Functional analysis of the results of using Ufi Gel P elastic soft lining from VOCO (Germany) as a means to reduce the time of adaptation to removable plate prostheses in the process of prosthetic rehabilitation of patients with asymmetric distally unlimited defects of dental rows in the early stages

Objectives. Study of ways to increase the efficiency of immediate prosthetic treatment of patients with asymmetric distally unlimited defects of dental rows by using clinical relining of partial removable dentures with Ufi Gel P material from VOCO (Germany) to reduce the time of adaptation to dentures and normalize the functional activity of the masticatory muscles. Materials and methods. The efficiency of clinical relining of partial removable dentures using an elastic lining with Ufi Gel P from VOCO (Germany) was evaluated by electromyographic examination with BioEMG III electromyograph from BioRESEARCH Associates, Inc. (USA). The bioelectrical activity of the temporal and masseter muscles was evaluated during maximum voluntary clenching and mastication. The quantitative indicators of the amplitude of biopotentials (μV) and the qualitative characteristics of the chewing cycles were evaluated. Results. Our study has revealed that patients with asymmetric distally unlimited defects of dental rows had shown a significant decrease in the amplitude of biopotentials of the masticatory muscles compared to patients in the control group during maximum voluntary clenching and chewing, as well as a significant asymmetry of the bioelectric activity of the masticatory muscles on the right and left. During mastication there were significant differences in the size and duration of chewing cycles, a decrease in the duration of rest periods and the average number of chewing movements increased almost two times compared with intact dentition. A month after prosthetics, the indicators of bioelectrical activity of the masticatory muscles improved in both study groups of patients, but the most significant increase in amplitude was observed in the second group with a soft lining. There was also revealed a significant increase in the symmetry of bioelectric activity of the masticatory muscles, an improvement in the characteristics of the masticatory cycles and normalization of the activity and rest periods duration ratio in patients of the second group, while in patients of the 1st clinical group the indicators of symmetry did not change significantly. The average number of chewing movements required to chew the hazelnut kernel decreased to 38.7±16.2 and 29.3±10.7 respectively, in groups 1 and 2, which indicates an increase of masticatory efficiency. Conclusions. In the framework of this study, the high efficiency of Ufi Gel P (VOCO) elastic lining for the successful rehabilitation of patients with asymmetric distally unlimited defects in case of early prosthodontic interventions was proved. Our observations have shown that the use of the Ufi Gel P (VOCO) soft lining significantly increases the functional parameters of the masticatory system, shortens the period of adaptation to removable dentures and supports the formation of the alveolar processes relief without irregularities.

Analysis of the results of using elastic soft lining as a means to reduce the time of adaptation to removable plate prostheses in the process of the early prosthetic rehabilitation of patients

Objectives. Study of ways to increase the efficiency of immediate prosthetic treatment of patients with asymmetric distally unlimited defects of dental rows by using clinical relining of partial removable dentures with elastic material to reduce the time of adaptation to dentures and normalize the functional activity of the masticatory muscles. Materials and methods. The efficiency of clinical relining of partial removable dentures using an elastic lining with Ufi Gel P from VOCO (Germany) was evaluated by electromyographic examination with BioEMG III electromyograph from BioRESEARCH Associates, Inc. (USA). The bioelectrical activity of the temporal and masseter muscles was evaluated during maximum voluntary clenching and mastication. The quantitative indicators of the amplitude of biopotentials (μV) and the qualitative characteristics of the chewing cycles were evaluated. Results. Our study has revealed that patients with asymmetric distally unlimited defects of dental rows had shown a significant decrease in the amplitude of biopotentials of the masticatory muscles compared to patients in the control group during maximum voluntary clenching and chewing, as well as a significant asymmetry of the bioelectric activity of the masticatory muscles on the right and left. During mastication there were significant differences in the size and duration of chewing cycles, a decrease in the duration of rest periods and the average number of chewing movements increased almost two times compared with intact dentition. A month after prosthetics, the indicators of bioelectrical activity of the masticatory muscles improved in both study groups of patients, but the most significant increase in amplitude was observed in the second group with a soft lining. There was also revealed a significant increase in the symmetry of bioelectric activity of the masticatory muscles, an improvement in the characteristics of the masticatory cycles and normalization of the activity and rest periods duration ratio in patients of the second group, while in patients of the 1st clinical group the indicators of symmetry did not change significantly. The average number of chewing movements required to chew the hazelnut kernel decreased to 38.7±16.2 and 29.3±10.7 respectively, in groups 1 and 2, which indicates an increase of masticatory efficiency. Conclusions. In the framework of this study, the high efficiency of elastic lining for the successful rehabilitation of patients with asymmetric distally unlimited defects in case of early prosthodontic interventions was proved. Our observations have shown that the use of the soft lining significantly increases the functional parameters of the masticatory system, shortens the period of adaptation to removable dentures and supports the formation of the alveolar processes relief without irregularities.

Development of the theory of laying a hoisting rope on the drum of a mining hoisting machine

For new designs of mine hoisting machines, the development of scientifically-based solutions to increase the rope capacity and reduce the size of the machines is relevant. Based on the theory of laying the rope on a lined cylindrical drum developed by the authors, it is shown that when choosing a groove profile and winding pitch for a non-lined drum, it is necessary to use a geometric rope laying model, and for taking into account the elastic lining, it is necessary to use a physical model of static interaction of a rope with a scallop of the groove. It is recommended to use the U-tilda-groove profile, which will allow a 4.5 % increase in the drum capacity while maintaining the rope’s curvature radius that is permissible under safety rules during its installation.

Justification of the algorithm for selecting the parameters of the elastic lining of the drums of mine hoisting machines

When calculating the stress-strain state of a cylindrical drum of a mine hoisting machine loaded with a metal rope, the stiffness parameters of the elastic lining and frontal surface are taken into account. It is defined that, depending on the values of the radial and bending stiffness of the frontal surface, two zones can be distinguished. If the parameters of the frontal surface fall into the first of them, the stresses in the shell slightly differ from the stresses in the hinged supported shell. The second zone is characterized by a sharp (up to 70%) increase in stresses. An algorithm has been developed for selecting rational parameters of a lined drum, which allows to reduce the stresses in the metal shell by up to 20%.

METHODS OF PREPARATION OF PROSTHETIC BED TOOTHLESS LOWER JAW BEFORE THE PROSTHESIS (LITERATURE REVIEW)

The article presents a scientific overview of the literature on the actual problem restorative dentistry: preparation low-supple atrophied tissue prosthetic bed before the prosthesis patients with complete absence of teeth in the lower jaw. Despite significant progress in prosthetic dentistry, the problem of prosthesis patients with complete absence of teeth on the lower jaw does not lose its relevance. From 15 to 46% of patients aged 45-70 years, need to manufacture complete dentures. One of the factors that directly affect the fixation of complete removable lamellar denture for the lower jaw is a condition of the mucous membrane of prosthetic bed. The most unfavorable for prosthetics full removable laminar dentures is considered as grade 2 mucosa classification Supple. This class is characterized by thinned, stretched and dry mucous membrane of the prosthetic bed. To achieve success in the orthopedic treatment of such patients need to restore the volume and pliability of the mucous membrane of toothless prosthetic bed. A study of the basic methods of surgical, orthopedic, physiotherapy preparation of tissue prosthetic bed toothless lower jaw, and combinations thereof. Of the known methods of noteworthy ways of plastics of the alveolar part of the mandible and increase in volume of soft tissues of the prosthetic bed toothless method Plasmolifting, and the combination of the introduction of autoplasma rich in platelet with the production time immediat dentures with elastic lining. Describes the advantages and disadvantages of the proposed methods. Despite the many different ways of preparation of prosthetic bed before prosthetic treatment, this problem remains unsolved and requires further study.

A tridimensional finite element approach to model a tunnel with shotcrete and precast concrete

ABSTRACT This paper describes a numerical simulation with 3D finite elements of a tunnel. The viscoplastic law of Perzyna represents the rockmass behavior. The concrete, shotcrete or precast, is modeled as a viscoelastic material through the Maxwell and Kelvin chain models. Finite element simulations are performed by incorporating subroutines for viscoelastic concrete models in the ANSYS code. The method to simulate tunnel excavations is by activating and deactivating elements in sequential steps. In the first part of the paper two validations are performed. The analytical solution and the deformation achieved on the stabilization in the ANSYS code are compared with an unlined tunnel. A lined tunnel, with an elastic and viscoplastic rockmass combined with an elastic lining, is compared with the results of the GEOMEC91 code. In the second part, it is compared the same tunnel with two different concrete lining for two chain models. Finally, it is modeled the Kielder experimental tunnel, which in situ measured data is available.

Scttering of SH-Waves by Interface Semicircular Debonded Cylindrical Lining and Linear Cracks Originating at Edge of Lining

The Green function and other complex functions were employed to study the problem of scatteing of SH wave by a interface semicircular debonded elastic lining of two-phase mediums and interface linear cracks originating at edge of lining. We divided the whole model into upper elastic half space with the semi-circular canyon and lower elastic half space with semi-circular lining hill.In lower half space. Semicircular debonded elastic lining is constructed by satisfing the continuous condition of displacement and stress on interface when upper half part and lower half part are conjoined,and linear cracks is constructed by using the method of crack incision, upper half part and lower half part are conjoined by method of “conjunction”.In the end some examples and results of dynamic stress intensify factor are given with discussions.

Mechanics Model and Experimental Researches on Hydraulic Expansion Lining of High Pressure Reactor

New hydraulic expansion technique was invented, and conjoint results were also estimated. High pressure reactor’s overall water pressure test is used to expand lining plastic deformation, and then eliminate the gap between lining and shell. According to elastic-plastic theory, the mechanics model was induced. The conjoint result was estimated by measured layer gap, stress and strain. The results show that theoretical calculation is basically consistent with actual results, the biggest error is 13.8%; although the biggest preliminary gap reaches 16mm, remnant gap is only 0.6~0.9mm after hydraulic expansion; during pressure increase test, shell material always keeps elastic. Lining and shell almost become an integrated material after the initial pressure more than 3.1MPa, the linearity between cylinder stress and initial pressure is more than 0.99.

Soft roll linings - better conduits: First press of the PS 2, paper machine, Belisce, Croatia

Paper with demanding technical properties is formed in the press of the paper machine when the paper pulp is passed between the rolls. In order to form paper in the appropriate manner, an elastic lining with particular stiffness is spread over the rolls. In this study a practical example of how softer linings generally give better results concerning the percentage of the dry part and the paper structure is presented. From the rubber roll manufacturers' point of view, the weak side of soft linings lies in greater deformations, which present difficulties in obtaining good adhesion between the lining and metal core of the roll. Only the best manufacturers in the industry can match such high demands.