Effect of incorporation of 2-tert-butylaminoethyl methacrylate on flexural strength of a denture base acrylic resin

Polymethyl methacrylate (PMMA) resins have commonly been used as a denture base material. However, denture bases may act as a reservoir for microorganisms and contribute to oral diseases in denture wearers. It is hypothesized that the 2-tert-butylaminoethyl methacrylate (TBAEMA) incorporated to acrylic resins should have antimicrobial activity related to the presence of amino groups on acrylic resin surface. OBJECTIVES: The objectives of this study were to evaluate the presence of amino groups on acrylic resin surface and the influence on flexural strength after incorporation of TBAEMA. MATERIAL AND METHODS: Six groups were divided according to the concentration of TBAEMA incorporated to acrylic resin (Lucitone 550): 0, 0.5, 1.0, 1.5, 1.75 and 2%. Specimens surface were evaluated by Electron Spectroscopy for Chemical Analysis (ESCA) to detect the presence of amino groups, represented by nitrogen ratios. Flexural strength of the specimens was tested and results were analyzed by ANOVA and Tukey's test (α=0.05). RESULTS: Different nitrogen ratios were observed on specimen surfaces: 0, 0.13, 0.74, 0.66, 0.92 and 0.33% for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively. Significant differences were found for flexural strength (

Effect of an acrylic resin combined with an antimicrobial polymer on biofilm formation

OBJECTIVES: The purpose of this study was to evaluate the antimicrobial activity of an acrylic resin combined with an antimicrobial polymer poly (2-tert-butylaminoethyl) methacrylate (PTBAEMA) to inhibit Staphylococcus aureus, Streptococcus mutans and Candida albicans biofilm formation. MATERIAL AND METHODS: Discs of a heat-polymerized acrylic resin were produced and divided according to PTBAEMA concentration: 0 (control), 10 and 25%. The specimens were inoculated (10(7) CFU/mL) and incubated at 37ºC for 48 h. After incubation, the wells were washed and each specimen was sonicated for 20 min. Replicate aliquots of resultant suspensions were plated at dilutions at 37ºC for 48 h. The number of colony-forming units (CFU) was counted and expressed as log (CFU+1)/mL and analyzed statistically with α=.05. RESULTS: The results showed that 25% PTBAEMA completely inhibited S. aureus and S. mutans biofilm formation. A significant reduction of log (CFU+1)/mL in count of S. aureus (control: 7.9±0.8A; 10%: 3.8±3.3B) and S. mutans (control: 7.5±0.7A; 10%: 5.1±2.7B) was observed for the group containing 10% PTBAEMA (Mann-Whitney,

One-year prospective clinical study comparing patient satisfaction and masticatory performance of mandibular overdentures supported by one versus two implants

There is a lack of clinical evidence on mandibular overdentures (MOD) supported by a single implant. Objective: To compare patient satisfaction and masticatory performance in MOD supported by one versus two implants in a two-group parallel randomized clinical trial. Material and Methods:Twenty-one patients wearing new maxillary and mandibular complete dentures (CDs) were randomly divided to receive one (GI, n = 11) or two (GII, n = 10) implants in the mandibular arch. Four months after implant placement, o-ring abutments were installed in the implants, and matrix attachments were placed in the lower complete dentures. Patient satisfaction with their dentures and masticatory performance were compared at baseline, 3, 6, and 12 months after the procedure. Data on patient satisfaction were analyzed using the Friedman test and the Mann-Whitney U test. Data on masticatory performance were analyzed using one-way repeated measures analysis of variance (ANOVA) and Student's t test (α=0.05). Results: Both groups exhibited a significant increase in overall patient satisfaction in all periods evaluated (p<0.05), except for GI after 12 months, which had values similar to baseline (p=0.74). Satisfaction levels of GI and GII were similar at baseline, 3 and 6 months, but GII showed higher satisfaction levels (p=0.01) than GI at 12 months. GI and GII exhibited a significant increase (p<0.05) in masticatory performance for all periods relative to baseline. However, GII had higher masticatory performance with dentures than GI, regardless of the period (p<0.05). Conclusion: MOD supported by two implants demonstrated better patient satisfaction in the follow-up at 12 months and better masticatory performance than MOD supported by one implant. &nbsp

Early mobilisation in critically ill COVID-19 patients: a subanalysis of the ESICM-initiated UNITE-COVID observational study

Background Early mobilisation (EM) is an intervention that may improve the outcome of critically ill patients. There is limited data on EM in COVID-19 patients and its use during the first pandemic wave. Methods This is a pre-planned subanalysis of the ESICM UNITE-COVID, an international multicenter observational study involving critically ill COVID-19 patients in the ICU between February 15th and May 15th, 2020. We analysed variables associated with the initiation of EM (within 72 h of ICU admission) and explored the impact of EM on mortality, ICU and hospital length of stay, as well as discharge location. Statistical analyses were done using (generalised) linear mixed-effect models and ANOVAs. Results Mobilisation data from 4190 patients from 280 ICUs in 45 countries were analysed. 1114 (26.6%) of these patients received mobilisation within 72 h after ICU admission; 3076 (73.4%) did not. In our analysis of factors associated with EM, mechanical ventilation at admission (OR 0.29; 95% CI 0.25, 0.35; p = 0.001), higher age (OR 0.99; 95% CI 0.98, 1.00; p ≤ 0.001), pre-existing asthma (OR 0.84; 95% CI 0.73, 0.98; p = 0.028), and pre-existing kidney disease (OR 0.84; 95% CI 0.71, 0.99; p = 0.036) were negatively associated with the initiation of EM. EM was associated with a higher chance of being discharged home (OR 1.31; 95% CI 1.08, 1.58; p = 0.007) but was not associated with length of stay in ICU (adj. difference 0.91 days; 95% CI − 0.47, 1.37, p = 0.34) and hospital (adj. difference 1.4 days; 95% CI − 0.62, 2.35, p = 0.24) or mortality (OR 0.88; 95% CI 0.7, 1.09, p = 0.24) when adjusted for covariates. Conclusions Our findings demonstrate that a quarter of COVID-19 patients received EM. There was no association found between EM in COVID-19 patients' ICU and hospital length of stay or mortality. However, EM in COVID-19 patients was associated with increased odds of being discharged home rather than to a care facility. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021)

Efeito da guia de desoclusão pelo canino, em compraração á oclusão balanceada bilateral, sobre a satisfação e parâmetros cinesiográficos em usuários de próteses totais

Objetivos: O objetivo deste estudo foi comparar os efeitos da desoclusão pelo canino, em comparação à oclusão balanceada bilateral, sobre a satisfação e parâmetros cinesiográficos de usuários de próteses totais, por meio de um estudo “cross-over”. Material e Métodos: Cinquenta pacientes desdentados receberam novas próteses totais bimaxilares. Após ajustes intra-orais e um período de adaptação, 44 participantes foram incluídos no estudo e receberam aleatoriamente uma sequência de esquemas oclusais: oclusão balanceada bilateral seguida de desoclusão pelo canino, ou desoclusão pelo canino seguida de oclusão balanceada bilateral. As avaliações foram realizadas após 30 dias de cada esquema oclusal. Os participantes responderam a um questionário de satisfação com as próteses e um cinesiógrafo registrou os movimentos mandibulares fisiológicos e o movimento da prótese total maxilar durante a mastigação. O teste de Wilcoxon e o teste t de Student foram utilizados para comparar os níveis de satisfação e os dados cinesiográficos para cada esquema oclusal, respectivamente (α = 0,05). Resultados: Os resultados não mostraram diferenças entre os esquemas oclusais em relação à satisfação dos participantes e em nenhum dos parâmetros cinesiográficos avaliados, exceto para a intrusão vertical da prótese maxilar durante a mastigação, que foi 0,1mm menor com a desoclusão pelo canino. Conclusão: Pode-se concluir que: 1) A satisfação de pacientes desdentados com as próteses totais não é influenciada pelo esquema oclusal; 2) Os movimentos mandibulares de abertura e fechamento, o espaço funcional livre e os movimentos da mandíbula durante a mastigação não são alterados em função da utilização da oclusão balanceada bilateral ou desoclusão pelo canino; 3) A desoclusão pelo canino promove menor intrusão da prótese total superior, embora...Objectives: The objective of this study was to compare the effects of canine guidance and bilateral balanced occlusion on satisfaction and kinesiographic parameters of complete denture wearers, by means of a cross-over trial. Material and Methods: Fifty edentulous patients received new maxillary and mandibular complete dentures. After the intraoral adjustments and adaptation period, 44 participants were enrolled in the trial and randomly received a sequence of occlusal schemes: bilateral balanced occlusion followed by canine guidance, or canine guidance followed by bilateral balanced occlusion. The evaluations were performed after 30 days of each occlusal scheme. Participants answered a denture satisfaction questionnaire and a kinesiograph instrument recorded mandibular physiologic movements and pattern of maxillary denture movement during chewing. Wilcoxon test and paired sample t-test were used to compare satisfaction levels and kinesiographic data for each occlusal scheme, respectively (α= .05). Results: The results showed no differences between occlusal schemes on participant’s satisfaction and in any of the kinesiographic parameters studied, except for the vertical intrusion of the maxillary complete denture during chewing, which was .1mm lower with canine guidance. Conclusion: It can be concluded that: 1) The satisfaction of edentulous patients with theirs dentures is not influenced by occlusal scheme; 2) The mandibular movements of opening and closing, the freeway space and the jaw movement during chewing are not altered by the use of the bilateral balanced occlusion or canine guidance in their dentures, 3) The canine guidance promotes less intrusion of the maxillary complete dentures, although the values found are not clinically relevant; 4) The canine guidance or bilateral balanced occlusion are appropriate occlusal scheme and recommended for making... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Incorporação de um metacrilato com ação antimicrobiana em uma resina acrílica para base protética: caracterizaçãp Química e efeito sobre resistência flexural e temperatura de transição vítrea

Muitas tentativas de incorporar agentes antimicrobianos a resinas acrilicas para base protetica tem sido realizadas visando prevenir inflamacoes nos tecidos orais de usuarios de proteses. Entretanto, essas substancias podem ser liberadas da resina acrilica e afetar suas propriedades mecanicas. O metacrilato 2-ter-butilaminoetilo (TBAEMA) e uma substancia policationica que pode apresentar atividade antimicrobiana a partir de grupos amina presentes em sua composicao. Objetivos: 1) investigar uma possivel uniao quimica entre o TBAEMA e a matriz de uma resina acrilica e avaliar a presenca de grupos amina na superficie dos especimes; 2) verificar os efeitos causados pela incorporacao de TBAEMA sobre a resistencia flexural e a temperatura de transicao vitrea (Tg) da resina acrilica. Material e Método: Foram confeccionados especimes a partir de uma resina acrilica termopolimerizavel (Lucitone 550) contendo diferentes concentracoes de TBAEMA (0%, 0,5%, 1%, 1,50%, 1,75% e 2%) e posteriormente foram submetidos a avaliacoes em Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Espalhamento Superficial de Eletrons com Analise Quimica (ESCA) e Calorimetria Diferencial de Varredura (DSC). A avaliacao de resistencia a flexao foi realizada de acordo com as normas ISO/FDIS 1567. Resultados: Atraves de FTIR, observou-se bandas de absorcao na regiao 1300-1320 cm-1 do espectro dos grupos de resina acrilica modificada. Diferentes indices de Nitrogenio foram observados na superficie dos especimes atraves de analises em ESCA. A Tg diminuiu de acordo com a incorporacao de TBAEMA. A resistencia a flexao foi avaliada por meio de analise de variancia a um fator (ANOVA) seguida pelo teste de Tukey (α= 0,05). Observou-se que a resistencia a flexao diminuiu significativamente apos a adicao de TBAEMA em concentracoes de 1%, 1,5%, 1,75% e 2% (p<0,05). Conclusão: Pode ser concluido que: 1) Houve evidencias...Several attempts to incorporate antimicrobials agents into denture base resins have been reported in order to prevent inflammation of oral tissues in denture wearers. However, these substances may be released from acrylic resins and affect their mechanical properties. The 2-tertbutylaminoethyl methacrylate (TBAEMA) is a polycationic substance that may displays antimicrobial activity from pendant amino groups. Objectives: 1) to investigate the possible chemical bound of TBAEMA to the matrix of acrylic resin and to analyze the presence of amino groups on the specimen surface; 2) to evaluate the effect of the incorporation of TBAEMA on flexural strength and glass transition temperature (Tg) of an acrylic resin. Material and Methods: Specimens were prepared from a heat-polymerized acrylic resin (Lucitone 550) mixed to different concentrations of TBAEMA (0%, 0.5%, 1%, 1.50%, 1.75% and 2%) and were submitted to Fourier Transform Infrared (FTIR) Spectroscopy, Electron Spectroscopy for Chemical Analysis (ESCA) and Differential Scanning Calorimetry (DSC) analyses. Flexural strength tests were performed according to ISO/FDIS 1567 specifications. Results: FTIR analysis showed absorbance bands at 1300-1320 cm-1 in the spectrum of TBAEMA-modified acrylic resin groups. Different nitrogen ratios were observed on specimens surfaces by ESCA measurements. The Tg decreased with incorporation of TBAEMA. Flexural strength data were analyzed by one-way ANOVA followed by Tukey’s test (α= .05). The flexural strength decreased with the addition of 1%, 1.5%, 1.75% e 2% of TBAEMA (p<0.05). Conclusion: Within the limitations of this study, it may be concluded that: 1) There was an evidence of copolymerization between acrylic resin and TBAEMA and the presence of nitrogen indicate that amine groups were found on the specimens surfaces; 2) Flexural strength and glass transition temperature were affected after... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Surface properties and color stability of an acrylic resin combined with an antimicrobial polymer

INTRODUCTION: The occurrence of stomatitis is common since the surface characteristics of the dentures may act as reservoirs for microorganisms and have the potential to support biofilm formation. PURPOSE: To assess the surface properties (wettability/roughness) and color stability of an acrylic resin combined with the antimicrobial polymer poly (2-tert-butylaminoethyl) methacrylate (PTBAEMA). MATERIAL AND METHOD: Thirty disc-shaped specimens of an acrylic resin (Lucitone 550) were divided into three groups: 0% (control); 5% and 10% PTBAEMA. Surface roughness values (Ra) were measured using a profilometer and wettability was determined through contact angle measurements using a goniometer and deionized water as a test liquid. Color data were measured with a spectrophotometer. Kruskal-Wallis and Dunn's test were used to compare roughness values. Wettability data were analyzed using ANOVA and Tukey's test. Color data were compared using the Student's t-test and ∆E values were classified according to the National Bureau of Standards (NBS). All statistical analyses were performed considering α=.05. RESULT: Significant differences (p<.05) were detected among the groups for roughness, wettability and color stability. According to the NBS, the color changes obtained in the 5% and 10% PTBAEMA groups were appreciable and much appreciable, respectively. CONCLUSION: It could be concluded that PTBAEMA incorporation in an acrylic resin increased the roughness and wettability of surfaces and produced color changes with clinical relevance.INTRODUÇÃO: A ocorrência de estomatite protética é relativamente comum uma vez que as superfícies das próteses bucais representam um ambiente propício para adesão de microrganismos orais e formação de biofilme. OBJETIVO: Avaliar as propriedades de superfície (molhabilidade/rugosidade) e estabilidade de cor de uma resina acrílica combinada com o polímero antimicrobiano poli (2-tert-butilaminoetil) metacrilato (PTBAEMA). MATERIAL E MÉTODO: Trinta espécimes em formato de disco de uma resina acrílica (Lucitone 550) foram divididos em três grupos: 0% (controle), 5% e 10% PTBAEMA. Os valores de rugosidade (Ra) foram medidos utilizando um rugosímetro, e a molhabilidade foi determinada através de medições de ângulo de contato utilizando um goniômetro e água deionizada como líquido teste. Dados de cores foram medidos com um espectrofotômetro. Os testes de Kruskal-Wallis e Dunn foram utilizados para comparar os valores de rugosidade. Os dados de molhabilidade foram analisados utilizando-se ANOVA e teste de Tukey. Os dados de cor foram comparados com o teste t de Student e valores ΔE foram classificados de acordo com o National Bureau of Standards (NBS). Todas as análises estatísticas foram realizadas considerando α = 0,05. RESULTADO: Diferenças significativas (p<0,05) foram detectadas entre os grupos para rugosidade, molhabilidade, e estabilidade de cor. De acordo com o NBS, as alterações de cor obtidas nos grupos 5% e 10% PTBAEMA foram marcante e extremamente marcante, respectivamente. CONCLUSÃO: Pode-se concluir que a incorporação de PTBAEMA em uma resina acrílica aumentou a rugosidade e molhabilidade das superfícies e produziu alterações de cor com relevância clínica.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Surface properties and color stability of an acrylic resin combined with an antimicrobial polymer

INTRODUCTION: The occurrence of stomatitis is common since the surface characteristics of the dentures may act as reservoirs for microorganisms and have the potential to support biofilm formation. PURPOSE: To assess the surface properties (wettability/roughness) and color stability of an acrylic resin combined with the antimicrobial polymer poly (2-tert-butylaminoethyl) methacrylate (PTBAEMA). MATERIAL AND METHOD: Thirty disc-shaped specimens of an acrylic resin (Lucitone 550) were divided into three groups: 0% (control); 5% and 10% PTBAEMA. Surface roughness values (Ra) were measured using a profilometer and wettability was determined through contact angle measurements using a goniometer and deionized water as a test liquid. Color data were measured with a spectrophotometer. Kruskal-Wallis and Dunn's test were used to compare roughness values. Wettability data were analyzed using ANOVA and Tukey's test. Color data were compared using the Student's t-test and ∆E values were classified according to the National Bureau of Standards (NBS). All statistical analyses were performed considering α=.05. RESULT: Significant differences (p<.05) were detected among the groups for roughness, wettability and color stability. According to the NBS, the color changes obtained in the 5% and 10% PTBAEMA groups were "appreciable" and "much appreciable", respectively. CONCLUSION: It could be concluded that PTBAEMA incorporation in an acrylic resin increased the roughness and wettability of surfaces and produced color changes with clinical relevance