No abstract

Запропонована удосконалена технологія виготовлення двошарових повних знімних пластинкових протезів з використанням самотвердіючих еластичних базисних матеріалів. Запропоновано методику виготовлення безкламерних часткових знімних пластинкових протезів з використанням самотвердіючих еластичних матеріалів при наявності поодиноких зубів і приведено її оцінку за результатами клінічних спостережень.

The aim of the study was to improve the effectiveness of orthopedic treatment for patients with dentition defects by method of making a removable denture with claspless fixation, taking into account the mathematical modelling of the teeth and undercut inclination. The technique of making claspless partial dentures by using A-silicone material is based on the idea of using the elastic forces generated in the wedge-shaped body of elastic material under the influence of an external force, which resets the prosthesis. Based on the considerations, it was developed a scheme of  the claspless denture model and the mathematical modeling of partial removable laminar dentures fixation with elastic material, resulting in the special formula. After analyzing the results, we suggest to use in the clinic simplified table. With their help, you can easily determine the rationality of claspless denture, which is planned to produce on the technology that we offer. For this, you need to determine the ratio of the magnitude undercut and height of the inclined teeth and to compare them with the data tables. The most efficient should be considered claspless design of the prosthesis, if both of the inclined abutments have a ratio of the magnitude of undercut and height not less than the value of the ratio when the value F/2=0.3 kg U= 1 mm. In this case, it can be argued that claspless prosthesis under the influence of dropping efforts 0,3 kg will move in the vertical direction not more than 0.5 mm, and under the influence dropping efforts to 0.6 kg not more than 1 mm. But, if one or both of the sloping supporting the tooth have the ratio of the magnitude undercut and a height of about one (an angle of about 45°), then there will be difficulties with the insertion of claspless denture on the prosthetic bed. Thus, the fixation and stabilization of the claspless denture will be carried out using wedge-shaped body of elastic material, the amount of which is calculated individually depending on the above parameters and fills the area between the denture and supporting teeth of the patient. The optimal ratio of undercut and height of the inclined teeth is discussed. When the mesio-distal tilt angle is more than 45°, there are difficulties with the insertion of the prosthesis, and when tilted less than 15° it can have problems with fixing. Allowed the thickness of the silicone compound is from 0.1 to 2.4 mm When the thickness of the layer of material above 3.0 mm are possible complications in the form of breaking on period of exploitation.

The aim of the study was to compare the obtained data of hard dental tissues destruction indices with the corresponding indications for the choice of the method of treatment by means of mathematical analysis. Materials & methods. 120 patients aged 20 to 55 were examined and 358 teeth hard tissue defects were identified in them. The data of indices was obtained and compared with the indications for orthopedic treatment according two indices in the same clinical situation. Results. The study showed that the indices had different meanings and different indications for treatment in the same situations. Such discrepancies in indications for treatment indicate the subjective data of one of the indices, which does not take into account the depth of destruction and the volume of the remaining natural tissue of the teeth. Comparison of these indices showed different figures in the same clinical situation, identifying corresponding incorrect indications for the choice of the design of the first investigated index, as well as more accurate data of the proposed index. Conclusion. The index assessment of hard dental tissues destruction serves as the main guideline for the dentist when choosing a method for tooth restoration, and can be calculated using photographs, scans and computer software.