THE LABORATORY STUDY ADHESIVE BOND STRENGTH OF PHOTOCOMPOSITION MATERIAL WITH TOOTH ENAMEL

Abstract

Abstract. Formulation of the problem. The structural and functional teeth enamel acid resistance with a viable pulp can in a certain way influence the depth of acid microdefects in the enamel after its etching during the adhesive preparation of hard tissues for restoration and the strength of the adhesive bond of photocomposites with the enamel of teeth restored. The aim. Laboratory assessment of the adhesive strength of the photocomposition material with tooth enamel, depending on the initial structural and functional enamel acid resistance and the time of its etching. Materials and methods. The study was conducted on 80 samples made from extracted chewing teeth with a preliminary determination of structural and functional tooth enamel acid resistant in patients, depending on the level of which they were divided into four groups. Enamel etching was performed for 15 and 30 seconds in tooth samples of patients of groups I and II with high and medium levels, and for 15 and 30 seconds in tooth samples of patients of groups III and IV with low and very low levels. The strength of the adhesive bond between the photocomposite and the enamel was investigated for separation and shear. Results. In the samples of the people teeth of the I group, the indicators of the strength of the adhesive bond for separation and shear were 28.82±0.97 and 19.72±1.19 MPa, in the samples of the patients teeth of the II group, the indicators were equal to 34.90±1.81 and 23.90±2.06 MPa, III groups – 25.11±1.27 and 16.33±1.30 MPa, IV groups – 20.80±1.67 and 14.90±1.19 MPa, respectively. Indicators of the strength of the adhesive bond in the samples of the teeth of individuals of the II group were always probably (p<0.05) higher than other corresponding values. Conclusions. The results of the study demonstrated the need to extend the period of acid exposure to enamel to 30 seconds during adhesive preparation for direct teeth restoration of patients with a high or medium level of structural and functional enamel acid resistance, while in patients with low or very low acid resistance, increasing the etching time is impractical.