Skubii I. Specific features of fixing mandibular complete removable laminar dentures applying samarium-cobalt magnets supported on intraosseous implants.

The thesis focused on the study of clinical and laboratory substantiation of increasing the prosthetic treatment efficiency for patients with removable laminar dentures in case of complete secondary mandibular adentia applying dental (samarium-cobalt) magnetic abutments supported on intraosseous implants. The objects of laboratory research were samples of samarium-cobalt type magnets (Sm2Co17 XGS30), subjected to sanitary-chemical and toxicological studies. The methodology of sanitary and chemical studies was aimed at obtaining the extracts from samples of samarium-cobalt magnets with subsequent determination of the content of renewable and organic impurities and a change in pH value. According to the data of the sanitary-chemical and toxicological studies, it was concluded that samarium-cobalt magnet samples do not contain renewable and organic impurities, do not change pH value, do not have histotoxic effect, and are biocompatible with the tissues of experimental animals at the place of their implantation. Based on the findings of the laboratory research methods, we developed the design of dental magnetic abutment adapted to intraosseous implant of the Classic type «Implife» company (Ukraine). The patent of Ukraine for utility model No. 94904 of 12/10/2014 was obtained for the magnetic abutment which we proposed. Clinical studies were carried out in three groups, the total number of patients amounted to 36. The masticatory efficiency was assessed while conducting chewing test with test material and subsequent analysis of the numerical data obtained. Chewing tests, evaluation of the crushed particles size and processing of the digital values obtained were carried out according to the author's method (Patent of Ukraine for utility model No. 101490 of 09/10/2015 "A method for functional assessment of masticatory efficiency"). We used our author's method (Patent of Ukraine for utility model No. 87372 of 02.10.2014 "A method for evaluation of occlusal contacts of antagonizing teeth") for the assessment of occlusal contacts characteristics in patients of research groups. The study of color indicators of the prosthetic bed mucosa at the stages of prosthetic treatment was carried out with patented author's method (Patent of Ukraine for utility model No. 88400 of 03/11/2014 "A method for detecting the oral mucosa inflammation at the stage of prosthetic treatment"). Based on the statistical analysis and generalization of the clinical findings, we came to the following conclusions. The findings of chewing tests, namely, the increase in the total number of fragments and the decrease in their area indicate the masticatory function improvement and functional adaptation to removable dentures in patients of both research groups. But, when comparing the indicators of the average value of the average area of all fragments, we determined that the first research group presented higher indicators, both on day of fitting dentures and 30 days after prosthetic treatment. The increase in the average value of the total number of fragments from the day of fitting the removable dentures on 30 day was less in the first research group than the corresponding indicator in the second one. Thus, the additional fixation of the complete mandibular removable dentures with dental magnetic abutments supported on intraosseous implants demonstrated advantages in terms of masticatory efficiency both at the early stages after the dentures manufacturing and in the long-term follow-up. The data of digital occlusiography made it possible to determine that the value of occlusiographic indicators (average value of the pressure area and average value of the average pressure force) were significantly higher in the second research group, considering the period of use of the removable dentures. The high values of occlusiographic indicators in the second research group detect the greater functional ability and confirm the positive value of intraosseous implants as the factors for rational redistribution of chewing pressure. The findings of the average values of color indicators of the prosthetic bed mucosa in patients of the research groups were statistically comparable on the day of examination. The decrease in the average numerical values of the indicators of research groups were observed on 7 day, but more significant they were in the second research group due to hyperemia caused by the vascular response to surgical intervention. The data obtained on 30 day were characterized by the increase in the average value of color indicators in patients of both research groups. However, they were much more significant in the second group. This fact proves the effect of the mechanical load of the removable laminar structure on the hyperemia degree of the prosthetic bed mucosa and the most successful course of adaptation processes in the second group patients.