[Brief Analysis of Clinical Evaluation Concerns of Personalized Abutments and Abutment Crown Bridge Products].

Objective: The applications of personalized abutments and abutment crown bridge products have increased year by year, but there is no clear requirement for clinical evaluation of the same variety of such products. This study mainly introduces the clinical evaluation concerns of personalized abutments and abutment crown bridge products, in order to provide reference for the declaration and registration of such products. Methods: The clinical evaluation of personalized abutments and crown bridge products are summarized, and the research content of clinical evaluation is clarified. Results: The clinical evaluation requirements that need to be considered by enterprises are introduced. Conclusion: Personalized abutment and abutment crown bridge products can refer to this study when they are launched in China, mainly using in vitro performance comparison tests for equivalence verification.

Japanese Wooden Plate Denture as Origin of Suction Retention.

The modern theory of complete denture retention using suction was applied to wooden plate dentures in Japan from the first half of the 16th century, which is an astonishing achievement since it was clinically applied in North America and Europe in the latter half of the 19th century nearly 300 years later. Wooden dentures are unique to Japan resulting from skilled Japanese craftsmanship and are not found in other countries. We comprehensively reviewed reports on wooden plate dentures, analyzed 145 complete and partial dentures, and discussed their history. Japanese wooden plate dentures are mainly made of box wood, and artificial teeth are made of pagodite, ivory, and natural teeth. Small nails were driven into the molar region. Many existing dentures revealed attrition on the occlusal faces, thereby indicating that the wearers were able to masticate sufficiently. Wooden plate dentures have been used for 400 years in the early 20th century. Although Japanese wooden dentures have not been mentioned in the history of dentistry in Western literature, they comprise an important part of the history of denture development.

Behaviors, hygiene habits, and sources of care among removable complete and partial dentures wearers: A multicenter cross-sectional study.

OBJECTIVES: There is a lack of data regarding the hygiene practices and sources of care among individuals in Yemen who wear removable complete and partial dentures. The purpose of this study was to explore the behaviors, hygiene habits, and sources of care information among patients who utilize complete and partial dentures in Yemen. MATERIALS AND METHODS: A descriptive cross-sectional research design was utilized, and a sample of 217 consecutive participants who wore removable complete and/or partial dentures were enlisted. A questionnaire was employed to collect data on demographic information, educational attainment, denture habits, denture cleaning practices, and encountered difficulties. Statistical analysis was conducted using SPSS software, and significance was determined using chi-square tests, with a significance level of .05. RESULTS: The data analysis revealed that a majority of the participants were male (72.4%) and had an average age of 65.14 years. Fifty-three percent of the participants wore partial dentures, while 34.6% wore complete dentures. Only 6.5% of the participants wore both complete and partial dentures, and 6% wore overdentures. The majority of participants (88.47%) had dentures made of acrylic material. Additionally, 43% of participants wore dentures while sleeping, and 61.3% stored their dentures in dry places without a water-filled container when not in use. The most commonly reported cleaning methods were water only (24.4%), followed by water and soap (19.4%). Furthermore, a large portion of the participants (59.4%) received denture care information from dentists. However, the majority (59%) did not visit a dentist for regular denture maintenance or any denture-related issues. The data analysis did not reveal any significant association between age or education level and denture cleaning methods. CONCLUSION: This cross-sectional survey provides insight into the hygiene knowledge and practices of removable denture wearers in Yemen. The findings underscore the necessity for enhanced oral hygiene education and awareness within this population. The study offers valuable insights for oral health professionals to design targeted interventions and educational initiatives aimed at promoting proper denture care and maintenance. These efforts have the potential to enhance the oral health and overall well-being of removable denture wearers.

Evaluation and assessment of the wettabilty and water contact angle of modified poly methyl methacrylate denture base materials against PEEK in cast partial denture framework: an in vitro study.

INTRODUCTION: The prevalence of adults with partially dental arches is expected to be more than imagined and patients requiring replacement of missing teeth are slowly increasing in number too. Removable partial dentures are known to provide for substantial replacement for the missing teeth with also added advantages when compared to fixed or implant prosthesis, mainly in elderly patients. Denture base material performance and durability are greatly influenced by wettability and water contact angle. In the case of dentures; adequate moisture distribution is necessary to ensure excellent wettability which has an influence on comfort and oral health. The purpose of conducting this study was to find out whether the advancements made using PEEK (Polyether ether ketone) would prove to be more beneficial than the current upgrades in the current material spectrum. MATERIALS AND METHODS: This study was performed under in vitro conditions. All the fabrication and processing was done only by one operator. The materials used were divided into three groups each comprising 20 samples. Group A was modified polymethylmethacrylate (Bredent Polyan), Group B was polyoxymethylene acetal resin (Biodentaplast) and Group C was PEEK. An Ossila Goniometer was used to measure the contact angle. The three types of liquids used for the testing included distilled water, natural saliva and mouth wetting solution (Wet Mouth Liquid, ICPA India). Human saliva was collected from an individual with no medical conditions and normal salivary secretion. RESULTS: The data was analyzed using One-way ANOVA test and a pairwise comparison using the Post Hoc Tukey's Honest Significant Difference. Table 1 consists of the mean water contact angles of the denture base materials and mean contact angles of various denture base materials. In saliva, mouth wetting solution and distilled water, the highest mean and least mean contact angle was seen in Polyan and Biodentaplast respectively. A signicant difference was seen between PEEK and Polyan and Biodentaplast and Polyan on further comparison. CONCLUSION: From the resources and the materials at our disposal, it could be concluded that Polyan, Biodentaplast and PEEK and could be used as viable options in cast partial denture framework.

An in vitro assessment of optimizing implant positions in bilateral distal extension implant-assisted removable partial dentures: A microstress analysis.

AIM: The aim of this study was to analyze and compare the stress distribution on dental implants in various positions when used with implant-assisted removable partial dentures. SETTINGS AND DESIGN: This was an in vitro study. MATERIALS AND METHODS: A model representing a mandibular bilateral partially edentulous condition, with missing premolars and molars, was fabricated using epoxy resin. Two implants of similar diameter measuring 4.0 mm × 10 mm (Dentium, Korea) were inserted in the second molar and the second premolar region on either side of the model for comparing the biomechanical effect of various implant locations. Two types of loads 100N and 125N were applied vertically using universal testing machines in the premolar and molar regions. The loads on the implants beneath the cast partial denture were measured by physical stress analysis using a microstrain gauge. STATISTICAL ANALYSIS USED: A comparison of maximum stress observed at the premolar versus molar regions due to the application of the 100N and 125N loads was done using the Mann-Whitney U-test. RESULTS: In physical stress analysis, obtained results were statistically analyzed, and the result was statistically not significant (P = 0.435 at 100N and P = 0.718 at 125N) in positional changes of implant. CONCLUSION: In the current study, the statistical analysis of physical stress revealed no significant differences in stress values between the loadings at the premolar and molar regions. This suggests that the implant can be placed in either the premolar or molar region based on the availability of bone without affecting stress distribution.

Accuracy and surface roughness of Co-Cr partial denture frameworks with different digital fabrication methods.

STATEMENT OF PROBLEM: Traditional removable partial denture (RPD) manufacture is being phased out in favor of computer-aided design and computer-aided manufacturing (CAD-CAM) techniques and rapid prototyping (RP), which provide more efficient methods of producing RPD frameworks. However, studies comparing the accuracy and surface roughness of these approaches on RPD frameworks are still scarce. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy and surface roughness of class I cobalt chromium (Co-Cr) removable partial denture frameworks digitally constructed using 2 different CAD-CAM technologies: direct milling (DM) and selective laser melting (SLM). MATERIAL AND METHODS: An educational maxillary stone cast was scanned to create a resin model after rest seat preparation. The resin model was scanned, and an RPD framework was digitally designed. Sixteen frameworks were constructed (n=8). Two groups were defined. In the direct milling (DM) group, the standard tessellation language (STL) file of the RPD framework was used to mill the design from a Co-Cr blank directly. In the selective laser melting (SLM) group, the STL file of the RPD framework was used to print the design from Co-Cr powder using the selective laser melting technique. Geomagic Control X software program was used to measure the accuracy of the fabricated frameworks. Surface roughness was tested using optical profilometry. An unpaired t test was used to compare the 2 groups (α=.05). RESULTS: The DM group showed significantly higher mean ±standard deviation accuracy (189 ±9 µm) (P<.001) compared with the SLM group (456 ±122 µm). Regarding the surface roughness, the DM group (0.157 ±0.001 mm) showed significantly lower surface roughness (P<.001) compared with the SLM group (0.256 ±0.001 mm). CONCLUSIONS: The direct milling fabrication technique enabled the fabrication of Co-Cr RPD frameworks with higher accuracy and less surface roughness when compared with the 3-dimensionally printed SLM technique.

Binary Logistic Regression Analysis on the Association of Occlusion with the Temporomandibular Joint Arthralgia in the Partial Denture Wearers-A Retrospective Study.

PURPOSE: To analyze the potential association between the occlusion features and the incidence of temporomandibular joint (TMJ) arthralgia in patients with partial dentures. MATERIALS AND METHODS: A total of 101 partial denture wearers were collected, 45 with unilateral TMJ arthralgia diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Binary logistic regression analysis was adopted. The TMJ asymptomatic group (n = 45) was quantified as 0, while the TMJ arthralgia group (n = 56) was quantified as 1. In total, 13 occlusion variables were analyzed: gender, age, number of prosthetic teeth, number of dentition quadrants with a prosthetic tooth, anterior or posterior prosthesis location in maxillary or mandibular dentition, occluded prosthesis pair, anterior overjet, and overbite relation. Simple and multiple binary logistic models were adopted, accordingly, for the risk impact of them on TMJ arthralgia. RESULTS: Overbite (OR = 2.238) and maxillary anterior prosthesis (OR = 0.305) were entered into the simple binary logistic model; while overbite (OR = 2.774) plus maxillary anterior prosthesis (OR = 0.347), overbite (OR = 3.425) plus unilateral maxillary posterior prosthesis (OR = 4.672), and overbite (OR = 3.476) plus overjet (OR = 0.436) and mandibular anterior prosthesis (OR = 0.177) were entered into the multivariate logistic regression model (all, P < .05). CONCLUSIONS: Partial denture wearers with a deep overbite, especially those with a unilateral maxillary posterior prosthesis, had a higher prevalence of unilateral TMJ arthralgia.

[Protocol for teeth set-up in full denture without the use of wax rims and its theoretical justification]. / Protokol postanovki iskusstvennykh zubov bez ispol'zovaniya prikusnykh valikov i ego teoreticheskoe obosnovanie.

OBJECTIVE: To develop a protocol for setting artificial teeth in a complete removable denture without landmarks on the bite ridges. MATERIAL AND METHODS: Based on the analysis of the literature of various areas of dentistry and the clinical experience of doctors corresponding to each of the disciplines of the specialty, a protocol for setting teeth in a full prosthesis was developed and its theoretical justification was given. RESULTS: Using the method proposed by us, 324 prostheses were made for 162 patients with complete secondary adentia of two jaws. A clinical study and comparison with the generally accepted method of manufacturing prostheses using wax rollers was carried out. The method proposed by us showed greater efficiency based on a comparison of the results of functional tests after prosthetics. CONCLUSION: The described method is part of the concept of manufacturing a functional prosthesis, is used in removable prosthetics, but can also be used in non-removable prosthetics, allows highly accurate, in accordance with individual anatomical parameters and features, to restore the occlusion of the patient during the reconstruction of the dentition, taking into account individual anatomical and functional parameters.

New Methods for Replacing Single Missing Teeth with Non-prep Bridges (NPBs) - A Case Series.

PURPOSE: Newly developed non-invasive methods for replace a missing tooth and closing single-tooth gaps in the poster- ior region using resin composite are presented. MATERIALS AND METHODS: Four different non-invasive methods and the technical procedures, materials and instruments used are presented in a case series. These include the direct intraoral insertion of composite (with and without individual shaping aids) and indirect restorations, which are fabricated conventionally or digitally and bonded. RESULTS: The case series showed that all four methods can be used to replace single missing teeth in the posterior region, meeting current clinical requirements. Particular attention was paid to the design of the pontics, the dimension of the connector area, firm proximal contacts to the adjacent teeth, hygiene, and appearance of the non-prep bridges (NPBs). The advantages and disadvantages for both the direct and indirect techniques illustrated in this case series were com- pared in detail. CONCLUSIONS: Several direct and indirect non-invasive methods for single-tooth replacement are available today. Although the evidence is still limited, there is a potential for frugal dental interventions with NPBs. Further experimental and clinical studies are necessary to demonstrate that they reliably meet quality requirements (including sufficient survival rates), satisfy the criteria of cost-effectiveness (compared to treatment alternatives) and that there is a demand from the population.

Effect of various printing parameters on the accuracy (trueness and precision) of 3D-printed partial denture framework.

OBJECTIVES: To measure and compare the accuracy of 3D-printed materials used for RPD production to improve workflow and eliminate errors in manufacturing. METHODS: A partially edentulous maxilla (Kennedy Class III, modification 1) was prepared and designed with proximal plates, rest seats and clasps in one first premolar, one canine and two second molars. A total of 540 3D printed RPD frameworks were 3D printed with three different types of resin (DentaCAST (Asiga, Australia), SuperCAST (Asiga, Australia) and NextDent (3D Systems, Netherlands)). To evaluate the trueness of the printing materials, they were printed with three types of layer thickness: 50 µm, 75 µm and 100 µm, using two types of build angles: 0° and 45° and three types of plate locations: side, middle and corner. After production, all specimens were scanned and superimposed with a control sample that was digitally designed. Using the initial alignment and best-fit alignment method, the root mean square error (RMSE) was calculated. To capture region specific discrepancy, 10 points of XYZ internal discrepancy within RPDs were measured and Euclidean error was calculated. Data was statistically analysed using Shapiro-Wilk and Kruskal-Wallis tests, one-way ANOVA and T-test (SPSS Version 29) and MATLAB (R2022b). RESULTS: Optimal results were found using 45°, middle of the build plate and layer thicknesses of 100 µm (115 ± 19 µm, DentaCAST), 75 µm (143 ± 14 µm, NextDent), 50 µm (98 ± 35 µm, SuperCAST), which were clinically acceptable. Results were statistically significant when comparing layer thickness in each testing group (p < 0.001). Layer thickness was a primary parameter in the determination of print accuracy among all materials (p < 0.001). Higher discrepancies and failures were observed in 0° prints. No statistically significant difference was found in material usage between build angles or layer thickness (p > 0.005). CONCLUSIONS: All three 3D printing materials exhibited clinically acceptable RMSE results with a build angle of 45° with a printing layer thickness of 50 µm for SuperCAST, 75 µm NextDent and 100 µm for DentaCAST. The highest discrepancies were mostly found in posterior clasps, while the lowest discrepancy was found in palatal straps. Despite unoptimized spacing of prints, frameworks configured to print in the middle of the build plate result in the least printing failures.

Denture tracker for edentulous Alzheimer's patients.

Dementia in Alzheimer's disease complicates the caregivers in tracking the patients. Many options are discussed in the literature. A novel technique is essential to improve the quality of life and to assist in locating the patients. The Global Position System (GPS) trackers are attached to dentures and the movements are observed through a mobile application. This technique discusses on a simple method of tracking Alzheimer's edentulous patients with the support of removable dentures. Denture tracking devices are a secured form of tracking patients. A GPS device in dentures assists in locating the patient's movement and supports the caretakers.

Viral contamination of acrylic resin removable denture bases in patients with COVID-19: A cross-sectional study.

STATEMENT OF PROBLEM: Salivary gland ducts are one of the primary targets of severe acute respiratory syndrome coronavirus 2. Moreover, saliva contains minor and major salivary gland secretions and a combination of nasopharyngeal and lung secretions. The acrylic resin bases of complete or partial removable dentures have pores and provide a favorable environment for the growth of microorganisms. PURPOSE: The purpose of this cross-sectional study was to investigate the presence of viral contamination of acrylic resin removable denture bases in patients with coronavirus disease 2019 (COVID-19). MATERIAL AND METHODS: The acrylic resin denture bases (partial and complete) of 29 patients with COVID-19 who underwent treatment in the Infectious Diseases Department of Razi Hospital in Ghaemshahr, Mazandaran, Iran, were evaluated. Samples were collected from the intaglio surface of the prostheses by direct swabbing and coding and were evaluated in a laboratory for the presence or absence of coronavirus. The relationship between hospital polymerase chain reaction (PCR) and denture PCR and the relationship between denture type and denture PCR were evaluated with the Fisher exact test (α=.05). RESULTS: Twenty-nine patients, age range 55 to 85 years, 18 women, 3 with partial dentures and 26 with complete dentures, were evaluated. The hospital PCR test was positive in 28 patients, while the denture PCR test was positive in 4 patients. No significant relationship was observed between the results of hospital PCR and denture PCR in patients with COVID-19 (P=.138). All 4 patients who tested positive for denture PCR had complete dentures. No significant relationship was found between denture type and denture PCR test results in patients with COVID-19 (P>999). CONCLUSIONS: Despite the microporous structure of the acrylic resin base, no statistically significant viral contamination was observed.

Performance of complete dentures fabricated with the simplified and the traditional technique: A randomized clinical trial.

STATEMENT OF PROBLEM: The simplified technique has been recommended for the fabrication of removable complete dentures. However, a consensus regarding the performance of the simplified and the traditional techniques is lacking. PURPOSE: The purpose of this randomized clinical trial was to compare the performance of prostheses fabricated with the simplified and the traditional techniques. MATERIAL AND METHODS: Sixty participants were recruited and randomized into 2 groups: traditional technique (control group) and simplified technique (experimental group). The assessments were performed before treatment (baseline) and 2 and 4 months after adaptation to the new complete dentures. The variables evaluated were satisfaction, oral health-related quality of life (OHRQoL) by using the Brazilian version of the OHIP-EDENT, the quality of the prostheses, and, for the functional assessment, the masticatory performance and swallowing threshold. The data were analyzed by the Fisher exact test, the Mann-Whitney test, and the generalized equations estimating (GEE) method. RESULTS: At baseline, the mean ±standard deviation quality of the prostheses was 5.3 ±2.3 for the traditional technique and 4.9 ±2.3 for the simplified technique, and at 4 months, it was 9.3 ±0.9 and 9.1 ±0.9, respectively. For masticatory performance, the mean ±standard deviation X50 at baseline was 5.7 ±1.4 for the traditional technique and 5.7 ±0.9 for the simplified technique, and at 4 months, it was 3.8 ±1.2 and 3.7 ±0.9, respectively. The mean ±standard deviation OHRQoL at baseline was 14.1 ±8.6 for the traditional technique and 12.5 ±9.4 for the simplified technique, and at 4 months, it was 3.2 ±4.3 and 2.6 ±5.1, respectively. The mean ±standard deviation satisfaction at baseline was 9.5 ±3.9 for the traditional technique and 9.3 ±4.2 for the simplified technique; after 4 months, it was 14.8 ±2.0 for both techniques. There was a significant improvement (P<.05) for all variables in the study when comparing them at the baseline to those at the evaluation after provision of new complete dentures. There was no significant difference in all analyzed variables (P>.05) between the 2 techniques for prosthesis fabrication. CONCLUSIONS: The simplified technique appears to be a suitable alternative to the traditional technique for the fabrication of complete dentures, with similar performance.

Use of zirconia onlays in a maxillary removable implant-supported denture: A clinical report.

A common complication with the use of acrylic resin denture teeth is wear of the occlusal surfaces. Modifying the occlusal surfaces with gold onlays has been suggested to combat this phenomenon. This clinical report describes the use of zirconia as an alternative material on a patient with increased tendencies for occlusal wear. The advantages of using zirconia include wear resistance, decreased cost, and straightforward fabrication.

The effect of different framework's material on strain induced in distal abutment in mandibular Kennedy's class II: an in-vitro study / O efeito de diferentes materiais de estrutura na deformação induzida na distal do pilar da classe II de Kennedy mandibular: um estudo in vitro

Objective: This study aims to compare the strain induced in the supporting structures of unilateral mandibular removable partial denture frameworks retained by extra-coronal attachments fabricated with three different materials. Material and Methods: Three mandibular class II digitally designed and printed acrylic models with detachable abutments were used to fabricate three removable partial denture framework with extra coronal attachments from three different materials. A total of 33 models were prepared for strain testing (n=11). Models were divided into three groups according to framework's material: porcelain fused to cobalt chromium (PFM), polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) group. Unilateral load of 60 N was applied in the three groups and strains were measured around the main abutment and saddle area using strain gauge. Results: Statistical analysis was performed using Shapiro-Wilk's test and by checking data distribution. Data were found to be non-parametric and were analysed using Kruskal-Wallis test followed by Dunn's post hoc test with Bonferroni correction. PFM group showed significantly the highest strain values around abutment, slot 1 (1mm distal to the socket of the last abutment) and slot 2 (1 cm away from slot 1) respectively (843.00±23.08, 91.00±6.52 and 1274.00±65.71) than the other tested groups (p<0.05) at same tested sites respectively followed by PEKK group (384.00±37.48, 81.00±2.24 and 135.00±0.00) and PEEK group (29.00±4.18, 63.00±4.47 and 52.00±5.70). Conclusions: PEEK and PEKK for partial denture framework with extra coronal attachments are adequate alternative to PFM due to their good mechanical response applying less strain on supportive structures in free-end cases. PEEK induces lower strain magnitude on the supporting structures when compared to PEKK. (AU)

Objetivo: Este estudo tem como objetivo comparar a tensão induzida nas estruturas de suporte de estruturas de próteses parciais removíveis mandibulares unilateraisretidas por encaixes extracoronários fabricados com três materiais diferentes. Material e Métodos: Três modelos mandibulares de classe II digitalmente projetados e impressos em acrílico com pilares destacáveis foram usados para fabricar três estruturas de próteses parciais removíveis com encaixes extracoronários de três materiais diferentes. Um total de 33 modelos foram preparados para testes de deformação (n=11). Os modelos foram divididos em três grupos de acordo com o material da estrutura: porcelana fundida com cobalto-cromo (PFM), poliétercetonacetona (PEKK) e polieteretercetona (PEEK). Carga unilateral de 60 N foi aplicada nos três grupos e as deformações foram medidas em torno do pilar principal e área de sela usando medido de tensão. Resultados: A análise estatística foi realizada por meio do teste de Shapiro-Wilk e com a verificação da distribuição dos dados. Os dados mostraram-se não paramétricos e foram analisados pelo teste de Kruskal-Wallis seguido pelo de Dunn com correção de Bonferroni. O grupo PFM mostrou significativamente os maiores valores de tensão ao redor do pilar, slot 1 (1mm distal do último pilar) e slot 2 (1 cm de distância do slot 1) respectivamente (843,00±23,08, 91,00±6,52 e 1274,00±65,71) do que os outros grupos testados (p<0,05) nos mesmos locais testados, respectivamente, seguido pelo grupo PEKK (384,00±37,48, 81,00±2,24 e 135,00±0,00) e grupo PEEK (29,00±4,18, 63,00±4,47 e 52,00±5,70). Conclusão: PEEK e PEKK para estrutura de prótese parcial com encaixes extracoronários são alternativas adequadas ao PFM devido à sua boa resposta mecânica aplicando menos tensão nas estruturas de suporte em casos de extremidade livre. O PEEK induz menor magnitude de deformação nas estruturas de suporte quando comparado ao PEKK (AU)

Effects of wearing removable dentures and aging on palatal mucosa blood flow by laser doppler.

Aim: The purpose of this work is to analyze the effects of removable dental prostheses and aging on blood microcirculation in the palatal mucosa. Settings and Design: Blood flow was measured in two groups using the Laser Doppler Flowmeter at three specific anatomical sites: Retro incisive papilla, medial raphe, and Schroeder area. Materials and Methods: Group 1 included young, healthy dentulous individuals (mean age: 23 ± 3 years), and Group 2 contained elderly edentulous individuals (mean age: 62 ± 11.69 years). For Group 1, measurements were taken in a single session; for Group 2, the measurements were taken in two sessions: The first just before the prosthetic load (E1) and again 1 week after new dentures were provider (E2). Statistical Analysis Used: Statistical analyses were performed using SAS software, Version 9.4 of the SAS System for Windows, Copyright © 2017 SAS Institute Inc. (Cary, NC, USA). A P < 0.05 was classified as statistically significant. Results: Measurements of blood flow of the palatal mucosa showed that the healthy young dentulous participants had significantly lower perfusion unit values than the elderly edentulous participants at all three anatomical sites (P < 0.05). For Group 2, the comparisons between the measurements taken before (E1) and after (E2) new dentures were provided showed no significant differences. Conclusion: Our results indicate that the process of aging significantly modifies the blood flow of the palatal mucosa while wearing removable dental prostheses does not modify the blood flow of the palatal mucosa in a 1week period. These results are not influenced by systemic pathology (e.g., diabetes, cardiovascular diseases) or smoking.

Clinical classification of torus and effectiveness of two-layer bases in removable dentures.

AIM: To study and systematize the complaints of patients with removable prostheses, paying attention to the clinical manifestation of the torus and its sensitivity, and to determine the effectiveness of the use of two-layer bases in removable prosthetics. METHODS: In the clinic of orthopedic dentistry, 104 people were examined and received orthopedic treatment, including 37 patients in the comparison group. The main number of patients up to 55.3, complained of poor fixation and violation of the chewing process. In order to improve the functional efficiency of the removable prosthesis, two-layer bases using soft linings, Gossil (Russia), Furji (Japan), and Mucopren (Germany), are proposed. Clinical and laboratory studies were conducted (Estesmary, gattingeri, physico-mechanical studies of soft linings). The effectiveness of using soft pads in removable prosthetics is shown. The conducted research allowed creating a clinical classification of the torus depending on the pain sensitivity of the oral mucosa-type I-painless torus, type II-moderately painful, and type III-painful when touched. The features of the technology for manufacturing two-layer bases for type II and type III of torus are recommended. RESULTS: It was found that 47.9% of patients in the comparison group and 55.3% of those examined in the main group complained about impaired chewing and poor fixation of dentures on the upper and lower jaws, depending on the condition of oral tissues. The patients did not always objectively assess the condition of their dentures. Patients complained about lack of stabilization, poor-quality dentures, and the need to replace the old denture with a new one in 13.8% of cases in the control group and 31.9% in the main group of patients examined. CONCLUSION: In the case of removable denture wearers with a total lack of teeth, there were 55.3% complaints of chewing disorders and poor fixation of dentures, and in the case of partially removable denture wearers, the greatest number of complaints of clasp fixation disorders were found in 42.1% of cases. Physico-mechanical study of soft linings from different countries, Gossil (Russia), Fuji (Japan), Mukopren (Germany), showed their effectiveness and the possibility of their use orthopedic dentistry.

[Comparison of the effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings].

PURPOSE: To compare the different effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings. METHODS: A total of 80 patients with dentition defects of Ken's Class Ⅰ and Subclass Ⅱ were selected from the Department of Prosthodontics. The patients were randomly divided into 2 groups, with removable dentures made by using 3D printing and plaster casting method, respectively. The patients were asked to re-visit 1 week after wearing the dentures to observe and record intraoral mucosal tenderness points. At the same time, mastication efficiency was measured by absorbance method. The patients were followed up for 2 months after wearing dentures, and questionnaires were issued to them to investigate subjective feelings and satisfaction. The subjective feelings of patients included masticatory ability, retention effect, convenience, comfort, speech function and facial appearance. Satisfaction evaluation included three aspects: treatment duration, cost and final outcome. Each aspect of evaluation used a 5-point system, with a minimum score of 1 and a maximum score of 5. The higher the score, the better the patient's subjective feelings or the higher the satisfaction. The data were statistically analyzed with SPSS 17.0 software package. RESULTS: The tender points in 3D printing group was less than the plaster casting group, while the chewing efficiency of 3D printing group was higher than the plaster casting group, the difference was statistically significant (P＜0.05). The difference of subjective feeling and satisfaction was also significant between the two groups(P＜0.05). CONCLUSIONS: 3D printing to make removable denture has certain advantages in improving the accuracy of removable denture and the comfort of patients.