MATHEMATICAL MODELING OF THE STRESS-STRAIN STATE OF THE TOOTH ROOT SYSTEM OF PIN CONSTRUCTIONS

Yanishen I. V., Bilobrov R. V., German S. A., Biryukov V. A., Saliya L. G.

METHODS AND METHODOLOGIES

Scentific article

Restoration of destroyed teeth with total defect of the crown part is one of the most problematic issues of orthopedic dentistry. Based on the clinical trial data, the orthopedic dentist should choose from a large number of different pin designs that would be fully suited to the clinical situation. The most controversial questions remain related to the preparation of the root part of the tooth, the choice of the optimal design of the insert, the material for its manufacture. In the future, both cylindrical and conical and cylindrical conical pins are used. The question of the best form remains open. The purpose of the work was to provide the analysis and calculation of stresses arising in the modeled system of the root part of a single root tooth in the preparation of the canal for pin designs of various shapes. Object and methods. Mathematical modeling of the stress-strain state of the tooth root system with the installation of stump inserts was performed. We used the widely known ANSYS finite element analysis software package for WINDOWS. Geometric volumetric models of repurposed single root teeth for pins of various shapes were compared, followed by the shape of the stump. The data for comparative calculation we have taken from the methodology of the three-dimensional survey of the proposed Marxkors on hub cylindrical Optipost pins. For Marxkors, the measured root lengths of the upper central incisors are from 11.0 mm to 20.5 mm, and for Sahakyan root length of the central upper incisor is less than the fang by 4 mm. The results and discussion. The results of the analysis of geometric bulk models are established that the cylindrical design of the pin has worse performance compared to the stepped design with variable cylinders. Most of all, horizontal stresses for a pin with a depth of 21.1 mm were determined in a cylindrical structure of 1.91 MPa versus 1.55 MPa stepwise and 1.24 MPa conical. The cylinder has a better vertical stress of 6.18 MPa, a cone of 6.13 MPa has almost the same performance, and a lower rate of 4.84 MPa in a stepped design. Conclusion. According to these data, it can be concluded that for a cone it is necessary to perform rounding at the lowest point to relieve vertical stresses. The greatest stresses arise with the cylindrical design of the pin in its lower part. For a stepwise structure of the destruction of the tooth walls, it is possible in the area of 2/3 of the height of the pin, while the force must be applied more than for a cylindrical pin. The conical structure will require even more effort to destroy the root, while it is more likely in the apical area of the pin.

pin constructions, mathematical modeling, pin designs, total defect of the tooth crown, tension in the root of the tooth.

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«Bulletin of problems biology and medicine» Issue 1 (155), 2020 year, 264-270 pages, index UDK 616.314.16-085.465:519.87

10.29254/2077-4214-2020-1-155-264-270