Influence of Pigment and Opacifier on Dimensional Stability and Detail Reproduction of Maxillofacial Silicone Elastomer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of opacifiers on dimensional stability and detail reproduction of maxillofacial silicone elastomer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The effect of disinfectant solutions on the hardness of acrylic resin denture teeth

This investigation studied the effects of disinfectant solutions on the hardness of acrylic resin denture teeth. The occlusal surfaces of 64 resin denture teeth were ground flat with abrasives up to 400-grit silicon carbide paper. Measurements were made after polishing and after the specimens were stored in water at 37 degreesC for 48 h. The specimens were then divided into four groups and immersed in chemical disinfectants (4% chlorhexidine; 1% sodium hypochlorite and sodium perborate) for 10 min. The disinfection methods were performed twice to simulate clinical conditions and hardness measurements were made. Specimens tested as controls were immersed in water during the same disinfection time. Eight specimens were produced for each group. After desinfection procedures, testing of hardness was also performed after the samples were stored at 37 degreesC for 7, 30, 60, 90 and 120 days. Data were analysed using two-way analysis of variance (anova) and Tukey's test at 95% confidence level. According to the results, no significant differences were found between materials and immersion solutions (P > 0.05). However, a continuous decrease in hardness was noticed after ageing (P < 0.05). It was conclude that the surfaces of both acrylic resin denture teeth softened upon immersion in water regardless the disinfecting solution.

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Incorporation of Disinfectant Solutions on Setting Time, Linear Dimensional Stability, and Detail Reproduction in Dental Stone Casts

Purpose: The aim of this paper was to analyze the influence of incorporation of disinfectants during the cast die stone-setting time. Setting time, linear dimensional stability, and reproduction details on casts were measured.Materials and Methods: Die stone type IV specimens with disinfection solutions (sodium hypochlorite 1%, glutaraldehyde 2%, chlorhexidine 2%) were incorporated in two concentrations (50%, 100%). The detail reproduction, dimensional stability, and setting time were tested in accordance with ADA recommendations.Results: Disinfecting solutions promoted an increase in setting time compared to control; sodium hypochlorite was responsible for the highest setting time. The addition of undiluted sodium hypochlorite 1.0% led to contraction during setting, but the groups with 50% diluted sodium hypochlorite 1.0% and undiluted chlorhexidine 2.0% resulted in intermediate values compared to the other groups, thus matching the control. The others did not demonstrate any effect on expansion. For detail reproduction, it was observed that the control group presented results similar to the others, except those where sodium hypochlorite was added.Conclusions The addition of sodium hypochlorite in both dilutions significantly altered, negatively, all the evaluated properties. But the addition of glutaraldehyde and chlorhexidine did not promote any significant alterations in the evaluated properties.

Effectiveness of two disinfectant solutions and microwave irradiation in disinfecting complete dentures contaminated with methicillin-resistant Staphylococcus aureus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biossegurança e odontologia: crenças e atitudes de graduandos sobre o controle da infecção cruzada

Este estudo teve o objetivo de investigar as percepções de graduandos de Odontologia sobre a fidelidade às diretrizes de biossegurança e acerca do preservar-se. Nove questões abertas, que abordaram aspectos de interesse para o tema, foram aplicadas em entrevista com 14 acadêmicos, que realizavam atendimento odontológico de pacientes da Faculdade de Odontologia de Araraquara da Unesp. Utilizou-se a metodologia de pesquisa qualitativa e a estratégia metodológica para análise das entrevistas foi a Discurso do Sujeito Coletivo (DSC). Três figuras metodológicas foram obtidas, sendo ideias-centrais, expressões-chave e o DSC propriamente dito. A análise dos discursos permitiu avaliar a fala natural da coletividade. Verificou-se a adesão dos entrevistados aos protocolos de biossegurança, embora houvesse a queixa de que, na rotina diária, as precauções fossem negligenciadas por não serem muito práticas. Entre as medidas de proteção individual e coletiva, rotineiramente utilizadas, foram apontados o uso de Equipamento de Proteção Individual (EPI) e as barreiras protetoras, bem como as atividades de desinfecção e esterilização. O risco de contágio foi visto por alguns com pavor e por outros com total indiferença porque acreditavam ser algo do qual é possível de se ter controle por meio da adesão às precauções padrão. Entre as doenças de maior preocupação, a aids e as hepatites B e C foram as mais temidas. Diante do discurso obtido, salienta-se a necessidade de se aperfeiçoar as estratégias educacionais, com intuito de motivar a fiel adesão às normas de biossegurança, essenciais no trato de pacientes odontológicos.

Avaliação em escala laboratorial da utilização do processo eletrolítico no tratamento de águas

Water treatment uses chlorine for disinfection causing formation of trihalomethanes. In this work, an electrolytic water pre-treatment was studied and applied to the water from a fountainhead. The action against microorganisms was evaluated using cast-iron and aluminum electrodes. Assays were made in laboratory using the electrolytic treatment. After 5 min of electrolysis the heterotrophic bacteria count was below 500 cfu/mL and complete elimination of total and fecal coliforms was observed. Using electrolytic treatment as a pretreatment of conventional tap water treatment is proposed.

Avaliação (em escala laboratorial) da aplicação do processo eletrolítico em efluente de lagoa de estabilização de esgoto urbano

Physico-chemical and microbiological parameters were evaluated before and after applying an electrolytic process to effluents of a stabilization lagoon, in the presence or absence of salt. Chlorine generation and bactericidal properties of the treatments were studied following two experiments. Effluent pH increased with electrolysis time. In the absence of salt, 20 min electrolysis resulted in a COD (Chemical Oxygen Demand) reduction of 44%, along with ca. 99.9% (3 log10 cfu/mL) reduction in total coliforms, heterotrophic bacteria and Escherichia coli. These results indicated that the electrolytic process is a promising complementary technology to improve effluent quality for stabilization lagoons.

Effects of the electrolytic treatment on Bacillus subtilis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de desinfetantes de superfície utilizados em Odontologia

Desinfecção de superfície é um procedimento realizado nas áreas externas do equipamento odontológico e demais itens do consultório. O objetivo deste trabalho foi analisar a ação de quatro desinfetantes utilizados em Odontologia: álcool etílico a 77°GL, composto fenólico (Duplofen), iodóforo (PVP-I) e solução de álcool etílico a 77°GL com 5% de clorexidina para desinfecção de superfície. Foram analisados quatro pontos em cada equipamento (carter, pia de lavagem de mãos, encosto de cabeça da cadeira e superfície frontal externa do refletor), utilizando-se a técnica de spray-wipe-spray. de cada ponto, foram coletadas amostras utilizando-se placas de superfície contendo ágar Mitis Salivarius bacitracina sacarose, ágar Sabouraud Dextrose com cloranfenicol, ágar MacConkey e ágar-sangue para contagem de estreptococos do grupo mutans, leveduras do gênero Candida, bactérias gram-negativas e contagem total de microrganismos, respectivamente (ufc/placa). Os resultados foram analisados estatisticamente utilizando-se teste t de Student para comparação entre as médias de ufc/placa. O desinfetante que demonstrou ser mais efetivo na redução microbiana foi a solução alcoólica de clorexidina, principalmente para bactérias gram-positivas. O iodo e o composto fenólico mostraram ser bastante eficazes na redução microbiana. O álcool etílico a 77°GL foi o menos eficaz dos quatro desinfetantes analisados, mas apesar de não ser indicado como desinfetante de superfície, mostrou, no presente trabalho, redução microbiana estatisticamente significativa após o processo de desinfecção.

Effects of Nd : YAG and Er : YAG lasers on the sealing of root canal fillings

Objective: the ability of the laser irradiation to promote the cleaning and disinfection of the radicular canal system has become this type of treatment in a viable and real alternative in endodontics. The purpose of this study was to evaluate the apical marginal sealing of root canal fillings after the irradiation with the laser of Nd:YAG or of Er:YAG. Materials and Methods: Forty-two human, extracted single-rooted teeth had their crowns sectioned and the root canals prepared with a no. 70 K-file. Then, they were dried and divided into three groups according to canal wall treatment: group 1: the canals were filled with EDTA for 3 min, followed by irrigation with 1% sodium hypochlorite solution; group 2: the canal walls were irradiated with Nd:YAG laser; and group 3: the canal walls were irradiated with Er:YAG laser. Afterwards, the root canals were obturated by the lateral condensation technique. The roots were externally waterproof, except in the apical foramen and immerged in 2% methylene blue aqueous solution during 48 hours. Results: the results showed that the largest infiltrations happened in the group 3-Er:YAG (7.3 mm), proceeded by the group 1-EDTA (1.6 mm) and by the group 2-Nd:YAG (0.6 mm). The group Er:YAG differed statistically of the others (p < 0.05). Conclusion: It was concluded that the Er:YAG laser intracanal irradiation previously to the root canal filling must be used with caution until future research is define the best parameters for it's use.

Proposal of Using Ozonated Water to Control Biofilm Formation on Mouth-Related Devices

The purpose of this study was to evaluate the antimicrobial effectiveness and dental applications of ozonated water generated by portable equipment (0.667 mg/L). Total elimination of C. albicans, E. coli and S. mutans planktonic cells was observed after 5 min. Reduction in the number of viable cells of biofilms formed on acrylic resin was observed for C. albicans, S. mutans and E. coli. The same effect was observed on biofilms of E. coli, S. aureus, S. mutans and C. albicans formed on stainless steel. Ozonated water was effective for the disinfection of experimentally contaminated toothbrushes.

Microbiological and physicochemical treatments applied to metallurgic industry aiming water reuse

Estudou-se o reuso de água de um sistema composto por estação de tratamento de esgoto (ETE) com aeração prolongada e lodo ativado, e em uma estação compacta de tratamento de água (ECTA) de uma indústria metalúrgica. Os processos para obtenção da água de reuso foram: microbiológico e físico-químico. O esgoto doméstico foi bombeado para a ETE, onde houve formação de flocos biológicos e água clarificada. Avaliou-se a eficiência do processo microbiológico da ETE mediante a remoção de demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO) e sólidos sedimentáveis (SS). A eficiência do processo físico-químico de clarificação e desinfecção foi avaliada mediante análises de pH, turbidez, cor, contagem de bactérias heterotróficas aeróbias, cloro livre, dureza, alcalinidade, cloretos, sulfatos, sólidos totais dissolvidos (STD). Na água de reuso além desses parâmetros avaliou-se a toxicidade aguda ao microcrustáceo Daphnia similis.

Inactivation and disposal of by-products from Mycobacterium smegmatis by photoelectrocatalytic oxidation using Ti/TiO2-Ag nanotube electrodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)