adhesion of A-silicon substrate materials to removable denture constructs made of acrylic plastics by various laboratory technologies included the results of a laboratory study of one of the most important physico-mechanical properties - bond strength. Investigation of bond strength (U, kgf / cm2) of material for soft substrates "PM-S" and acrylic polymer "Stomalite" found that its index is (5.3 ± 0.2) kgf / cm2 (Table. 1) and conforms to the regulatory requirements of ISO-10139. However, it was found that the index of the bond strength of the "PM-S" with the plastic "Pallopress" is equal to (5.5 ± 0.3) kgf / cm2, which is significantly (p <0,05) higher than the contact the material is "Villacryl H Plus" - (5.1 ± 0.2) kgf / cm2. The strength of the connection between the "PM-S extra" and the acrylic basis made from "Stomalite" is (6.9 ± 0.2) kgf / cm2, which exceeds the indicative index by 72.5% and is significantly (p <0 , 05) greater than in the combination of "PM-S" extra with "Pallopress" (6.8 ± 0.1) kgf / cm2 and "Villacryl H Plus" (6.7 ± 0.2) kgf / cm2. Polyvinyl siloxane material "PM-SN" is connected with acrylic plastic "Stomalite" with a strength of (9.3 ± 0.2) kgf / cm2. This indicator significantly (2.3 times) exceeds the indicative value (≥4.0 kgf / cm2) according to ISO-10139, which meets the quality requirements, and reliably (p <0.01) exceeds the results of research on the connection strength between "PM-CH" and "Pallopress" and "PM-SN" and "Villacryl H Plus", which are (9.0 ± 0.1) kgf / cm2 and (8.9 ± 0.2) kgf / cm2, respectively, and also meet the ISO requirements for this indicator. The study of the bond strength between the "Ufi Gel P" substrate and the "Stomalit" acrylic base plastics showed one of the best results throughout the study (9.1 ± 0.2) kgf / cm2, yet it is still inferior to the leading position of the "PM-CH"-"Stomalit" by 2.2%. However, in the "Ufi Gel P" bonding comparison group with other plastics, the result of the "Ufi Gel P" - "Stomalit" system was significantly (p <0,05) better than the "Ufi Gel P" - "Pallopress system" - (8.9 ± 0.3) kgf / cm2, which in turn inferior to the complex "Ufi Gel P" - "Villacryl H Plus" (8.8 ± 0.1) kgf / cm2. All of these systems comply with ISO-10139. The strength of the connection between materials "Silagum" and "Stomalite" is (5.9 ± 0.2) kgf / cm2, which corresponds to the normative requirements of ISO-10139 according to this indicator, but reliably (p <0.05) is slightly inferior to the system "Silagum" - "Pallopress" with a value of (6.0 ± 0.3) kgf / cm2, but 2.5% ahead of the connection "Silagum" and "Villacryl H Plus"- (5.8 ± 0.3) kgf / cm2 (p <0.05).
Conclusions. A generalized analysis of the results showed that all the studied systems meet the regulatory requirements of ISO-10139. However, the highest step in determining the compliance with the connection strength is the system of domestic materials "PM-SN" - "Stomalite". Prospects for further research are obvious and work in this aspect can be considered not only necessary, but necessary, as conducting studies of compliance of materials will undoubtedly significantly help the dentist's orthopedist to determine the choice of structural material in the manufacture of two-layer dentures.
Effect of Coating Thickness on Bond Behaviors of Polymer Cement Coated Plain Steel Bar with Concrete and Finite Element Modeling
