VARIETY AND PRINCIPLES OF COOPERATION OF DOUBLE CROWNS OF TELESCOPIC CONNECTIN
Authors: Tarashevska Yu. Ye. , Shyyan Ye. G. 
Published: July 2019

For today, problem of fixing of partial removable prostheticappliances, and more precisely it remains not fully decidedthe term of endurance and worn down of friction propertiesof telescopic connections. Therefore, the search for improvement of fixative properties of telescopic connection sremains actual.
Material and methods: Analytical study of scientific sources on the problems of replacing defects in dentition with removable dentures with fixation on telescopic crowns.
The aim of this work consists in that, to educe, to estimateand compare, on thebasis of the dynamic supervisions, scientific-medical information, views of authors on the role and definition of interaction of double crown sof telescopic connection, especially with the use of auxiliaryel ements of fixing.
Appearance of double crowns with a resident interval, offered Strack and Hofmann in 1966, induced scientists to perfect and develop the new auxiliary elements of fixing for the improvement of retention properties of telescopic connections. The process of search took place and takesplace in various ways: - by the use of various materials (gold, ordinary alloys, thermosetting and thermoplastic polymers, powder-like metals and compos); - by the use of different technologies (punching, founding, milling, electrotype, spark-free treatment, 3d printing); - by development of new auxiliary elements ( retention pins, rings, plunger, crossbar, attachments, hobs, petals et al); - by the use of other physical phenomena ( diffusion, dry technicians, vacuum, magneti, rheological properties).
The article also highlights the views of scientists on the negative and positive aspects of the proposed technical solutions. It is informed about the proposed radically new system of telescopic connection, which is based on the use of another physical phenomenon - the rheological property of materials.
The uses of the known methods, new or improved additional structural elements are mainly based on bringing of those or other changes in the primitive construction of telescopic connection. Analysing the advanced studies of many researchers, it is possible to draw conclusion that advantages of fixing of removable prosthetic appliances by means of the telescopic systems are determined by the row of their possibilities. To basic advantages of double crowns it is possible to take a complete scope the external crown of supporting teeth with simultaneous implementation of retentive, stabilizing, directing and supporting functions, and also distribution of horizontal power components of the functional loading, and wide possibility of choice of the offered additional construction elements extends possibility to the specialists in the rational system of choice of the telescopic fixing.
It would be desirable to mark that the telescopic system is theoptimal method of fixing of prosthetic appliance in comparingto another ways of fixing of partial removable prostheticappliance that is confirmed by the researches conducted inthis matter.
Conclusion: Thus, it was educed on the basis of review of correspondingliterature, that the best terms for proceeding in masticatoryefficiency, function and aesthetics of the tooh-jaw system removal of deformation of occlusion surface of dentalrows and injuring bite for patients with the partial loss of teethit is succeeded to obtain at the use removable prostheticappliances with the telescopic system of fixing, especially withthe use of additional structural elements.