Dynamics of adhesive systems development in dental practice

Abstract

BACKGROUND: Тhe article presents a review of adhesive systems in terms of their component chemical composition. Seven generations of adhesive systems have been studied. The first generation of adhesive systems emerged in the 1970s. The result of the action was the bond reaction of the adhesive with calcium enamel and dentin. Glycerophosphoric acid dimethacrylate was used. The use of methacrylates in adhesive systems was widespread because polymers with high biological indifference to biological objects are formed when they are polymerized in combination with acrylic resin. The second generation used a lubricated layer to obtain higher adhesion rates. Chloro-substituted phosphate esters of various monomers were used as active groups. The main compound mechanism remained the ionic binding of calcium dentine by chlorophosphate groups. The third generation used a lubricated layer to attach the composite to the dentin in the same way as the second generation. In the chemical composition, aluminosilicates, aluminitrates, hydroxyethylmethacrylate (HEMA), 4-methacryloxyethyltrimethyl anhydride (4-META), and other substances were most often used as active groups. The fourth generation is a multicomponent system that provides a three- and four-step application technique. These systems contain three to four components (conditioner, primer, and adhesive). The technique of their use includes three stages, namely, etching with 37% orthophosphoric acid, priming, and bonding. Adhesive systems of the fifth generation are two-component systems that provide a two-step technique of application. First, acid (etching) is applied to the tooth tissue, and second, the adhesive itself. Adhesive systems of the sixth and seventh generations are one-component self-etching since the adhesive contains acid. From a chemical point of view, these adhesive systems are a mixture of phosphoric esters and adhesive substances. Therefore, analyzing the adhesive composition of seven generations in such way, the mechanism of chemical interaction of adhesive components with hydroxyapatite and dentin has not significantly changed; however, the number of hydrophobic fragments has increased, which significantly increases dentin contact.