The paper considers a physical research method for obtaining the parameters of the tensile strength of dental composite materials with different cross-sectional areas of samples. Obtaining tensile strength data will complement the existing characteristics of composites, so the work is relevant and promising for therapeutic dentistry. Five newest dental composites are investigated and described in the work. The functional diagram and appearance of the IM-4P breaking machine are presented. The work of IM-4P is described, as well as the installation of the sample before the test and its appearance after the rupture is shown. The results of the experiment were summarized in a table. The results of measurements demonstrating the dependence of mechanical stress (strength) on the cross-sectional area in dental composites are represented by polynomials of the third degree, the value of approximation reliability is determined, a sample with the best mechanical properties is identified.