FIXED PROSTHETIC CONSTRUCTIONS WITH USING OF HIGH VOLUME DIGITAL SCANNING TECHNIQUES

the heterogeneity of the wheat plant's structure - at 83.3%, the increase in size at 61.1%, subcapsular changes of the parenchyma - in 16.7% of cases. More accurate and extensive information obtained with spiral CT. In patients with suspected HCC and kidney injury ultrasound should be performed immediately upon admission and again within 1-2 days. Spiral CT allows more accurate and clear picture of retroperitoneal bleeding, determine the severity of kidney injury and the condition of the structure of the parenchyma. mm in this clinical case. To sum everything up, we can say that the experiment with using the Digital high volume scanning to determine the depth preparation of the experimented teeth by the young dentists, enables more accurate and carefully approach to the rationality of the depth of odontopreparation for non-removable prosthetic constructions. At a frequency of 8.0 kHz in patients with a teflon tube (T/tvt) - the magnitude of this indicator increases in the first 3 months after surgical intervention, and then gradually decreases after 6 and 12 months after the operation, and in patients with a silicone tube (T/svt) - practically does not change during all time after surgical intervention. The dynamics of thresholds for the perception of bone-carved sounds at different frequencies in patients with T/tvt after surgery is in most cases of a multi-directional nature. In patients with T/svt, the perception of bone-carved sounds at a frequency of 4.0 and 8.0 kHz increases in the first 3 months after surgical intervention, with subsequent preservation of its level until the 12th month after surgery. The dynamics of bone-air intervals at frequencies of 0.5 and 1.0 kHz in virtually all groups of patients with CTOM (except for T/tvt at a frequency of 1.0 kHz) after surgery has a similar nature - a gradual decrease with an increase in time after surgery (3 – 6 – 12 months), and the most pronounced decrease is observed in the first 3 months. At the frequency of 2.0 and 4.0 kHz, in most groups of patients with CTOM, the most pronounced reduction of bone-air intervals is noted not only after 3 months, but also in the interval from the 3rd to the 6th month. At a frequency of 8.0 kHz, the gradual decrease in the value of bone-air intervals with the increase in time after surgery is observed in the group of patients with T/svt, in patients with T/tvt its magnitude increases after 3 months after surgery, and in the interval between the 3rd and in the 6th months it decreases and then practically does not change.

A prosthetic dentistry developed many different methods of preparing teeth for metal-ceramic constructions, but the pulp condition during preparation was not taking into account, so there is no informed medical tactics to preserve or extract pulp of abutment teeth [2,6,8,11]. With the aim of studing the functional state of the supporting teeth, a series of analisis proved that the previous preparation and depulpation of abutment teeth for the manufacture of metal prosthesis was incorrect. However, even following the generally accepted protocols of teeth preparation, there is a significant percentage of complications after preparation, because of the improper preparation of abutment teeth. Usually, dentists apply the preparation of abutment teeth without ledge. Also it might be found an excessive removal of hard tissue and creating a large obliquity of walls, which leads to the injuries of pulp [1,5,9,10] and worsen the finished stage of prosthesis fixation. These complications often occur the beginners in dental prosthetic dentistry due to the lack of experience and inadequate position in assessing the clinical situation.
Research purposeto determine the depth preparation of the examined teeth with high volume digital scannig.
Мaterial and methods. To identify morphological changes of hard tissue of examined vital teeth with using a various types of odontopreparation with full metal-ceramic crowns, it was studied 6 premolars of the upper and lower jaws of patients aged between 18 to 29 years. The material was divided into two research groups. As a control group was taken the average data standards of morphology and functional characteristics of the pulp and dentine with appropriate functional group of the teeth. The experiments were conducted on the same teeth of a jaw from different sides. The first experimental group included cases where odontopreparation of premolars was done with the creation of the classic rounded beveled ledge in the cervical part, the second groupthe cases in which odontopreparation of the premolar crowns conducted with maximum preservation of cervical crown (symbol of the ledge).
In order to improve the accuracy of the depth preparation of tooth stump, was used the technology of high volume digital system scanning CAD / CAM -Computer Aided Design / Computer Aided Manufacturing. Produced collapsible gypsum models for each clinical case and scanning system CAD -digital surround scanner «Arcad Premium» on the unit «CAD / CAM ARCADIA». With that technology for 3D models was determined the exact depth preparation of tooth stump [23, 4,7].
Results and its discussion. Through digital high volume scanning of gypsum models with prepared teeth of the first research group confirmed that the average depth preparation with classic beveled rounded ledge from 0.6 to1.0 mm in different clinical situations ( Fig. 1). In order to determine the depth of preparing hard tissues in creating bevelled classic rounded ledge in the cervical area, the system CAD -volume digital scanner «Arcad Premium» on the unit «CAD / CAM ARCADIA» was modeled an artificial crown and received data about its thickness ledge area, which is 0.845 mm in this clinical case. The second group of observations included cases in which odontopreparation for full metalceramic crowns conducted with maximum preservation of cervical hard tissues of the tooth crownforming the «symbol ledge». To determine the depth of preparation of dental hard tissues when creating a «symbol ledge» in the cervical area, as in the previous case was made unmodeling artificial crown, and obtain data of its thickness in the area of the ledge, which is 0.319 mm in this clinical case (Fig. 2).

Conclusion
We can say, that the experiment with using the digital high volume scanning to determine the depth preparation of the experimented teeth by the young dentists, enables more accurate and carefully approach to the rationality of the depth of odontopreparation for non-removable prosthetic constructions.
Рецензент Аветіков Д.С. At a frequency of 8.0 kHz in patients with a teflon tube (T/tvt) -the magnitude of this indicator increases in the first 3 months after surgical intervention, and then gradually decreases after 6 and 12 months after the operation, and in patients with a silicone tube (T/svt) -practically does not change during all time after surgical intervention. The dynamics of thresholds for the perception of bonecarved sounds at different frequencies in patients with T/tvt after surgery is in most cases of a multi-directional nature. In patients with T/svt, the perception of bone-carved sounds at a frequency of 4.0 and 8.0 kHz increases in the first 3 months after surgical intervention, with subsequent preservation of its level until the 12th month after surgery. The dynamics of bone-air intervals at frequencies of 0.5 and 1.0 kHz in virtually all groups of patients with CTOM (except for T/tvt at a frequency of 1.0 kHz) after surgery has a similar nature -a gradual decrease with an increase in time after surgery (3 -6 -12 months), and the most pronounced decrease is observed in the first 3 months. At the frequency of 2.0 and 4.0 kHz, in most groups of patients with CTOM, the most pronounced reduction of bone-air intervals is noted not only after 3 months, but also in the interval from the 3rd to the 6th month. At a frequency of 8.0 kHz, the gradual decrease in the value of bone-air intervals with the increase in time after surgery is observed in the group of patients with T/svt, in patients with T/tvt its magnitude increases after 3 months after surgery, and in the interval between the 3rd and in the 6th months it decreases and then practically does not change.
Among the diseases of otolaryngology organs, treated stationary, the frequency of chronic purulent otitis media is 20-25% [10] and may cause disability in patients with deafness and the development of such intracerebral complications as meningitis, encephalitis, brain abscess, sigmoid sinus thrombosis, etc. [2,9,15,18]. In patients with a sufficient function of the auditory tube after eliminating the inflammatory process in the area of the middle ear, nose and nasopharynx, the predictions of surgical