Excessive Abrasion Research Articles

Improving surface finish and wear resistance of electroless nickel plating using flexible abrasive tool

Electroless nickel plating has a variety of useful properties, including high hardness, high stability, and better corrosion and wear resistance when compared with the stainless steel substrate used in the present work, which make it useful in different fields such as aerospace, optics, defence, etc. However, these applications require very high level of surface finish. This work presents the finishing of electroless nickel plating by flexible abrasive tools fabricated by solvent dissolution method. The flexibility of the tool allows for better adaptability to the workpiece surface, thus protecting the surface from excessive abrasion from abrasive particles. The topographical and morphological studies of the as-plated surface are carried out and compared with the finished surface. Surface roughness, material removal rate and forces are measured to understand the material removal mechanism. Tool loading is also analysed to understand the tool performance. Final finishing is carried out using the best set of input parameters, with or without tool conditioning. A final surface roughness of 9 nm is achieved in 24 min when finishing is carried out using tool conditioning. The wear test and hardness testing of the as-plated and final finished surfaces is carried out to understand the performance of the component. The final finished surface has the lowest coefficient of friction and the maximum wear resistance.

Prediction of concrete abrasion depth and computational design optimization of concrete mixtures

The failure of concrete for hydraulic structures due to the excessive abrasion depth has caused great economic losses. Despite the tremendous work that has been done, the durability design of hydraulic concrete structures concerning abrasion damage is still a difficult task, especially with a long service life aiming at economic benefit and environmental sustainability. In this paper, machine learning methodologies including random forests (RFs) and artificial neural networks (ANNs), are used to establish prediction models based on concrete mixture proportions, curing age, and hydraulic conditions. Furthermore, RF models are coupled with multiple objective particle swarm optimization (MOPSO) algorithms to perform computational design optimization of concrete mixtures. The optimal solutions are generated based on 5000 randomly generated mixture proportions, among which three optimal designs of concrete mixtures are selected to guide field applications on account of concrete durability requirements and economic benefits.

MATHEMATICAL SUBSTANTIATION OF BIOMECHANICAL BASES OF PATHOLOGICAL WEAR OF HARD TISSUES OF TEETH

Using the Bernoulli principle, the muscles that raise, laterally shift, and advance the mandible were studied. The biomechanical component of the pathogenesis of pathological tooth abrasion was revealed. The role of "fast" and "strong" muscles in the process of excessive abrasion of hard tissues is revealed. Applying the Bernoulli principle to the study of muscles, the ratio of muscle length to its cross-sectional area was expressed mathematically in terms of coefficients. The average values of the coefficients of the same muscles in the control group on the priority and secondary sides differ insignificantly, which indicates a balanced work: the muscles are equally "fast" and equally "strong". Compared to the control group, the first group of patients showed a tendency to a more pronounced difference in the physical qualities of the muscles: strength begins to prevail in some, and speed in others. Clinically, this is manifested at the initial stage of abrasion of hard tooth tissues. A decrease in the temporalis and masseter muscle coefficients in the second group compared to the control group indicates a decrease in muscle length. The gradual increase in the ratios of the wing-shaped lateral muscle from the first to the second group on both the priority and secondary sides of chewing indicates its greater length relative to the cross-sectional area, and therefore, the acquisition of the quality of "speed". In patients of the third group, the difference in the ratio coefficients with the control group and between the priority and balancing sides is more pronounced. Increasingly, the temporalis and masseter muscles acquire the physical quality of "strength", and the wing-like muscles "speed". It is noteworthy that the coefficients of the wing-shaped muscles in patients of the second and third groups on the secondary side are increased compared to the priority side of chewing. Violation of the balance between the physical qualities of the muscles "strength" and "speed" affects the development of pathological tooth abrasion.

Unmixing-based cleaning methods evaluation for re-polychromated plasterwork

The cleaning of re-polychromated plaster is a rather challenging task for Conservators. The optimal choice of solvents and its application instruments may depend on the original polychromy (binder and pigment) that aims to be revealed and the overlay polychromy (binder and pigment) as well. We present a new image-processing based method that uses hyperspectral imaging to obtain a non-invasive quantitative evaluation of cleaning procedures. It is based on the application of unmixing techniques for this problem. The method computes three quality indices: efficiency, destructivity, and alteration, that are based on the residual amounts of overlay pigment, the detection of excessive abrasion in the sample and the change in color that the cleaning produces. It produces as well pixel-by-pixel concentration maps and presence maps for plaster and overlay pigment, and it can self-evaluate by computing the error map comparing the modelled spectral reflectance with the measured spectral reflectance from the samples.

Analysis of Paranet Techniques in Fulfilling National Food Diversification as a Solution to the Highland Water Crisis

<p>The need for food in the industrial world tends to increase every time, this is due to Indonesia's population growth rate continues to increase. This prospect is said to be positive, because it also absorbs the level of sales of local agricultural commodities, so that the level of welfare also increases. UKM XYZ is a social enterprise that was formed together, with the aim of collecting various harvests carried out by farmers, which are then processed into processed food products, so as to increase the cost of added value income. The technique in this activity is carried out manually, with the form of nets used that must cover the plantation area as a whole, without gaps, so that the irrigation process using dew can be carried out perfectly. The results of the water quantity value from the paranet net technique are greater than the quantity value. rain of hope. This makes it an alternative technique that can be adopted by farmers in dealing with climate change or prolonged climate crises such as drought. The results of the production value of the production quantity of the harvest value deposited to SMEs XYZ in the three month period (January – March 2023), show a better increase than the initial data period (October – December 2022). The high water quantity value from the paranet netting technique must be adjusted to the conditions of the slopes or the steepness of agricultural land, so that it does not pose a risk of landslides or excessive abrasion, which is detrimental to farmers</p>

Optimal control of the belt conveyor as part of the technological process of ore mass transportation by controlling the belt tension

Optimum control of the conveyor in the transport flow due to the change of the belt tension is proposed in order to reduce the costs of transporting goods by increasing the life of the belt and reducing energy consumption costs. It is suggested to use tape tension control to eliminate the accidental slippage of the tape on the drum and its excessive abrasion during the transportation of the ore mass. To implement the control method being developed, it is necessary to use a mathe-matical model with distributed parameters, on the basis of which an optimal control model will be formed using the control principles considered in the work. Control of this kind of objects is determined by the technological need to compen-sate for the slippage of the belt on the drive drum of the conveyor, which is based on the process of transmission of motion using friction, and is implemented by changing the thermal field on the arc of the girth by changing the tension of the conveyor belt or the speed of rotation of the drum. Thus, from the point of view of the theory of control of systems with distributed pa-rameters, in the process of controlling the thermal field of the drive drum and belt, the controlled coordinate is the temperature or its distribution on the girth arc. As a result of a change in the circumferential force on the drive drum, the pressure of the tape on the lining of the drum changes, which leads to a change in the value of the heat flow both in terms of amplitude and spatial distribution (the value of the working sliding arc changes, i.e. the area of elastic interaction), which is compensated by con-trolling the tension ribbons

Influence of Dental Students' Dietary Habits on Tooth Color

Objectives: To determine the influence of dental students' dietary habits on tooth color. Materials and Methods: The ethical committee of Mersin University granted permission to conduct the study (number 2022/708). The consent form was approved by all participants. The following exclusion criteria were used for the selection of participants: gingival problems, the presence of excessive abrasion, dental malocclusion, a history of orthodontic or bleaching treatment, caries, and composite fillings on the facial surfaces of the teeth. A questionnaire consisting of 18 questions was directed to 202 students included in the study. The color of the upper central incisors and canines of the participants who completed the questionnaire was measured using a clinical spectrophotometer device(Vita Easyshade V). Tooth color assessment was performed by a calibrated operator. The L*, C*, H*, a*, and b* parameters were recorded. Data were subjected to descriptive statistical analysis, Spearman's rho correlation analysis and multivariate testing. Results: The sample consisted of 202 dentistry students. 96.5% of the participants were between the ages of 18-25 and more than half were female. L*, C*, H*, a*, and b* mean values in canine and incisor teeth did not differ statistically significantly according to age groups(p>0.05). The mean values of C* and b* in canine teeth and the mean values of all parameters except L* in incisor teeth showed significant differences according to gender(p<0.05). Staining beverages in the diet had no effect on L*, C*, H*, a*, and b* parameters of the canine and incisor teeth. A negative correlation was found between the frequency of consuming energy drinks and the L* value in the incisor teeth(r=-0.215; p=0.016). Conclusion: Females have lighter teeth than males. The increase in the amount of consumption of the evaluated staining beverages is one of the factors that cause the tooth colors to become darker and mat.

The die holder interaction variable analysis of 1D2B screw heading machine and its adjustment algorithm design

Die forming is a key process in a production line of metal screw manufacturing, the most commonly used industrial process equipment type is one-die two-blow (1D2B) heading machine. Current solutions for die holder adjustment among manufacturers rely mostly on inheritance of experience. The lack of systemized solutions for fundamental machine tuning causes a gap in technological and intelligent upgrade. This study analyzed the most difficult eccentric tuning of the 1D2B heading machine. The adjustment behaviour of die holder from first blow and second blow were systemized, and the relevant interaction was divided into the following procedures: first die eccentric component adjustment, second die eccentric component adjustment, decoupling of interactions, and precompensation process design. The dimensional differences corresponding to die holder adjustment mechanisms were used to allow operators to implement the adjustments sequentially to complete die holder tuning. This study developed a systemized tuning procedure based on designed algorithm. In the developed procedure, precompensation coupling design was conducted for effectively reducing tuning errors. Tuning based on the proposed procedure enabled the precise adjustment of the die holder positions relative to the eccentric errors of corresponding manufacturing dimensions. The developed procedure can solve the problems of manual trial-and-error operations and excessive abrasion of the die holder resulting from unstable tuning qualities. Key parameters proposed by one type of heading machine, such as equipment die holder’s adjusted pitch, die center distance, and position of the axis of rotation, were examined regarding the proposed adjustments to verify the feasibility of the systemized tuning method.

Application of a Discrete Double-Row Scraper Cleaner as an Efficient Procedure of Cleaning of Belt Conveyors Aimed at Transporting Bulk Materials

We study an actual problem of cleaning of conveyor belts from adhered finely divided materials in the process of operation of belt conveyors. The material remaining on the belts causes numerous problems for the conveyor transport. In the course of time, adhered particles fall into the subconveyor space, thus violating the normal operation of the conveyor. This also leads to rapid failures of the roller supports, excessive abrasion of the working surface of the belt, and hence, to a more rapid wear of the conveyor belt. The procedure of cleaning of the belts enables one to remove the indicated problems. At present, there are various types of available cleaning units. Each of these units has its own advantages and disadvantages. In most cases, this complicates the choice of the required unit. We estimate the efficiency of application of a discrete double-row scraper cleaner of the conveyor belt. Its application increases the degree of cleaning without damaging the surface of the belt due to the presence of a counterbalance clamping attachment.

Identification of Problems Associated with the Usage of Friction (Koeppe) Hoists Based on Geodetic Measurements

The hoist assembly based on the Koeppe friction is a commonly used solution in mining. However, it has some disadvantages. A few centimeters offset of the groove axis can lead to excessive abrasion of linings on the Koeppe friction and pulleys. As a consequence, the mines are forced to bear the direct and indirect costs of replacing the linings such as the cost of materials and service as well as the cost of extended machine and shaft downtime. Last year, the authors undertook a geodetic inventory of the condition of two hoisting machines with a Koeppe winder. Terrestrial laser scanning enhanced with precision total station measurements were performed. Additionally, elements particularly important for the performed analysis (inclination of hoisting machine and rope wheels shafts) were determined by the precision leveling technique. Obtained results were verified using measurements on Szpetkowski’s tribrach. Appropriate selection of the measurement methods in both analyzed examples allowed us to determine the causes of destruction of each hoist assembly component. Based on precise geodetic data, guidelines have been defined for rectification (twisting and shifting the rope pulleys), which seems unavoidable despite the lack of unambiguous legal regulations.

Ceratoplastia lamelar anterior profunda (DALK) como tratamento de úlcera estromal profunda em cão: relato de caso

Characterized by the rupture of the corneal epithelium, corneal ulcers threaten ocular integrity, with multifactorial development, such as decreased protection and excessive abrasion applied to the corneal surface. Keratoplasty restores the corneal anatomy, removing the inflamed or infected tissues, in order to promote visual acuity. The technique of deep anterior lamellar keratoplasty (DALK) selectively removes the diseased layers of the cornea, keeping the Descemet membrane and endothelium healthy, reducing the risk of rejection, aimed at tissue recovery. In the present report, a canine, from the Shih Tzu breed, a female, that has not been castrated, 2 years and 6 months old, was treated, she had a history of ocular discomfort and mucous secretion in both eyes. In the ophthalmic examination, keratoconjunctivitis sicca was found in the left eye and ectopic cilia was found in both eyes. With the aid of a fluorescein test, the presence of a deep stromal ulcer affecting the right eye was confirmed. The patient underwent ectopic cilia removal using the wedge resection technique and an allogeneic corneal transplantation using DALK, with only the diseased epithelium and stroma being replaced, reducing the risk of rejection and failures related to surgery. 90 days after the procedure, there was no reaction to the graft, there was complete epithelial repair and maintenance of visual function with slight corneal opacity. &nbsp

Investigation of the effect of Cr2O3-2 % TiO2 coating on braking performance

The brake discs of the new generation vehicles operate with very high speed and tough braking conditions. Therefore, high performance in braking is essential in terms of human and vehicle safety. In vehicles, the braking performance criterion is to control the speed of the vehicle safely without causing a mechanical failure. During a braking process in a moving vehicle, an excessive abrasion occurs. The aim of this study was to investigate the performance of the brake disc coated with Cr2O3-2%TiO2 (Metco106F) composite powder by using the plasma coating method to increase the abrasion resistance of automobile brake disc. The braking test was performed according to the SAEJ2430 braking test standard. The microstructure, hardness, wear and braking performance characteristics of the coating were investigated. Our results showed that the coated disc exhibited better wear resistance than the uncoated disc under the different wear mechanisms at high temperatures. The obtained coefficient of friction revealed that the coated disc showed better braking performance.

Deep drawing of polymer coated metal sheets

In the present study, the deep drawing of polymer coated metallic sheets were experimentally investigated to reduce friction and increase manufacturing efficiency without using a lubricant. Coating of metal sheets with a polymer material before the deep drawing process provides numerous other advantages such as long service life, decorative appearance, corrosion protection, prevention of excessive abrasion. In the experiments, deep drawing ratio, blank holder pressure, and punch speed parameters were varied at various intervals and the obtained values were evaluated via graphs. Experiments of the uncoated metal sheets were conducted as well as the coated ones to compare the results. Results of this study showed that the polymer coating improved the surface quality of the test specimens. As a result of this improvement; the average molding forces decreased, obtained deep drawing ratios increased and defects such as tearing and wrinkling were alleviated by coating metal sheets with polymer material compared to uncoated sheets.

SPIELBERGER STATE-TRAIT ANXIETY INVENTORY FOR PATIENTS WITH EXCESSIVE TOOTH ABRASION AND TEMPOROMANDIBULAR DISORDERS

Hypertonia and parafunction of masticatory muscles (bruxism), which cause prolonged non-functional sliding movements of the mandible against the maxilla with teeth closed, contribute to the development of functional overload. Increased activity of masticatory muscles may occur due to the agitation of the central nervous system. On the periphery, its action manifests itself in the form of dysfunctions and bruxism, which leads to fatigue in the masticatory muscles, their spasm and the development of symptoms of the pain dysfunction syndrome. There is also an inverse relationship between local disturbances of occlusion and the development of stress. This case occurs, because in stress situations the adaptive capacity for local disturbances of the motor part of the masticatory system, including the disturbances of occlusion, is reduced. This causes a motor reaction in the form of dysfunctions of closing masticatory apparatus, which, in long-term stressful situations, can turn into well-established habits. This explains the appearance of pain symptoms of dysfunction in stressful situations. Consequently, there is convincing evidence that psychological and psychosocial factors play an important role in understanding the TMDs, but there is no conclusive evidence that these factors are etiologic ones.
 The purpose of the study is to determine personal and situational anxiety in patients with excessive tooth abrasion alone and those with both excessive tooth abrasion and temporomandibular disorders, comparing them with each other.
 Materials and Methods. 68 patients were included in the study, 31 (45.6%) included male and 37 (54.4%) contained female patients aged 21 to 70. Studied patients were divided into two groups: the control group and the study group. The control group included 31 patients diagnosed only with excessive tooth abrasion in combination with possible other occlusal disorders. The study group included 37 patients with excessive tooth abrasion, possibly with other occlusal disorders and various forms of temporomandibular disorders: muscle, articular, and combined. The study was conducted individually using the Spielberger State-Trait Anxiety Inventory (STAI), which included instructions and 40 questions, 20 of which were designed to assess the level of situational anxiety (SA) and 20 – to assess the level of personal anxiety (PA). Online questionnaire at: http://psytests.org/psystate/spielberger-run.html was used for automatic data processing of Spielberger psychological evaluation of patients.
 Results. A high level of personal anxiety was observed in patients of the study group with both excessive tooth abrasion and TMDs, in comparison with patients in the control group (48.6% of patients in the study group vs. 0% in the control group), p<0.001.
 Furthermore, a significant prevalence of patients with a high level of situational anxiety was determined among the patients in the study group with excessive tooth abrasion and TMDs, in comparison with patients in the control group with excessive tooth abrasion alone (64.0% in the study group vs. 3.2% in the control group, p<0.001). Thus, statistically significant signs of a high level of personal and situational anxiety were found among patients with excessive tooth abrasion and present temporomandibular disorders in comparison with patients who have only excessive tooth abrasion.

CFD Modelling of Coupled Heat Transfer between Solid and Fluid in a Twin Screw Compressor

Temperature variation in a compressor is very critical for compression performance and efficiency. To accurately predict the thermal dynamic behaviour of a compressor, heat transfer between metal components and the working fluid needs to be properly evaluated in CFD simulation. Thermal expansion of solid components due to temperature increase may also cause excessive abrasion of metal parts and changing in leakage clearance. Solving conjugate heat transfer (CHT) of twin screw compressors not only needs to deal with complex moving rotor geometry, but also needs to consider huge difference of temperature propagation time scale inside different media. Typically, heat propagation is much slower in solid than in compressed gas. Therefore, it may take many compressor revolutions to reach a stable CHT solution if heat conduction inside solid and thermodynamic temperature change of compressed gas are directly coupled in a CFD simulation. The run time of simulation may become impractical.In this paper, an innovative approach solving conjugate heat transfer using the Mixed Timescale Coupling method between different media will be described in detail. This approach can address time scale difference in heat propagation. The proposed approach will be applied to a twin screw compressor. Simulation results will be compared with available test data. Effects of conjugate heat transfer will be evaluated by comparing the simulation results for the cases with and without considering conjugate heat transfer. Thermal expansion of the solid rotor will also be evaluated using predicted temperature distribution. Simulation will also demonstrate that the approaches used in the paper are robust, fast, and user friendly, and can be readily applied to industrial compressor systems.

Failure analysis of the clay extruder nozzle Souza MSL-320 of Ladrillera Ocaña

This work presents a failure analysis performed on a clay extruder nozzle used in a brick factory in order to observe if the material is suitable to withstand the conditions to which it is exposed. The extruder nozzle responsible for shaping the ceramic blocks had wear generated by excessive abrasion, thus increasing production costs. A methodology was designed to determine the cause of failure and propose the appropriate material for the nozzle through a study based on forensic engineering. Samples of the clay paste and the nozzle material were selected, which were characterized physically and chemically by hardness tests, metallography, spectrometry, X-ray diffraction, and scanning electron microscopy.

CLINICAL EVALUATION OF THE DENTOALVEOLAR SYSTEM IN EXCESSIVE TOOTH ABRASION AND TEMPOROMANDIBULAR DISORDERS

The purpose of the study was to determine the features of the state of the dentoalveolar system in patients with excessive abrasion of teeth with and without temporomandibular disorders (TMDs) in a comparative aspect.
 The study group included 68 patients, 31 (45.6%) of which were males and 37 (54.4%) females, aged from 21 to 70.
 Patients are divided into two groups: the control group and the study group. The control group included 31 patients who were diagnosed with excessive tooth abrasion alone in combination with possible other occlusal disorders. The study group included 37 patients with excessive abrasion of teeth, possible other occlusal disorders and various forms of temporomandibular disorders: muscular, articular, and combined.
 A preliminary clinical dental examination was based on instant diagnosis according to Hamburg protocol.
 Additional examination methods included clinical diagnostic techniques (to determine features of the mandibular movements, loading tests of the TMJ, palpation of masticatory muscles, muscles of the neck and shoulders, etc.), as well as imaging techniques of the TMJ (panoramic radiography, zonography, 3D radiography of the TMJ, MRI, ultrasound of the TMJ and muscles), as well as the condylography.
 The comparative analysis of prosthetic pathology, which was revealed in the oral cavity of patients depending on the groups, showed the following data.
 Excessive tooth abrasion without other occlusal pathologies was diagnosed only in 3 of 31 patients accounting for 9.7% in the group of patients with excessive tooth abrasion without signs of TMDs (control group).
 Among patients in this group, a fairly high percentage is attributed to the pathological eruption of the third molars – 32.1% and "multiple dental defects" – 21.5%, which together account for 53.6%.
 Excessive tooth abrasion alone without other occlusal disorders was diagnosed in 6 of 37 patients accounting for 16.2% in the group with both excessive tooth abrasion and temporomandibular disorders (study group).
 Prosthetic pathology was determined to occur three times more often among patients with both excessive tooth abrasion and TMDs compared to the patients with excessive tooth abrasion alone (38.7% in the group with TMDs vs. 14.3% in the control group, p<0.01). However, the pathological eruption of the third molars, on the contrary, was detected 2 times more often in the group with excessive tooth abrasion alone compared with the group of patients with TMDs (32.1% in the control group vs. 16.1% in the study group, p<0.05).
 A homogeneous distribution of the generalized type of tooth abrasion and its local type was found to be specific to the controls (51.6% with the generalized type and 49.4% with the local type of abrasion).
 However, for the local type of abrasion in this group of patients, it was determined that a significant predominance was specific to the frontal area in comparison with the distal regions of the tooth abrasion (the rates reached 41.9% for the frontal area vs. only 6.5% for the distal regions; p<0.01).
 A significant predominance of the local type of excessive abrasion (83.7% of the local type vs. 16.3% of the generalized type, p<0.001) was determined in patients with both excessive tooth abrasion and TMDs. Moreover, the distribution was almost homogeneous in relation to the frontal or distal regions (43.2% for frontal and 40.5% for distal areas).
 Probably, the loss of distal occlusal support in the area of the lateral teeth is a factor that can provoke the development of TMD. Such features should be taken into account when providing prosthetic care to such patients.
 The revealed features in the diagnosis of patients with excessive tooth abrasion, other occlusal disorders in the settings of temporomandibular disorders should be taken into account in their treatment and, especially, in the provision of prosthetics to such patients.

Комплексна ортопедична стоматологічна реабілітація хворих з посиленим стиранням зубів і скронево-нижньощелепними розладами

Комплексна ортопедична стоматологічна реабілітація хворих з посиленим стиранням зубів і скронево-нижньощелепними розладами

A new suoid with tubulidentate, hypselorhizic cheek teeth from the early Miocene of Córcoles, Spain

Excavations at Córcoles, Guadalajara, Spain (MN 4) in October 1987, yielded a mandible and several isolated teeth of a strange suiform with tubulidentate cheek teeth, initially interpreted to be the remains of Tubulidentata. The specimens are complete enough to remove any doubt about which Order (Artiodactyla) and Superfamily (Suoidea) they belong to. They are here attributed to the Family Doliochoeridae, being related to the genera Bransatochoerus (MP 30) and Lorancahyus (MN 2) both of which have hypsorhizic cheek teeth, the latter with tubules in the teeth, but not to the fully-expressed extent seen in the fossils from Córcoles and the molars retain a distinct and large pulp cavity, which is absent in the Córcoles species. It is inferred that these suoids comprise an evolutionary lineage which went extinct in the early Miocene (ca MN 4b or MN 5) and that the dental specialisations imply ingestion of food to which soil was adhering, which caused excessive abrasion of the teeth, not only occlusally, but also on the lingual aspects of the cheek teeth. Examination of the occlusal and lingual surfaces of the teeth con?rm the presence of many pits and large scratches on them, in contrast to the buccal and distal surfaces of the teeth which have few scratches or none, respectively.

ANALYSIS OF PATIENTS’ EXAMINATION WITH UNSATISFACTORY ORTHOPEDIC TREATMENT RESULTS OF HARD TISSUES OF TEETH AND DENTAL ROWS OF NON-REMOVABLE DENTURES

Nowadays, the problem of prosthetic with non-removable orthopedic structures is quite common and is widely described in domestic and foreign literature. Prosthetics of non-removable structures of prosthetics has a number of advantages: complete rehabilitation of biting function, chewing efficiency, aesthetic norm of a smile. Invisible prosthesis designs, usually small in size, have a short period of psychological and physiological adaptation, which has a good reflection on their long-term use by the patient.
 The examination of dental patients in the clinic of orthopedic dentistry with unsatisfactory results of prosthetic dentures after 5 years with orthopedic treatment allowed to highlight the main indicators of inapplicability regarding the further use of dentures in terms of biocompatibility, mechanical strength and aesthetic properties.
 The main aim of the study was to improve the quality of patients’ treatment by identifying the causes of treatment complications by an orthopedist using the method of comparative analysis during the examination of patients with unsatisfactory results of dentures using permanent dentures.
 To identify the causes of complications of orthopedic treatment, a clinical examination of patients with unsatisfactory results of treatment with permanent constructions of dentures on a cast base was performed. The criteria for evaluation were the following indicators: bad breath, gums pain and bleeding, pain and mobility of the supporting teeth, pain under the intermediate part, metallic taste, pain in the blood vessel, darkening of the lining, chipping the lining, obscuring gums, excessive abrasion, and cleavage. From anamnesis and records in the history of the disease, the period of difficulty was determined.
 Our research results indicate that a significant part of ineffective treatment is due to the wrong choice of auxiliary and structural materials. Given that the choice of materials is performed arbitrarily, in almost half of cases, taking into account the wishes of patients and their financial capabilities, including the physical, mechanical and clinical and technological characteristics of dental materials, in our opinion, it is necessary to create a computer model of rational choice of material, therapeutic and prophylactic measures to improve the effectiveness of orthopedic treatment for patients with defects in hard tissues of teeth and dentition with non-removable structures.
 The complex of the following studies will allow the orthopedic dentist to continue improving the quality of patients’ treatment at the clinical stages of treatment with non-removable dentures.