GNATODINAMOMETRIYA (a jaw + force + metreo to measure Greek gnathos by dynamis) — measurement of force of the chewing pressure arising at compression of teeth as a result of reduction of masseters. It is applied to detection of sensitivity of a parodont to a functional load. On the basis of these data in dynamics functional changes of the basic device of teeth at development patol are studied. and recovery processes in to a parodonta (see), the optimum design of a denture is defined (see. Dentures ), providing recovery of function of dentoalveolar system.
There are special devices — gnatodinamometra (parodontodinamometra) which can be divided on mechanical, hydraulic and electronic.
The first mechanical gnatodinamometr designed G. V. Black in 1895; this gnatodinamometr is similar to the mouth gag, cheeks to-rogo are moved apart by the spring connected to the index, and on the ends the graduated scale is strengthened. At compression of cheeks of the device teeth the index moves on a scale and shows pressure force in conventional units. Further gnatodinamometr Blek was improved G. Haber in 1919 and M. S. Tissenbaum in 1941
I. A. Kleytman (1948) offered a spring parade ontodinamo meter, the principle of action to-rogo differs in the fact that pressure upon the studied teeth is made by effort of the researcher, and diversely.
In 1958. A. T. Busygin and M. R. Miller designed hydraulic gnatodinamometr which consists of the metal case filled with oil and connected by means of the pipeline to the manometer. On an upper part of the case there is a membrane and the nakusochny platform. During the pressing by the studied tooth on the platform the membrane caves in and forces out the corresponding oil quantity from the case, a cut moves on the pipeline to a cavity of the manometer, the arrow to-rogo shows pressure force in kilograms (in the vertical direction).
In 1960. I. S. Rubinov and L. M. Perzashkevich designed an electronic (piezoelectric) dynamometer; in it there is a sensor, in Krom the plate from brass and the coil of inductance contains. The sensor connected to the electronic generator and the microampermeter is imposed on teeth. With a pressure upon a plate the size of inductance changes that is noted on a scale of microamperes-meters.
Universal electronic gnatodinamometr (fig.), offered by V. Yu. Kurlyandsky, V. A. Nikitenko, V. A. Dubinsky, V. P. Shatunov F. I. Alekseev in 1970, turns on the measuring tool (head), the block of the amplifier — the indicator, the electrostrain gage with removable devices and the indicating device with two measurement ranges on the basis of the highly stable amplifier. The measuring head is supplied with three removable nozzles intended for measurement of endurance of a parodont to horizontal and vertical loading and for measurement of force of the muscles which are putting forward a mandible.
On the basis of researches a number of authors made tables of endurance of a parodont of teeth top and bottom jaws, and also separate teeth that can facilitate the choice of a design of a denture.
Bibliography Betelman A. I. Orthopedic stomatology, M., 1965; B at since y-@ and A. T N. Hydraulic gnatodinamo-meter, Stomatology, No. 6, page 86, 1968; Gavrilov E. I. and Oksman I. M. Orthopedic stomatology, page 39, 72, M., 1968; Konyushko D. P. Electronic pas-rodontodinamometr, Stomatology, jvft 5, page 106, 1963; Kurland V. Yu. The guide to a practical training to orthopedic stomatology, page 45, M., 1973; Perzashkevich L. M. An electronic dynamometer for measurement of force of transfer of pressure through teeth on parodont, Stomatology, No. 4, page 69, 1960.
S. I. Krishtab.