Newton's Classification Research Articles

Interrelationship between Candida Colonization, Dentures, and Mucosal Tissue Inflammation in the Pathogenesis of Denture Stomatitis.

Despite being common, the pathogenesis of denture stomatitis (DS) is poorly known; thus, this study was conducted to examine the relationship between candida, dentures, and mucosal tissue inflammation. One hundred and twenty edentulous patients wearing a denture with clinical signs and symptoms of DS and 30 patients without DS as healthy were involved in the study. Patients with DS were divided into three groups according to Newton's classification and fungal colonies, and denture fit was assessed. No significant difference was observed between age, sex, and denture fit between the two groups (P > 0.05). The fungal colonies in patients with DS were significantly more than the controls. The majority of the patients with good denture fit had degree 1 (localized mucosal inflammation), while the majority of the patients with fair denture fit had degree 2 (diffuse inflammation on the denture bearing area) and the majority with poor denture fit had degree 3 (granular type) (P < 0.001). The fungal colonies were negative for the majority of degree 1 patients (57.1%), while they were positive for the majority of patients with degree 2 (61.3%) and degree 3 (63.2%) inflammation (P = 0.003). We concluded that the pathogenesis of DS is elusive. Multiple factors, including lack of hygiene, reduced salivary flow, poor denture care, and fit, provide an easy pathway for Candida strains to colonize dentures.

Abstract P377: Effect Of Treatment Of Denture Stomatitis On Blood Pressure, C-reactive Protein, Body Mass Index, And Lipid Profile.

Background: The literature shows that partially or entirely edentulous patients can have an increased risk of cardiovascular diseases, particularly hypertension and stroke. However, edentulous patients wearing complete dentures present Denture Stomatitis (DS) very frequently, associated with deleterious cardiovascular effects, mainly arterial hypertension. Objective: This study evaluated blood pressure, C-reactive protein (CRP), body mass index (BMI), and lipid profiles of completely edentulous DS-positive patients at baseline, and after 15 and 45 days of treatment. Methods: The treatment protocol consists of brushing the palate with a soft brush and water, denture brushing with a denture-specific brush and mild soap, and oral, topical application of nystatin 100,000 IU. The degree of DS was diagnosed by two calibrated and blinded researchers using the modified Newton classification. Three measurements were performed at 5-minute intervals recording the systolic and diastolic blood pressure. The ELISA assessed the CRP (mg/L) of blood samples. The Friedman test and Dunn's post-test evaluated blood pressure (mmHg), BMI (kg/m 2 ), and lipid profile (mg/dL) data. ANOVA and Tukey's post-test was applied for CRP using the software SPSS 25.0 (p&lt;0.05). Results: Twenty-five participants were included, with a mean age of 68±6.4 years.DS degree decreased over time (p&lt;0.001), significantly decreasing after 15 days and intermediate values after 45 days. Systolic blood pressure showed a trend for reduction at 15 days (147.9±17.3 vs. 141.7±19.0 mmHg; p=0.058) and a significant decrease after 45 days (147.9±17.3 vs. 140.5±14.1 mmHg; p=0.017), while diastolic blood pressure was similar over time (88±13.3, 87±10.5 and 86±9.8 mmHg). The treatment did not significantly affect the CRP (1.3±0.9; 1.3±0.1; 1.1±0.1 mg/L; p=0.824), BMI (30.1±6; 30.3±6; 30.2±6 kg/m 2 ; p=0.391), and lipid profile (Total cholesterol: 187.3±39; 185.2±40; 185.3±33 mg/dl; p=0.416, HDL: 48.9±11.5; 49.0±9.8; 47.4±11.0 mg/dL; p=0.217). Conclusion: The applied treatment of DS reduced the patients' DS degree and systolic arterial pressure.

Relation between the risk factors for the severity of denture stomatitis and quality of life of complete edentulous individuals: a cross-sectional study.

To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers. Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%. 184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL. Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

A modified Newton classification for denture stomatitis.

The effectiveness of denture stomatitis (DS) treatment should be evaluated by associating clinical and mycological parameters. Although widely used in clinical studies, the Newton classification does not accurately represent the degree of severity of palatal inflammation in terms of extent of the lesions and intensity of the erythema. Therefore, a modified Newton classification has been proposed considering the coverage area of palatal inflammation and the erythema level. This consistent and direct ranking will help standardise randomised clinical trials, as well as the statistical comparison among blind evaluations of the obtained scores within and between studies.

Analysis of numerical simulation models for the turbo air classifier

AbstractThe comparative analysis on the flow field of turbo air classifier, using different turbulence models and moving region calculation models, is completed based on ANSYS‐FLUENT. The simulation results show both RNG k‐ϵ and Reynolds stress models have the high calculation accuracy with the low computational cost. There are slightly different at the interface between the moving and static regions for multiple reference frame (MRF) model and sliding mesh (SM) model. However, the iteration number of multiple reference frame model is far less than that of sliding mesh model with the same calculation accuracy. Meanwhile, the flow field in the rotor cage channel is well‐distributed when air inlet velocity is close to the linear velocity at outer edge of rotor cage no matter what combination of the models is used among the RNG k‐ϵ model and Reynolds stress model together with multiple reference frame model and sliding mesh model. The classification experiments show the accuracy and the Newton classification efficiency are high when the air inlet velocity is 12 m/s and the rotating speed of rotor cage is 1200 min−1. The experimental results are consistent with simulation results of the flow field in the classifier.

REVIEW OF EARLY CHILDHOOD MAGAZINES IN TERMS OF SCIENTIST IMAGES: THE CASE OF CURIOUS KIDS

&lt;p&gt;This study aimed to examine the curious kids' magazine prepared, published, and sold by TUBITAK, a scientific and technological research institution of Turkey, in terms of the images of scientists it reflects. The data were collected by document analysis method within the scope of qualitative research approach and a total of 80 issues published between 2015-2021 were analyzed. In this process, the data containing text and visuals about scientists were evaluated using Newton and Newton's (1992) classification. It was examined separately by the researchers, taking into account each criterion in the evaluation list, possible differences were also compared. The results revealed that the images of scientists extracted from the magazine have begun to change positively in recent years. Children who follow this magazine can structure predominantly in minds of the scientist as regardless of gender, who dresses comfortably and appropriately for the nature of his work, uses interesting tools and equipment suitable for the nature of his work, although part of it is indoors, it is a person who mostly works outside, works as a team rather than individually, and most importantly, is happy with his work. &lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/edu_01/0977/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Epidemiological factors associated with Candida albicans in patients using complete denture: a scoping review

Objective: This study undertakes a scoping review of research on epidemiological factors of Candida albicans in patients using complete denture (CD). Methods: PubMed, LILACS, Embase, SciELO, Web of Science, and Scopus databases were used. Searches were conducted in December 2020. Keywords used in this search were Candida albicans, Complete Denture, Mouth, and Microbiology. Results: Initially, 89 articles were identified; 19 of these comprised the final sample after applying the exclusion/inclusion criteria. There was a greater tendency for females to use DC. In addition, among all samples evaluating the incidence of the fungus (n = 2,724), approximately 44.7% (n = 1,218) had C. albicans-associated prosthetic stomatitis. Conclusion: Prosthetic stomatitis is a condition that mainly affects women aged 50–70 years and has a multifactorial predisposition. Also, Newton's classification proposed in 1962 is the most used for the clinical diagnosis of oral candidiasis. The CD's hygiene status is a crucial factor for the progression of candidosis, in the same way that the C. albicans fungus plays an important role in the progression of this pathogenesis in the host.

Efficacy of essential oil of cinnamon for the treatment of oral candidiasis: A randomized trial.

It was analyzed the efficacy of mouthwash and spray containing essential oil (EO) of Cinnamomum zeylanicum Blume for the treatment of oral candidiasis. A randomized, controlled, and blinded clinical trial was conducted with 36 individuals (probabilistic sample) with oral candidiasis who were divided into two treatment groups: C. zeylanicum (0.5mg/mL), n=18; nystatin (100,000IU/mL), n=18. The efficacy of the products was evaluated by two parameters: (a) clinical evolution recorded by calibrated examiners (Kappa=0.822) according to Newton's classification and (b) reduction of colony-forming units/mL. Mycological and clinical parameters were analyzed before and at 15 days after treatment. Clinical examination of the mucosa showed that C. zeylanicum (p<0.0339) and nystatin (p<.0139) had efficacy, resulting in a reduction of signs and symptoms (Mann-Whitney test). Mycological analysis showed that C. zeylanicum caused a reduction of 61% and 33% of Candida spp., isolates oral mucosa and dentures, respectively. Candida tropicalis strains were eliminated after C. zeylanicum, in both sites. The participants reported a pleasant taste and few product-related complaints. C. zeylanicum EO and nystatin exhibited clinical efficacy, according to the Newton classification, and reducing in Candida spp. The clinical trial has been registered (Registration number: NBR-33s6×5, ensaiosclinicos.gov.br).

Моделирование петрографических структур. Статья 2

For the purposes of modeling and classification of structures and textures of bimineral rocks, a diagram of a new type is proposed — a barycentric tetrahedron (piii, piij, pijj, pjjj) of probabilities of ternary intergrain contacts. The position of the Hardy-Weinberg equilibrium line is calculated. Correspondences between the classification fields and boundaries in the barycentric tetrahedron and the previously proposed barycentric triangle (pii, pij, pjj) of the probabilities of binary intergrain contacts are established. The prospects for the classification of petrographic structures and textures in a barycentric tetrahedron based on Newton's classification of curves of the 3rd order are discussed.

Oral Mucosa Changes Associated with Wearing Removable Acrylic Dentures.

The main purpose of the study was to highlight the incidence of various changes in the oral mucosa associated with wearing removable acrylic dentures. Materials and method. The study was performed on a total of 45 subjects who presented at the Prosthodontics Clinic and the Oral Rehabilitation Clinic of Craiova Faculty of Dental Medicine during January 2018-May 2020. Results. Of the 45 subjects that were wearing at least one acrylic denture 31,11% presented oral mucosa changes or lesions. The most common mucosal lesion was type 1 according to Newton's classification.

Differential Mucosal Gene Expression Patterns in Candida-Associated, Chronic Oral Denture Stomatitis.

Denture stomatitis is a common condition manifested by inflammation of the oral mucous membrane beneath a denture. The objective of this study was to compare the transcriptome of human palatal mucosa with chronic oral stomatitis-associated Candida albicans infection to that of healthy oral mucosa. Oral palatal biopsies were obtained from 17 healthy and 15 C. albicans-infected stomatitis subjects for whole transcriptome analyses. The presence of C. albicans was confirmed by cytology and cultivable methods. The clinical severity of the stomatitis was evaluated by the Newton Classification (Class II or III). For transcriptome analyses a false discovery rate (FDR) of <0.05 was used, and the effects of age, race, and gender were evaluated by principle component analysis (PCA). Specific differentially expressed genes identified by mRNA array data were confirmed by measurements of salivary protein expression using multiplex analyses. Microarray analysis of mRNA expression indicated that in C. albicans stomatitis there were 3034 genes-in-play that were differentially expressed and met the FDR < 0.05 criteria. Two hundred thirty five (235) genes were up-regulated >2-fold, and 71 genes were down-regulated >2-fold. Five of the 6 most significant gene ontology pathways involve inflammation and activation of the immune response with CD28 and CTLA signaling of T cells. There was strong up-regulation of TLR2, CD14, MYD88, IKKA, and NFKB as the dominant toll-like receptor-signaling pathway. The expression of several extracellularly expressed inflammatory protein genes was up-regulated in candidiasis, and 2 were confirmed as up-regulated within the saliva using protein multiplexing analyses. Neutrophil recruitment and activation, epithelial suppression, and T-cell activation appear as major pathways in chronic oral candidiasis. Tissue up-regulation of TLR2 pathways, as well as potential C. albicans binding proteins, was observed, whereas keratin and adhesion molecule synthesis were down-regulated. Several candidate biomarkers to potentially identify the presence of oral candidiasis were differentially expressed in tissues and saliva.

The severity of denture stomatitis as related to risk factors and different Candida spp.

1) To select patients with Candida-related denture stomatitis (DS) and to study possible risk factors associated with DS, 2) to evaluate the severity of DS according to Newton's classification, and 3) to investigate the association between the presence of non-albicans Candida spp. (NAC) or mixed Candida spp. and the severity of DS. Eighty-two patients with Candida-positive DS have undergone 1) filling in the interview questionnaire, 2) clinical examination, and 3) microbiologic examination. A total of 113 Candida spp. isolates were obtained from Candida-positive DS patients: C. albicans (as a single species) in 47/82 (57%) patients (study group A [SG_A]) and NAC/mixed Candida spp. in 35/82 (43%) patients (SG_B). Univariate logistic regression analysis showed that older age, longer age of the mandibular denture, and ex-smoker status were associated with SG_A. A multivariate model revealed no significant predictor of DS severity. Patients from SG_A were 3 times as likely to have DS type I, while patients from SG_B were 4.9 times as likely to have DS type III. Our results show the association between type III of DS (by Newton's classification) and the presence of NAC or mixed Candida spp. in denture wearers.

Laboratory-Based Investigation of Denture Sonication Method in Patients with Candida-Associated Denture Stomatitis.

Denture stomatitis (DS) is a disease characterized by inflammation and erythema of the oral mucosa areas covered by the denture. Multifactorial etiological factors contribute to DS, but it seems that Candida plays the key role. The aim of the study was to evaluate the denture sonication method to: (i) increase the possibility of diagnosing patients with Candida-associated DS; (ii) detect and identify the mixed Candida spp., and (iii) determine the Candida colony forming units (CFU) and its possible relationship with DS severity, based on Newton's classification. The cross-sectional study conducted at the Clinic for Dental Prosthetics, Belgrade (Serbia) from June 2013 to December 2014 enrolled edentulous patients with dentures (n = 250). Patients without DS (n = 20) were the control group (CG). The patients' data were collected, and patients with DS (study group/SG) were selected and divided into SG Candida+ and SG Candida-. Based on severity of DS, the SG patients were classified in 3 groups (Newton's classification). Four sampling methods were applied to detect patients with Candida-associated DS: mucosa swab, denture swab, oral rinse, and denture sonication method. The sensitivity and specificity of denture sonication method were shown using the receiver operating characteristic (ROC) curve and the area under the curve (AUC). In 97 (38.8%), out of 250 clinically examined patients, DS was diagnosed. In 82 (84.5%), out of 97 mycologically examined patients, Candida-associated DS was detected when denture sonication method was applied. Additionally, using the denture sonication method we observed: (i) the largest number of Candida positive patients compared to other sampling methods (p < 0.0001); (ii) the highest number of Candida CFU/ml (105 ), and (iii) the possibility to detect mixed Candida cultures. The largest number of patients with Candida-associated DS showed type II (60%) DS, followed by type I (21%), and type III (19%) DS. The denture sonication method is easy, accurate, and sensitive, and increases the possibility of diagnosing patients with Candida-associated DS. Additionally, yeast quantification, mixed Candida spp., and non-albicans Candida were detectable when cultivation on Candida CHROMagar was performed. It was not possible using conventional methods, such as swab or oral rinse.

Original article. The use of essential oils based antiseptic solution in the treatment of denture stomatitis

Summary Introduction Local therapy of denture stomatitis (DS) associated with Candida species fungi infection usually involves the application of nystatin and miconazole. Due to the fact that these drugs may be less efficient against biofilm and possible resistance development, a new approach in the treatment includes the use of antiseptic agents. The aim of the study was to compare clinical and microbiological therapeutic outcomes of antiseptic solution Listerine® and Daktanol® antifungal oral gel in the treatment of DS associated with Candida species fungi. Material and Methods The study included 30 patients affected by DS, divided into the two treatment groups, control group (n=15) treated by Daktanol® gel and experimental group (n=15) treated by the antiseptic solution Listerine®. Successful treatment was evaluated based on palatal mucosa inflammation reduction classified according to the Newton classification and the difference in the number of fungal colony- forming units (CFU) isolated by smears before and after the treatment that lasted 14 days. Results Reduction in inflammation intensity and fungal CFU number on palatal mucosa (p&lt;0,01) as well as on denture base (p&lt;0,01) were observed in both groups of subjects after the treatment. Conclusion Antiseptic solution Listerine® and Daktanol® antifungal gel both reduced palatal mucosal inflammation and CFU number of fungi in mouth without significant differences among them. CFU number of fungi isolated from denture base was significantly lower after the treatment with Listerine® (p&lt;0.05).

Frecuencia de estomatitis subprotésica en pacientes portadores de prótesis dentales removibles

Introducción: La dentadura parcial removible (DPR), restituye las funciones de masticación, deglución, fonación y respiración. Cuando está mal diseñada o adaptada causa daños en la mucosa oral (MO) de soporte. Entre las lesiones más frecuentes se encuentra la estomatitis subprotésica (ES). La ES se considerada como factor de riesgo para la aparición de lesiones premalignas y malignas en la cavidad oral. Objetivo: Determinar frecuencia de ES en pacientes portadores de DPR que asistan a la consulta odontológica del Hospital Regional de Coronel Oviedo-Paraguay en el año 2015 entre los meses de julio a septiembre. Método: Esta investigación es un estudio observacional descriptivo corte transversal. Resultados: 50 pacientes fueron evaluados. 78% tenía ES. La distribución de la ES fue la siguiente: según la clasificación de Newton: Tipo I = 10%, Tipo II = 60%, Tipo III = 8%; según la clasificación de Kennedy: clase I = 10,26%, clase II = 12,82%, clase III = 56,41%, clase IV = 7,69%, edéntulos totales = 12,82%. La distribución por género y edad fue la siguiente: Masculino = 15,38%, femenino 84,62%; entre 10 y 20 años = 5,13%, entre 21 a 30 años = 30,77%, entre 31 a 40 años = 17,95%, entre 41 a 50 años = 20,51%, entre 51 a 60 años = 20,51%, entre 61 a 70 años = 5,13%. Conclusión: Se encontró una alta prevalencia de ES en portadores de DPR, es sumamente importante tener un programa de control en el cual se pueda monitorear de manera mediata la función y eficacia de la DPR en el tiempo.

Effect of sodium hypochlorite and Ricinus communis solutions on control of denture biofilm: A randomized crossover clinical trial

Statement of problemThe prevalence of complete edentulism remains high in the elderly, and previous data have shown that poor denture hygiene is common among patients with edentulism. PurposeThe purpose of this randomized crossover trial was to evaluate the efficacy of denture cleansers in terms of biofilm removal, antimicrobial action, and the remission of denture stomatitis. Material and methodsFifty denture wearers with denture stomatitis were instructed to brush their dentures (brush and soap) and to soak them (20 minutes/14 days) in 4 solutions, as follows: C (control), 0.85% saline; SH1, 0.1% sodium hypochlorite; SH2, 0.2% sodium hypochlorite; and RC, 8% Ricinus communis. The biofilm in the intaglio surface of maxillary dentures was stained, photographed, and quantified by software (Image Tool). It was then collected (brushed with saline solution), and the obtained suspension was diluted (100 to 10-3) and seeded (50 μL) in CHROMagar for Candida spp. After incubation, colony-forming units per milliliter values were calculated. Denture stomatitis remission was classified according to the Newton classification. Data were analyzed by Friedman (α=.05) and Wilcoxon tests and corrected by the Bonferroni test (α=.005). ResultsSH1 (mean rank [MR]=1.98) and SH2 (MR=1.64) showed lower biofilm coverage than C (MR=3.73) that was similar to RC (MR=2.92). SH1 (MR=2.43) and SH2 (MR=2.10) showed antimicrobial action for Candida spp, and RC (MR=3.36) showed similar results to C (MR=3.51) and baseline (MR=3.50). Clinical signs of denture stomatitis were reduced by SH1 (MR=2.44), while SH2 (MR=2.56) and RC (MR=2.74) showed intermediate results. ConclusionsThe two sodium hypochlorite solutions were the most effective means of biofilm control. All tested solutions were effective in reducing the signs of denture stomatitis.

Analysis and optimization of process parameters affecting classification performances indices of the turbo air classifier

Classification performance indices of a turbo air classifier mainly include cut size, classification precision, and Newton's classification efficiency, which would be effected by the process parameters including air inlet velocity, rotor cage's rotary speed and feeding speed. Orthogonal experiment method was used to analyze the influence of process parameters on the classification performance indices according to quartz sand powder classification experimental data as well as the calcium carbonate classification experimental data. Through range analysis of the orthogonal experiments for quartz sand and calcium carbonate, it is found that air inlet velocity and rotor cage's rotary speed play an important role on classification performance indices including classification accuracy, cut size and its corresponding Newton's classification efficiency. Feeding speed has slight impact on these performance indices. The best optimized combination of the process parameters for quartz sand was: when air inlet velocity was 20 m · s–1, rotor cage rotary speed was 900 min–1 and feeding speed was 56.69 kg · h–1, the high Newton's classification efficiency and classification accuracy could be obtained and the corresponding values were 73% and 0.66. This best optimized combination was among the 9 group orthogonal experiments for quartz sand. The best optimized combination of the process parameters for calcium carbonate was: air inlet velocity was 14 m · s–1, rotor cage rotary speed was 1200 min–1 and feeding speed was 120 kg · h–1. However this best optimized combination wasn't among the 9 group orthogonal experiments for calcium carbonate. The evaluated value of the Newton's classification efficiency of cut size can be obtained, which was 73%. In order to verify this evaluated value, the classification experiment for calcium carbonate with this best optimized combination of process parameters was carried out and experimental value of Newton's classification efficiency was 75%, which was close to the evaluated value. Through orthogonal experiment analysis, the influence law of process parameters on classification performances indices of the turbo air classifier can be acquired and the optimized combination of process parameters can be obtained. It paves the way of the development of the turbo air classifier.

Relationship among local and functional factors in the development of denture stomatitis in denture wearers in northern Brazil

OBJECTIVE: The aim of this study was to evaluate the relationship among functional and qualitative factors in the development of denture stomatitis (DS) (according to Newton's classification) in acrylic-based denture wearers residents from northern Brazil.MATERIAL AND METHOD: A total of 99 patients who wore partial or total acrylic resin-based upper dentures were included in this study. The subjects completed an epidemiological data form that includes the patient's gender, age, local factors (hygiene habits, remove denture to sleep, use of mouthwash, present condition of the denture, age of the denture) and functional factors (vertical dimension at rest, vertical dimension of occlusion, occlusion, retention, and static and dynamic stability). To detect yeasts, samples were collected from the inner surface of the dentures and from the palatal mucosa in contact with it. Subsequently, the samples were cultured on Sabouraud dextrose agar, observing macro and microscopic characteristics.RESULT: In the present study, we did not find any significant relationship between the gender and disease onset. Based on the Newton classification, 36.3% of the patients presented with DS and 89.0% were colonized by yeasts; of these subjects, 50% had type I lesions, 33.3% had type II lesions, and 16.6% had type III lesions. All of the qualitative and local factors, except the use of mouthwash, were clinically relevant to the development of disease.CONCLUSION: Denture stomatitis in denture users in northern Brazil was multifactorial, involving local, functional and microbiological factors.

Correspondence analysis and establishment of evaluation model of classification performance indices for a turbo air classifier

The operational parameters of a turbo air classifier including feeding speed, rotor cage's rotary speed and air inlet velocity affect its classification performance directly, such as cut size, classification precision, classification efficiency, fine powder yield, particle fineness and degree of dispersion. Current methods of optimizing operational parameters and improving the classification performance of a turbo air classifier are almost single objective decision only for one of the classification performance indices. In this paper, the multi-objective programming (MOP) model on classification performance for a turbo air classifier is established to evaluate these performance indices comprehensively and achieve optimal classification performance. To minimize the effect of repeatability within these classification performance indices, correspondence analysis is applied to determine the evaluation indices of this MOP model. According to correspondence analysis on the fine talc classification experimental data as well as the calcium carbonate classification experimental data, there is a very strong correlation between cut size and D90; there is also a very strong correlation between cut size and fine powder yield. Thus D90 and fine powder yield are filtered out and they aren't discussed in the evaluation model. The variation coefficient method is introduced to calculate weights of the evaluation function, and the dimensionless transformation method is used to eliminate the effects of different dimension. Thus, the optimal solution among the experimental data is obtained through solving the evaluation function. For the talc classification experiments, the optimal operational parameter combinations are: the feeding speed is 40 kg · h–1, the air inlet velocity is 5 m · s–1 and the rotor cage's rotary speed is 1200 ⋅ min–1. The classification performance indices are: cut size is 16.5 μm, classification precision index is 0.59, Newton classification efficiency is 57% and degree of dispersion is 2.13. For the calcium carbonate classification experiments, the optimal operational parameter combinations are: the feeding speed is 92 kg · h–1, the air inlet velocity is 12 m · s–1 and the rotor cage's rotary speed is 1200 ⋅ min–1. The classification performance indices are: cut size is 31.4 μm, classification precision index is 0.74, Newton classification efficiency is 74% and degree of dispersion is 1.27. This evaluation model avoids the limitation of evaluation for the single classification performance index and incomplete information got by the means of single factor experiment of operational parameters. It also provides the quantitative evaluating criteria for classification performance of a turbo air classifier, which offers a theoretical basis for effective production. This multi-objective programming optimizing method and evaluation model on classification performance can be applied to other dynamic air classifiers as well.

Optimization of Grinding System for Woody Powder Production

To investigate biomass classification technology, such as rotary classifier, and to select appropriate biomass classifier. Through the change of different feeding rates and rotation speeds of the classifier, the classification efficiency and Newton classification efficiency, specific particle size and uniformity index, the recoveries of coarse and fine powder and energy consumption were measured. The results indicate that feeding rate and rotation speed have an important effect on the classification. When the rotation rate of classifier is 300rpm, the classification efficiency decrease basically, but in 78.96kg/h, it is the maximum. And Newton classification efficiency would decrease at first and then increase, in 88.96kg/h, it is the lowest. When the feed rate are 78.96kg/h and 88.96kg/h, as the rotation speed increases from 50r/min to 150r/min, there is a moderate increase in uniformity coefficient, that means the biomass size distribution becomes narrower. The energy consumption means the pulverizer capacity is larger, the less is the wasted energy. It is a common sense that the larger the mill, the higher the efficiency.