Hepatitis E virus infection increases the risk of diabetes and severity of liver disease in patients with chronic hepatitis C virus infection.

OBJECTIVES: Co-infection with hepatitis A or B viruses may aggravate liver injury in patients infected with hepatitis C virus (HCV). However, few studies have assessed co-infection with hepatitis E virus (HEV) and HCV. Therefore, this study aimed to assess the prevalence and impact of HEV infection among Brazilian patients with chronic HCV infection. METHODS: This observational study included adult patients with chronic HCV infection who were naive to antiviral therapy from January 2013 to March 2016. A total of 181 patients were enrolled, and HEV serology and PCR were performed for all patients. RESULTS: Seropositivity for anti-HEV IgG was detected in 22 (12.0%) patients and anti-HEV immunoglobulin M in 3 (1.6%). HEV RNA showed inconclusive results in nine (4.9%) patients and was undetectable in the remaining patients. HEV serology positive patients had more severe liver disease, characterized by liver fibrosis ≥3 versus ≤2 (p<0.001), Aspartate Aminotransferase-to-Platelet Ratio Index of ≥1.45 (p=0.003), and Fibrosis-4 score of ≥3.25 (p=0.001). Additionally, the odds of HEV-positive patients developing diabetes mellitus were 3.65 (95% CI 1.40-9.52) times the corresponding odds of HEV-negative patients. A case-control-based histological analysis (n=11 HEV-HCV-positive patients and n=22 HCV-positive patients) showed no significant differences between the groups. CONCLUSIONS: This prevalence is higher than that reported in previous studies of the general population in Brazil. Thus, HEV infection may influence the severity of liver disease and may represent an additional risk of developing diabetes mellitus in patients with HCV infection.

Hepatitis E virus infection increases the risk of diabetes and severity of liver disease in patients with chronic hepatitis C virus infection

OBJECTIVES: Co-infection with hepatitis A or B viruses may aggravate liver injury in patients infected with hepatitis C virus (HCV). However, few studies have assessed co-infection with hepatitis E virus (HEV) and HCV. Therefore, this study aimed to assess the prevalence and impact of HEV infection among Brazilian patients with chronic HCV infection. METHODS: This observational study included adult patients with chronic HCV infection who were naive to antiviral therapy from January 2013 to March 2016. A total of 181 patients were enrolled, and HEV serology and PCR were performed for all patients. RESULTS: Seropositivity for anti-HEV IgG was detected in 22 (12.0%) patients and anti-HEV immunoglobulin M in 3 (1.6%). HEV RNA showed inconclusive results in nine (4.9%) patients and was undetectable in the remaining patients. HEV serology positive patients had more severe liver disease, characterized by liver fibrosis ≥3 versus ≤2 (p<0.001), Aspartate Aminotransferase-to-Platelet Ratio Index of ≥1.45 (p=0.003), and Fibrosis-4 score of ≥3.25 (p=0.001). Additionally, the odds of HEV-positive patients developing diabetes mellitus were 3.65 (95% CI 1.40-9.52) times the corresponding odds of HEV-negative patients. A case-control-based histological analysis (n=11 HEV-HCV-positive patients and n=22 HCV-positive patients) showed no significant differences between the groups. CONCLUSIONS: This prevalence is higher than that reported in previous studies of the general population in Brazil. Thus, HEV infection may influence the severity of liver disease and may represent an additional risk of developing diabetes mellitus in patients with HCV infection.

Association of Malaria Infection During Pregnancy With Head Circumference of Newborns in the Brazilian Amazon.

Importance: Malaria during pregnancy is associated with adverse events for the fetus and newborn, but the association of malaria during pregnancy with the head circumference of the newborn is unclear. Objective: To investigate the association of malaria during pregnancy with fetal head growth. Design, Setting, and Participants: Two cohort studies were conducted at the general maternity hospital of Cruzeiro do Sul (Acre, Brazil) in the Amazonian region. One cohort study prospectively enrolled noninfected and malaria-infected pregnant women who were followed up until delivery, between January 2013 and April 2015. The other cohort study was assembled retrospectively using clinical and malaria data from all deliveries that occurred between January 2012 and December 2013. Data analyses were conducted from January to August 2017 and revised in November 2018. Clinical data from pregnant women and anthropometric measures of their newborns were evaluated. A total of 600 pregnant women were enrolled through volunteer sampling (prospective cohort study), and 4697 pregnant women were selected by population-based sampling (retrospective cohort study). After application of exclusion criteria, data from 251 (prospective cohort study) and 232 (retrospective cohort study) malaria-infected and 158 (prospective cohort study) and 3650 (retrospective cohort study) noninfected women were evaluated. Exposure: Malaria during pregnancy. Main Outcomes and Measures: The primary end point was the incidence of altered head circumference in newborns delivered from malaria-infected mothers compared with that from noninfected mothers. Secondary end points included measures of placental pathology relative to newborn head circumference. Results: In total, 4291 maternal-child pairs were analyzed. Among 409 newborns in the prospective cohort study, the mothers of 251 newborns had malaria during pregnancy, infected with Plasmodium vivax, Plasmodium falciparum, or both. Among 3882 newborns in the retrospective cohort study, 232 were born from mothers that had malaria during pregnancy. The prevalence of newborns with a small head (19 [30.7%] in the prospective cohort study and 30 [36.6%] in the retrospective cohort study) and the prevalence of microcephaly among newborns (5 [8.1%] in the prospective cohort study and 6 [7.3%] in the retrospective cohort study) were higher among newborns from women infected with P falciparum during pregnancy. Multivariate logistic regression analyses revealed that P falciparum infection during pregnancy represented a significant risk factor for the occurrence of small head circumference in newborns (prospective cohort study: odds ratio, 3.15; 95% CI, 1.52-6.53; P = .002; retrospective cohort study: odds ratio, 1.91; 95% CI, 1.21-3.04; P = .006). Placental pathologic findings corroborated this association, with more syncytial nuclear aggregates and inflammatory infiltrates occurring in placentas of newborns born with decreased head circumference. Conclusions and Relevance: This study indicates that falciparum malaria during pregnancy is associated with decreased head circumference in newborns, which is in turn associated with evidence of placental malaria.

Association between Traffic Air Pollution and Reduced Forced Vital Capacity: A Study Using Personal Monitors for Outdoor Workers.

BACKGROUND: The effects of outdoor air pollution on lung function in adults are still controversial. OBJECTIVE: Evaluate the effects of exposure to different levels of traffic-generated PM2.5 on workers' lung functions in São Paulo, Brazil. METHODS: To cover a wide range of exposures, 101 non-smoking workers from three occupations (taxi drivers, traffic controllers, and forest rangers) were selected for the study. After clinical evaluation, the participants were scheduled to attend four consecutive weekly visits in which they received a 24-hour personal PM2.5 sampler and had lung function tests measured on the following day. The association between the spirometric variables and the averaged PM2.5 levels was assessed using robust regression models adjusted for age, waist circumference, time at the job, daily work hours, diabetes or hypertension and former smoking habits. RESULTS: Relative to workers in the lowest exposed group (all measures < 25 µg/m3), those with the highest level of exposure (all measures > 39.6 µg/m3) showed a reduction of predicted FVC (-12.2%; CI 95%: [-20.0% to -4.4%]), a marginal reduction of predicted FEV1 (-9.1%; CI 95%: [-19.1% to 0.9%]) and an increase of predicted FEF25-75%/FVC (14.9%; CI 95%: [2.9% to 26.8%]) without changes of FEV1/FVC. CONCLUSIONS: Exposure to vehicular traffic air pollution is associated with a small but significant reduction of FVC without a reduction of FEV1/FVC.

Spatial analysis of urban violence based on emergency room data.

OBJECTIVE: To estimate the spatial intensity of urban violence events using wavelet-based methods and emergency room data. METHODS: Information on victims attended at the emergency room of a public hospital in the city of São Paulo, Southeastern Brazil, from January 1, 2002 to January 11, 2003 were obtained from hospital records. The spatial distribution of 3,540 events was recorded and a uniform random procedure was used to allocate records with incomplete addresses. Point processes and wavelet analysis technique were used to estimate the spatial intensity, defined as the expected number of events by unit area. RESULTS: Of all georeferenced points, 59% were accidents and 40% were assaults. There is a non-homogeneous spatial distribution of the events with high concentration in two districts and three large avenues in the southern area of the city of São Paulo. CONCLUSIONS: Hospital records combined with methodological tools to estimate intensity of events are useful to study urban violence. The wavelet analysis is useful in the computation of the expected number of events and their respective confidence bands for any sub-region and, consequently, in the specification of risk estimates that could be used in decision-making processes for public policies.

Spatial analysis of urban violence based on emergency room data / Análise espacial da violência urbana baseada em dados de pronto-socorro / Análisis espacial de la violencia urbana basada en datos de centros de urgencia

OBJECTIVE: To estimate the spatial intensity of urban violence events using wavelet-based methods and emergency room data. METHODS: Information on victims attended at the emergency room of a public hospital in the city of São Paulo, Southeastern Brazil, from January 1, 2002 to January 11, 2003 were obtained from hospital records. The spatial distribution of 3,540 events was recorded and a uniform random procedure was used to allocate records with incomplete addresses. Point processes and wavelet analysis technique were used to estimate the spatial intensity, defined as the expected number of events by unit area. RESULTS: Of all georeferenced points, 59 percent were accidents and 40 percent were assaults. There is a non-homogeneous spatial distribution of the events with high concentration in two districts and three large avenues in the southern area of the city of São Paulo. CONCLUSIONS: Hospital records combined with methodological tools to estimate intensity of events are useful to study urban violence. The wavelet analysis is useful in the computation of the expected number of events and their respective confidence bands for any sub-region and, consequently, in the specification of risk estimates that could be used in decision-making processes for public policies.

OBJETIVO: Estimar a intensidade espacial de eventos violentos utilizando metodologia estatística baseada em ondaletas (wavelets) e em dados de pronto-socorro. MÉTODOS: Foram analisados dados referentes a vítimas de causas externas atendidas em pronto-socorro municipal localizado na zona Sul da cidade de São Paulo (SP) no período de 1/1/2002 a 11/1/2003. As informações foram obtidas a partir dos registros hospitalares. As 3.540 ocorrências foram localizadas geograficamente e os casos com endereço incompleto foram alocados com base numa escolha aleatória uniforme. Processos pontuais e técnicas de ondaletas foram utilizados para estimar a intensidade espacial, definida como o número esperado de eventos por unidade de área. RESULTADOS: Do total de ocorrências georreferenciadas, 59 por cento foram acidentes e 40 por cento agressões. A intensidade estimada indica que a distribuição espacial dos eventos não é homogênea, concentrando-se em dois distritos e três grandes avenidas localizados na zona Sul da cidade de São Paulo. CONCLUSÕES: A utilização de ondaletas permite obter o número esperado de eventos e respectiva banda de confiança para quaisquer sub-regiões e, conseqüentemente, calcular estimativas dos riscos de ocorrência dos eventos de interesse, fornecendo subsídios para a definição de políticas para o enfrentamento da violência urbana. Dados hospitalares combinados com a metodologia para estimação da intensidade de ocorrência provaram-se úteis para estudar a violência urbana.

OBJETIVO: Estimar la intensidad espacial de eventos violentos utilizando metodología estadística basada en ondaletas (wavelets) y en datos de centros de urgencia. MÉTODOS: Fueron analizados datos referentes a víctimas de causas externas atendidas en centros de urgencias municipales localizados en zonas del sur de la ciudad de São Paulo (sudeste de Brasil) en el período de 1/1/2002 a 11/1/2003. Las informaciones fueron adquiridas a partir de registros hospitalarios. Las 3.540 ocurrencias fueron localizadas geográficamente en los casos con dirección incompleta fueron localizados en base en una elección aleatoria uniforme. Procesos puntuales y técnicas de ondaletas fueron utilizados para estimar la intensidad espacial, definida como el número esperado de eventos por unidad de área. RESULTADOS: Del total de ocurrencias georreferenciadas, 59 por ciento fueron accidentes y 40 por ciento agresiones. La intensidad estimada indica que la distribución espacial de los eventos no es homogénea, concentrándose en dos distritos y tres grandes avenidas localizadas en la zona sur de la ciudad de São Paulo. CONCLUSIONES: La utilización de ondaletas permite obtener el número esperado de eventos y respectiva banda de confianza para cualquier sub-región y, consecuentemente, calcular estimativas de los riesgos de ocurrencia de los eventos de interés, proporcionando subsidios para la definición de políticas para el enfrentamiento de la violencia urbana. Datos hospitalarios combinados con la metodología para estimar la intensidad de ocurrencia probaron ser útiles para estudiar la violencia urbana.

Cardiovascular rehabilitation of patients with ischemic heart disease undergoing medical treatment, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting.

OBJECTIVE: To evaluate the occurrence of death and myocardial infarction in subgroups of coronary artery disease patients with hemodynamically significant coronary stenoses undergoing treatment in a cardiovascular rehabilitation program and considered severely ill for: a) not having undergone intervention treatment; b) presenting signs of myocardial ischemia; c) presenting multivessel occlusive disease. METHODS: Retrospective cohort study of 381 patients presented previous coronary angiography showing hemodynamically significant coronary stenoses, for which, because of the anatomic bias, intervention treatment was indicated. The patients were categorized according to the presence or absence of intervention treatment; presence or absence of ischemia in the exercise test; and number of critical coronary stenoses. Statistical analysis was performed using the Kaplan-Meier and logistic regression methods. RESULTS: Survival probability was not different when patients undergoing medical treatment were compared to those undergoing previous intervention treatment (OR 0.813; 95% CI; 0.366-1.809); with and without evidence of ischemia in the exercise test (OR 0.785; 95% CI; 0.366-1.684); and with one-vessel coronary artery disease and with more-than-one-vessel coronary artery disease (OR 0.824, 95% CI; 0.377-1.798). CONCLUSION: In this cohort study, no unfavorable outcome was observed in the subgroups comprised of medically treated patients, with evidence of myocardial ischemia and with multivessel coronary artery disease.

Reabilitação cardiovascular de portadores de cardiopatia isquêmica submetidos a tratamento clínico, angioplastia coronariana transluminal percutânea e revascularização cirúrgica do miocárdio / Cardiovascular rehabilitation of patients with ischemic heart disease undergoing medical treatment, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting

OBJETIVO: Avaliar a ocorrência de morte e infarto do miocárdio em portadores de obstruções coronarianas hemodinamicamente significativas, participantes de programa de reabilitação cardiovascular, considerados mais graves por: a) não terem sido submetidos a tratamento intervencionista; b) apresentarem sinais de isquemia miocárdica; e c) apresentarem doença obstrutiva multiarterial. MÉTODOS: Coorte retrospectiva de 381 pacientes, com cinecoronariografia evidenciando obstruções hemodinamicamente significativas, o que, pelo viés anatômico, justificaria tratamento intervencionista. Os pacientes foram categorizados pela presença ou ausência de tratamento intervencionista, presença ou ausência de isquemia no teste ergométrico, e número de obstruções coronarianas críticas. A análise estatística foi feita pelos métodos de Kaplan-Meier e regressão logística. RESULTADOS: A probabilidade de sobrevida não diferiu quando foram comparados os pacientes submetidos a tratamento clínico com os submetidos a tratamento intervencionista prévio (odds ratio [OR] = 0,813; intervalo de confiança [IC] 95 por cento = 0,366-1,809), com evidência de isquemia e sem evidência de isquemia no teste de esforço (OR = 0,785; IC 95 por cento = 0,366-1,684), e os com obstrução em uma artéria coronária em relação aos com obstruções em mais de uma artéria coronária (OR = 0,824; IC 95 por cento = 0,377-1,798). CONCLUSÃO: Nesta coorte, não ocorreu evolução desfavorável nos subgrupos formados por pacientes mantidos em tratamento clínico, com evidência de isquemia miocárdica e com doença coronariana multiarterial.

OBJECTIVE: To evaluate the occurrence of death and myocardial infarction in subgroups of coronary artery disease patients with hemodynamically significant coronary stenoses undergoing treatment in a cardiovascular rehabilitation program and considered severely ill for: a) not having undergone intervention treatment; b) presenting signs of myocardial ischemia; c) presenting multivessel occlusive disease. METHODS: Retrospective cohort study of 381 patients presented previous coronary angiography showing hemodynamically significant coronary stenoses, for which, because of the anatomic bias, intervention treatment was indicated. The patients were categorized according to the presence or absence of intervention treatment; presence or absence of ischemia in the exercise test; and number of critical coronary stenoses. Statistical analysis was performed using the Kaplan-Meier and logistic regression methods. RESULTS: Survival probability was not different when patients undergoing medical treatment were compared to those undergoing previous intervention treatment (OR 0.813; 95 percent CI; 0.366-1.809); with and without evidence of ischemia in the exercise test (OR 0.785; 95 percent CI; 0.366-1.684); and with one-vessel coronary artery disease and with more-than-one-vessel coronary artery disease (OR 0.824, 95 percent CI; 0.377-1.798). CONCLUSION: In this cohort study, no unfavorable outcome was observed in the subgroups comprised of medically treated patients, with evidence of myocardial ischemia and with multivessel coronary artery disease.

Effects of Nd:YAG laser on enamel microhardness and dental plaque composition: an in situ study.

OBJECTIVE: This study evaluated Knoop microhardness (KHN) and dental plaque composition of human enamel irradiated with Nd:YAG laser and subjected to in situ cariogenic challenge. BACKGROUND DATA: Although in vitro studies have shown that Nd:YAG laser irradiation results in a reduction of enamel mineral loss after acid challenge, this hypothesis has not been tested using an in situ caries model. METHODS: Acrylic devices containing lased and non-lased human enamel slabs were used for 28 days by eight subjects highly colonized by S. mutans. Devices were immersed in a sucrose solution (20%) eight times daily in order to better simulate the cariogenic challenge. RESULTS: After the experimental period, no differences in dental plaque composition were observed between lased and non-lased enamel slabs indicating that all slabs were exposed to equivalent cariogenic challenges. Cross sections of enamel slabs were then measured for Knoop microhardness at 10, 20, 40, 60, 80, 120, and 180 microm in depth from the outer exposed surface. Un-lased enamel slabs not subjected to the in situ cariogenic challenge were also used as control. Enamel slabs from the two in situ groups exhibited lower hardness when compared to control. Lased enamel showed higher hardness values up to 60 microm in depth than the un-lased enamel exposed to in situ cariogenic challenge. CONCLUSION: The results suggest that the irradiation of Nd:YAG laser of human enamel appears to be effective for increasing enamel hardness and thus decreasing the effect of acid attack.

Adhesive systems used for sealing contaminated surfaces: a microleakage evaluation.

The aim of this study was to compare two adhesive systems (OptiBond FL and OptiBond SOLO) used as a sole material for sealing pit and fissures on contaminated surfaces with respect to microleakage. After acid etching, 56 sound teeth were contaminated with 1microl of plasma and randomly divided into 8 groups (n = 7). The adhesives were light activated under two conditions (Optilux VCL-403 and VCL-500) for 30 s. Each specimen was exposed to one of the following aging treatments: thermal (4,000 X at 5-55 degrees C for 60 s) plus load cycling (225,000 X with 83.3 N) or thermal plus load and pH cycling (mineralizing/demineralizing solutions). Then, they were immersed in a 50% AgNO3 aqueous solution, sectioned twice and had dye penetration measured through digitized images. ANOVA methods were used to assess the main effects of the factors as well as their interactions. The results indicated a significant difference between the adhesive systems (p < 0.05), suggesting that OptiBond FL has a better performance with respect to microleakage and could be used as a sealing material in accidentally moist or contaminated surfaces.

Adhesive systems used for sealing contaminated surfaces: a microleakage evaluation

O propósito deste estudo foi comparar dois sistemas adesivos (OptiBond FLTM e OptiBond SOLOTM) utilizados como material único para selar superfícies oclusais contaminadas com relação à infiltração marginal. Após condicionamento ácido, 56 dentes hígidos foram contaminados com 1 µl de plasma e aleatoriamente divididos em 8 grupos (n = 7). Os adesivos foram fotoativados por 30 s sob duas condições (Optilux VCL-403TM e VCL-500TM). Cada espécime foi exposto a um de dois tratamentos de envelhecimento: ciclos térmicos (4.000 x a 5-55°C por 60 s) mais ciclos mecânicos (225.000 x com carga de 83,3 N); ou ciclos térmicos, mecânicos e de pH (soluções mineralizante/desmineralizante). Os espécimes foram imersos em solução aquosa de AgNO3 a 50%, secionados, e a penetração do corante foi medida em imagem digitalizada. Usou-se ANOVA para determinar os principais efeitos dos fatores e suas interações. Os resultados indicaram diferença significante entre os adesivos (p < 0,05), sugerindo que o OptiBond FLTM apresenta um desempenho melhor com relação à microinfiltração e poderia ser indicado como material único para selamento em condições de umidade ou contaminação acidental.

Effect of thermal cycling and filling technique on leakage of composite resin restorations

O objetivo deste estudo foi avaliar o efeito de duas técnicas incrementais de inserção na infiltração de restaurações de resinas compostas com módulos de elasticidade distintos e contração de polimerização semelhante. Para isto, foram preparadas 80 cavidades Classe V (4x4x2 mm) em incisivos bovinos que foram restauradas de modo aleatório com Z-250 (Z) ou Durafill VS (D) + Single Bond em incrementos axiais (a) ou oblíquos (o). As restaurações foram divididas em dois grupos: Não Envelhecidas - N (4 h em água destilada a 37° C) e Envelhecidas ù E (1 semana de armazenagem em água a 37° C + 1000 x - 5°-55°C / 1 min de imersão). Os espécimes foram recobertos com duas camadas de esmalte cosmético de modo que apenas as margens das restaurações ficassem expostas ao nitrato de prata (2h) seguido de imersão em revelador (8h) sob luz fluorescente. Posteriormente, eles foram secionados duas vezes no sentido vestíbulo-lingual, as superfïcies expostas (4) foram digitalizadas (Vidcap) e a penetração do nitrato de prata medido (ImageLab) nas paredes incisal e gengival. Os dados foram analisados por análise de variância de três fatores (Resina, Técnica de Inserção e Envelhecimento) separadamente para as paredes incisal e gengival. Resina e Envelhecimento foram significativos. A resina composta de micropartículas mostrou maior infiltração que a híbrida. A técnica de inserção influenciou a infiltração marginal dependendo da resina e do emprego ou não de ciclos térmicos.

Effect of thermal cycling and filling technique on leakage of composite resin restorations.

The objective of this study was to evaluate in vitro the effect on leakage of two incremental filling techniques and two composite resins with different elastic modulus and similar polymerization shrinkage. Eighty Class V cavities (4x4x2mm) were prepared in bovine incisors and were randomly restored with Z-250 (Z) or Durafill VS (D) + Single Bond in axial (a) or oblique (o) increments. The restorations were divided into two groups: Not Aged - N (4-hour-storage in water at 37ºC) and Aged - A (1-week storage in water at 37ºC + 1000 x - 5º-55ºC / 1-min dwell time). The specimens were covered with 2 coats of nail varnish so that only the restoration margins were exposed to silver nitrate 50% (2h) and developed under fluorescent light (8h). After they were sectioned twice in buccal-lingual direction, the four exposed surfaces were digitized (Vidcap) and the silver nitrate penetration was measured (ImageLab) at the incisal and gingival walls. Data were analyzed by a 3-way ANOVA (Resin, Filling Technique and Aging) separately for incisal and gingival walls (alpha=0.05). Resin and Aging were statistically significant either for the incisal and the gingival walls. The microfill composite resin infiltrated more than the hybrid composite. The thermal cycling caused an overall increase in silver nitrate penetration. The filling technique affected leakage depending on the composite resin and aging regimen.

Effectiveness of low cost toothbrushes, with or without dentifrice, in the removal of bacterial plaque in deciduous teeth.

The main objective of this study was to compare the effectiveness of a low cost toothbrush ("monoblock") to that of a conventional toothbrush with and without addition of dentifrice with respect to the removal of dental plaque. Thirty-two 4- to 6-year-old children took part in this study: they were evaluated under four experimental conditions defined by the combinations of the values of two factors, toothbrush (conventional or monoblock) and use of dentifrice (with or without). The effectiveness of the treatments was defined in terms of the reduction of a bacterial plaque index evaluated before and after toothbrushing. No statistically significant differences were detected between the two types of toothbrushes with respect to the reduction of the bacterial plaque index. Similarly, there were no statistical evidences that the use of dentifrice improves the mechanical control of dental plaque. These results are important from a public health point of view, specially in developing countries, where the dissemination of educational and preventive techniques of low cost are fundamental.

Effectiveness of low cost toothbrushes, with or without dentifrice, in the removal of bacterial plaque in deciduous teeth

O principal objetivo deste estudo é comparar a efetividade de uma escova dental de baixo custo (monobloco), com uma escova convencional, com ou sem a adiçäo de dentifrício, em relaçäo à remoçäo da placa dental. Participaram deste estudo trinta e duas crianças de 4 a 6 anos de idade, que foram avaliadas sob quatro condições experimentais, definidas pela combinaçäo de dois fatores: escova dental (convencional ou monobloco) e uso de dentifrício (sim ou näo). A efetividade dos tratamentos foi definida em termos de reduçäo de índice de placa bacteriana, avaliado antes e após a escovaçäo. Näo foram encontradas diferenças estatísticamente significante entre os dois tipos de escovas no que diz respeito à reduçäo de placa bacteriana. Similarmente, näo houve evidências estatísticas de que o uso de dentifrício aumenta o controle mecânico da placa. Estes resultados säo importantes do ponto de vista de saúde pública, principalmente em países em desenvolvimento, onde a dissiminaçäo de técnicas educacionais e preventivas de baixo custo säo fundamentais

Bond strength between polymer resin-based cement and porcelain-dentin surfaces: influence of polymerization mode and early cyclic loading / Força adesiva entre superfícies de polímero de resina-cimento de base e dentina-porcelana: influência do modo de polimerização e carga cíclica

Purpose: The objective of this study was to verify the influence of resin cement polymerization mode and early cyclic loading on the bond strength of porcelain-dentin specimens. Materials and Methods: Two cementation systems, ChoiceOne-Step and RelyX ARCSingle Bond, were tested. Porcelain truncated cones were bonded into cavities prepared in sections of bovine root dentin. Each system was tested with the resin cement in dual-cure and self-cure mode (with and without photoactivation, respectively). Half of the specimens were load cycled 15 minutes after cement mixing (60 N, 20 times). The other half were not submitted to mechanical loading (control). After 24-hour storage in distilled water (37ºC), the extrusion shear test was performed. Data were analyzed by three-way ANOVA. Results: With both systems, some specimens built with the cement in self-cure mode debonded during cyclic loading (RelyX ARCSingle Bond 47 percent; ChoiceOne-Step 13 percent). No significant system effects were detected. Mean bond strength under the dual-cure mode (13.4 MPa, SD 3.6) was significantly higher than the corresponding mean for the selfcured specimens (5.7 MPa, SD 2.6). No reduction in bond strength was observed for the specimens that survived the early cyclic loading. Conclusion: Resin cements in dual-cure mode presented higher bond strengths than self-cured materials. Early load cycling caused debonding of some self-cured specimens. However, the bond strength of the survivor specimens was not affected by load cycling

Microleakage in class II composite resin restorations: total bonding and open sandwich technique.

PURPOSE: The objective of this in vitro study was to evaluate gingival microleakage in Class II total bond resin restorations in comparison to open sandwich technique restorations using different materials. MATERIALS AND METHODS: Forty-eight human molar teeth were disinfected and stored in a 0.9% saline solution. In each tooth, two standardized Class II cavities (3 mm x 6 mm x 2 mm) were prepared with the gingival cavosurface margins located 1 mm below the cementoenamel junction. The teeth were divided into 4 equally sized groups (n = 12), and the proximal boxes were treated as follows: in Group 1, no base material was used and the cavity was restored using SyntacSprint (SS) and Tetric Ceram (TC); in Groups 2, 3, and 4 the gingival portion of the cavity was restored with different base materials (Group 2, Dyract; Group 3, Vitremer; Group 4, Chelon-fil) prior to the placement of the composite resin. After a storage time of 7 days, the restorations were finished and polished. Then, specimens were submitted to thermocycling (500 cycles, 5 degrees C to 55 degrees C, 15 s dwell time) and immersed in a 0.5% methylene blue solution for 24 h. After washing, they were sectioned in a mesio-distal direction. Each restoration was evaluated under a stereomicroscope at 20x by 2 examiners and scored on a 0 to 3 scale according to the marginal leakage. Kappa statistics were used to evaluate the agreement between the examiners. Given the ordinal nature of the scoring system, data were submitted to a nonparametric repeated measures ANOVA. The results were confirmed with a parametric repeated measures ANOVA. RESULTS: Significant differences (p < 0.001) among the four groups with respect to dye penetration were detected, with the association Vitremer/Tetric showing the best results. CONCLUSION: The use of Vitremer in the open sandwich technique presents the lowest degree of microleakage among the treatments considered in this study.

Tensile bond strength of adhesive systems--effects of primer and thermocycling.

The objective of this study was to evaluate the effects of primer and thermocycling on the bond strength of multi-purpose adhesive systems applied to enamel, under tensile stress. The following bonding systems were applied, according to the manufacturers' instructions, on unground enamel buccal surfaces of 96 premolars, with or without the application of primer: Scotchbond MP, OptiBond FL, Amalgambond Plus and OptiBond (dual-cure). A composite resin (Z100, 3M) was applied and light-cured in a cast metal hollow cone, which was previously fixed to the enamel surfaces. Half of the sample was subjected to 3,000 thermocycles (5-37 degrees C; 37-55 degrees C, dwell time of 60 s), and the other half was stored in water at 37 degrees C for the same period. The data were treated by means of ANOVA and no significant effects were detected, which indicates that tensile bond strength was not affected by the adhesive systems, application of primer or thermocycling.

Tensile bond strength of adhesive systems - effects of primer and thermocycling / Resistência à traçäo de sistemas adesivos - efeitos do \"primer\" e dos ciclos térmicos

O objetivo desta pesquisa foi o de verificar o efeito do "primer" e dos ciclos térmicos na resistência da uniäo entre adesivos multiuso e esmalte dental, sob ensaios de traçäo. Os seguintes sistemas adesivos foram aplicados, de acordo com as instruçöes dos fabricantes, na superfície vestibular (sem desgaste) de 96 pré-molares com ou sem a aplicaçäo prévia do "primer": Scotchbond MP, OptiBond FL, Amalgambond Plus e OptiBond -"dual cure". Após a aplicaçäo do sistema adesivo, foi confeccionado um cone de resina composta (Z100, 3M), e fotoativado dentro de uma molde metálico. Metade do total de espécimes foi submetida a 3.000 ciclos térmicos (5-37ºC; 37-55ºC, 60s de imersäo); a outra metade permaneceu imersa em água a 37ºC pelo mesmo tempo dispensado no procedimento anterior. Os dados foram submetidos a uma análise de variância (p=0,05) e nenhum efeito significante foi detectado, indicando que a resistência de uniäo näo foi afetada pelo sistema adesivo, pela aplicaçäo do "primer"ou pelos ciclos térmicos

Influência de cargas cíclicas imediatas na resistência da uniäo porcelana/dentina: estudo premilinar / Influence or early cyclic loading on the strength of the porcelain/dentin union: preliminary study

O objetivo deste estudo foi verificar a influência de cargas cíclicas imediatas na resistência da uniäo porcelana/dentina em ensaio de cisalhamento por extrusäo. Os sistemas adesivos utilizados foram o C&BTM/One-Step© (CB) e o RelyXTM ARC/Single Bond© com (RX) e sem ativaçäo física (RXQ). Foram cimentadas 50 peças tronco-cônicas de porcelana feldspática em cavidades preparadas em seçöes de dentina radicular bovina. Para cada sistema adesivo, um grupo (n = 5) recebeu 20 cargas cíclicas de 58,8 N (6 kgf), 15 min após o início do preparo do cimento; um segundo grupo recebeu as cargas após 2 h; e um teceiro grupo (controle) näo recebeu cargas. Para o sistema RX, usado no modo "dual cure", foi testado também um grupo no qual as cargas eram aplicadas logo após a fotoativaçäo. O teste de cisalhamento por extrusäo foi realizado após 24 h de armazenamento em água destilada a 37ºC. Observou-se rompimento da uniäo durante aplicaçäo das cargas em alguns corpos-de-prova dos sistemas CB e ao RXQ. Os dados referentes aos corpos-de-prova que resistiram às cargas repetitivas imediatas foram tratados por análise de variância, permitindo concluir que o RX teve desempenho superior ao CB e RXQ, e que o emprego de cargas cíclicas näo diminuiu os valores de resistência da uniäo sob ensaios de cisalhamento por extrusäo