Influence of sodium hypochlorite and edta on the microtensile bond strength of a self-etching adhesive system

Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials. OBJECTIVE: The purpose of this study was to evaluate the microtensile bond strength (µTBS) of a self-etching adhesive system to dentin irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). MATERIAL AND METHODS: Thirty human third molars were sectioned 3 mm below the occlusal surface, polished with 600- to 1200-grit silicon carbide papers, and randomly divided into 3 groups: G1 (control): no irrigating solution; G2: 1% NaOCl; and G3: 1% NaOCl followed by the application of 17% EDTA. The specimens received the self-etching adhesive system (XENO III - Dentsply), restored with microhybrid composite resin (Z250 - 3M ESPE), sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. RESULTS: Mean µTBS values and standard deviations in MPa were: G1 = 11.89 ± 4.22; G2 = 19.41 ± 5.32; G3 = 11.34 ± 4.73. 1% NaOCl increased the adhesive resistance significantly (p<0.001/F=22.5763). The application of 1% NaOCl/17% EDTA resulted in statistically similar µTBS to the control group. CONCLUSIONS: None of the irrigants affected negatively the µTBS of XENO III to dentin. The use of 1% NaOCl alone resulted in higher bond strength than the other treatments. The combination of 1% NaOCl and 17% EDTA produced similar bond strength to that of untreated dentin.

Tissue inflammatory response to implantation of calcium hydroxide and iodoform in the back of rats

PURPOSE: This study evaluated the inflammatory reaction caused by the implantation of iodoform and calcium hydroxide in the back of rats. These drugs may be used as intracanal dressings to eliminate residual bacteria of the root canal system. METHODS: Twenty albinic rats (Rattus norvegicus, var Wistar) were divided into four groups: control group 1 (CG1) had normal skin; control group 2 (CG2) had wounded tissue without drugs; in groups 3 and 4, iodoform (IG) and calcium hydroxide (CHG) were inserted into the wounds, respectively. After 3, 5 and 11 days, slices of the implanted areas were macroscopically and microscopically observed regarding to their qualitative and quantitative aspects. RESULTS: In the macroscopical analysis, the CHG showed a large area of necrosis and swelling, which progressively decreased; in the IG the presence of iodoform surrounded by normal tissue was observed. The qualitative and quantitative histological analysis showed that IG promoted a shorter delay in the inflammatory response than the CHG. CONCLUSION: The inflammatory reaction for iodoform had a peak period five days after the drug insertion. By comparison, calcium hydroxide showed a very large area of necrosis that could only be partially eliminated after eleven days.

Pulp capping materials exert an effect on the secretion of IL-1β and IL-8 by migrating human neutrophils

Pulp repair is a complex process whose mechanisms are not yet fully understood. The first immune cells to reach the damaged pulp are neutrophils that play an important role in releasing cytokines and in phagocytosis. The objective of this study was to analyze the effect of different pulp-capping materials on the secretion of interleukin-1 beta (IL-1β) and interleukin-8 (IL-8) by migrating human neutrophils. Neutrophils were obtained from the blood of three healthy donors. The experimental groups were calcium hydroxide [Ca(OH)2], an adhesive system (Single Bond), and mineral trioxide aggregate (MTA). Untreated cells were used as control. Transwell chambers were used in performing the assays to mimic an in vivo situation of neutrophil chemotaxis. The pulp-capping materials were placed in the lower chamber and the human neutrophils, in the upper chamber. The cells were counted and the culture medium was assayed using ELISA kits for detecting and quantifying IL-1β and IL8. The data were compared by ANOVA followed by Tukey's test (p < 0.05). The secretion of IL-8 was significantly higher in all groups in comparison to the control group (p < 0.05). The adhesive system group showed higher IL-8 than the MTA group (p < 0.05). The secretion of IL-1β was significantly greater only in the MTA group (p < 0.001). It was concluded that only MTA is able to improve the secretion of IL-1β, and all materials tested increased IL-8 secretion. These results combined with all the other biological advantages of MTA indicate that it could be considered the material of choice for dental pulp capping.

Do the origins of primary teeth affect the bond strength of a self-etching adhesive system to dentin?

The aim of this in vitro study was to evaluate the tensile bond strength of a self-etching adhesive system to three different dentinal substrates. Primary molar teeth that had been recently exfoliated (RE), with unknown time of exfoliation (UT), and extracted due to prolonged retention (PR) were used for this investigation. Ten primary molar teeth of each group were cut in the middle following the mesio-distal direction, creating a total of twenty specimens per group. The specimens were included in acrylic resin and had a flat dentin surface exposed. The self-etching adhesive system was applied to this surface and a 3-millimeter high cone with diameter of 2 mm in the adhesion area was constructed using composite resin. The specimens were stored in distilled water at 37ºC for 24 hours. Fifteen specimens of each substrate were used for the tensile bond test (n = 15) and 5 had the interface analyzed by scanning electron microscopy (SEM). The data was examined by one-way ANOVA and presented no significant differences between groups (p = 0.5787). The mean values obtained for RE, UT and PR were 18.39 ± 9.70, 19.41 ± 7.80, and 23.30 ± 9.37 MPa, respectively. Any dentinal substrates of primary teeth studied are safe for tensile bond strength tests with adhesive systems.

Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions

There are many studies that compare the accuracy of multislice (MSCT) and cone beam (CBCT) computed tomography for evaluations in the maxillofacial region. However, further studies comparing both acquisition techniques for the evaluation of simulated mandibular bone lesions are needed. The aim of this study was to compare the accuracy of MSCT and CBCT in the diagnosis of simulated mandibular bone lesions by means of cross sectional images and axial/MPR slices. Lesions with different dimensions, shape and locularity were produced in 15 dry mandibles. The images were obtained following the cross sectional and axial/MPR (Multiplanar Reconstruction) imaging protocols and were interpreted independently. CBCT and MSCT showed similar results in depicting the percentage of cortical bone involvement, with great sensitivity and specificity (p < 0.005). There were no significant intra- or inter-examiner differences between axial/MPR images and cross sectional images with regard to sensitivity and specificity. CBCT showed results similar to those of MSCT for the identification of the number of simulated bone lesions. Cross sectional slices and axial/MPR images presented high accuracy, proving useful for bone lesion diagnosis.

Comparison of the fracture torque of different Brazilian mini-implants

This study evaluated fracture torque by torsion, in relation to the length and diameter of orthodontic mini-implants, to demonstrate their viability for clinical and experimental use based on the torque recommended by the manufacturers. The fractures at the moment of insertion, whose incidence in the literature is around 4%, are principally due to excessive force and the inability of the implant to resist rotational forces. Thirty orthodontic mini-implants of three commercial brands available in Brazil (Neodent 1.6 x 9 mm, Dentoflex 1.6 x 9 mm and Kopp 1.6 x 9 mm) were attached to a device made specifically for this research, leaving the mini-implants with sufficient stability. The miniimplants were submitted to torsion torque, using a digital torque wrench, until their breaking point. The values obtained with the test were submitted to analysis of variance and the Tukey test. The mean values of mini-implant ruptures were 26 N.cm for group A (Dentoflex), 25.4 N. cm for group B (Kopp) and 32.8 N.cm for group C (Neodent). From the Tukey test we could observe that the relationships between the means of the Dentoflex and Neodent groups, and between the Kopp and Neodent groups, were significant. Between the Dentoflex and Kopp groups, significance was nonexistent. All the values found in our research for fracture torque were higher than the limits recommended by the manufacturers for clinical use in orthodontics. The highest values were found in the Neodent group.

Influence of specimens' design and manufacturing process on microtensile bond strength to enamel: laboratory and FEA comparison

This study evaluated the effect of specimens' design and manufacturing process on microtensile bond strength, internal stress distributions (Finite Element Analysis - FEA) and specimens' integrity by means of Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy (LCM). Excite was applied to flat enamel surface and a resin composite build-ups were made incrementally with 1-mm increments of Tetric Ceram. Teeth were cut using a diamond disc or a diamond wire, obtaining 0.8 mm² stick-shaped specimens, or were shaped with a Micro Specimen Former, obtaining dumbbell-shaped specimens (n = 10). Samples were randomly selected for SEM and LCM analysis. Remaining samples underwent microtensile test, and results were analyzed with ANOVA and Tukey test. FEA dumbbell-shaped model resulted in a more homogeneous stress distribution. Nonetheless, they failed under lower bond strengths (21.83 ± 5.44 MPa)c than stick-shaped specimens (sectioned with wire: 42.93 ± 4.77 MPaª; sectioned with disc: 36.62 ± 3.63 MPa b), due to geometric irregularities related to manufacturing process, as noted in microscopic analyzes. It could be concluded that stick-shaped, nontrimmed specimens, sectioned with diamond wire, are preferred for enamel specimens as they can be prepared in a less destructive, easier, and more precise way.

Tendência e diferenciais socioeconômicos da mortalidade por câncer de colo de útero no Estado do Paraná (Brasil), 1980-2000

O objetivo deste artigo é discutir a evolução da mortalidade por câncer de colo de útero no Estado do Paraná entre 1980 e 2000 e analisar seus diferenciais socioeconômicos em cada região. Taxas de mortalidade ajustadas por idade foram calculadas para as 22 regionais de saúde do Estado a cada ano. Análises comparativas avaliaram indicadores socioeconômicos associados com regiões que apresentaram tendência estacionária e crescente de mortalidade. A mortalidade por câncer de colo uterino cresceu no Estado como um todo a uma taxa de 1,68% (IC 1,20-2,17) ao ano. A maior parte das regiões apresentou tendência estacionária de mortalidade por câncer de colo de útero. As regionais com tendência de aumento na mortalidade apresentaram proporção significativamente mais elevada de analfabetismo (p<0,001) e de adultos (15 anos ou mais) com menos de 4 anos de estudo (p=0,001), e renda per capita (p=0,025) e IDH (p=0,023) inferiores. Houve tendência de aumento na mortalidade em todo o Estado; as regiões que contribuíram para o aumento experimentaram piores indicadores socioeconômicos.

An in vitro comparison of nickel and chromium release from brackets

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%). International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS) or artificial plaque fluid (PF) over a period of 28 days at 37ºC. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (µg L-1 per week) varied between groups from "bellow detection limits" to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (µg L-1 per week) were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.

Evaluation of recycled tiles and OSB ceiling materials in closed broiler house prototypes

This study aimed at evaluating the thermal performance of a modular ceiling system for poultry houses. The reduced- and distorted-scale prototypes used ceiling modules made of reforested wood and were covered with recycled long-life package tiles. The following parameters were measured for 21 days: tile internal surface temperature (ST), globe temperature and humidity index (WBGT), and radiant heat load (RHL). Measurements were made at times of highest heat load (11:00 am, 13:00 pm, and 03:00 pm). Collected data were analyzed by "R" statistics software. Means were compared by multiple comparison test (Tukey) and linear regression was performed, both at 5% significance level. The results showed that the prototype with the ceiling was more efficient to reduce internal tile surface temperature; however, this was not sufficient to provide a comfortable environment for broilers during the growout. Therefore, other techniques to provide proper cooling are required in addition to the ceiling.

Contribuições para análise da política de saúde auditiva no Brasil

OBJETIVO: Realizar o levantamento do quantitativo dos procedimentos relacionados à adaptação de aparelho de amplificação sonora individual (AASI) incluídos na Tabela do Sistema Único de Saúde (Tabela SUS). MÉTODOS: Os dados sobre os procedimentos relacionados à adaptação de AASI incluídos na Tabela SUS foram levantados no site www.datasus.gov.br. Após o levantamento desses dados, foi realizada a organização e a análise descritiva da produção dos atendimentos ambulatoriais registrados pelos serviços de saúde auditiva do Brasil, durante o período de novembro de 2004 a julho de 2010. Os dados foram analisados estatisticamente. RESULTADOS: Quanto aos procedimentos relacionados à dispensação de AASI no território nacional no âmbito da saúde auditiva, em 2006, a terapia fonoaudiológica ultrapassou o quantitativo obtido pela adaptação de AASI e, o acompanhamento fonoaudiológico, por sua vez, foi pouco realizado no país. Os AASI com tecnologias B e C vem sendo mais adaptados do que os AASI de tecnologia A e a realização de medida com microfone sonda ou acoplador de 2cc na adaptação dos AASI é pouco realizada em comparação ao ganho funcional. CONCLUSÃO: Houve grandes avanços na atenção ao deficiente auditivo no país, mas é necessário aprimorar o acompanhamento dos usuários de AASI, e revisar procedimentos como medidas com microfone sonda e tecnologias dos AASI.

Vancomycin use in a brazilian teaching hospital: comparison with the Hospital Infection Controlpractices Advisory Committee Guidelines (HICPAC)

This study describes vancomycin prescribing patterns in an average complexity hospital and compare the guidelines proposed by the Hospital Infection Control Practices Advisory Committee (HICPAC). The study was conducted in a 256-bed secondary-care hospital. Data were collected of all patients given vancomycin from March 2003 to February 2004, using a standardized chart-extraction form designed. Appropriate and inappropriate use was reviewed according to the Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines on prudent vancomycin use. Out of 118 prescriptions, 95 (80.5%) were considered appropriate. Out of these 95 orders, 77 (81.1%) were administered for empiric treatment of suspected Gram-positive infections, 17 (17.9%) were administered for treatment of proven Gram-positive infections (76.5% identified as Staphyloccocus aureus-like agents) and 1 (1.0%) for beta-lactam allergy. The majority of the patients (96.6%) had recently used an antimicrobial medication (3 months). The mean pre-treatment hospitalization period was 11±10 days. Out of the 118 treatments, 67 (56.8%) were for nosocomial infections. The more frequent indications for vancomycin use were pneumonia (48.3%) and primary sepsis (18.6%), accounting for more than 66% of all treatments. No restriction policy was suggested because vancomycin use was considered adequate in the majority of the treatment cases. The broad empiric use of this antimicrobial was greater than expected in the institution and its use should be revised.

Renin angiotensin system and cardiac hypertrophy after sinoaortic denervation in rats

OBJECTIVE: The aim of this study was to evaluate the role of angiotensin I, II and 1-7 on left ventricular hypertrophy of Wistar and spontaneously hypertensive rats submitted to sinoaortic denervation. METHODS: Ten weeks after sinoaortic denervation, hemodynamic and morphofunctional parameters were analyzed, and the left ventricle was dissected for biochemical analyses. RESULTS: Hypertensive groups (controls and denervated) showed an increase on mean blood pressure compared with normotensive ones (controls and denervated). Blood pressure variability was higher in denervated groups than in their respective controls. Left ventricular mass and collagen content were increased in the normotensive denervated and in both spontaneously hypertensive groups compared with Wistar controls. Both hypertensive groups presented a higher concentration of angiotensin II than Wistar controls, whereas angiotensin 1-7 concentration was decreased in the hypertensive denervated group in relation to the Wistar groups. There was no difference in angiotensin I concentration among groups. CONCLUSION: Our results suggest that not only blood pressure variability and reduced baroreflex sensitivity but also elevated levels of angiotensin II and a reduced concentration of angiotensin 1-7 may contribute to the development of left ventricular hypertrophy. These data indicate that baroreflex dysfunction associated with changes in the renin angiotensin system may be predictive factors of left ventricular hypertrophy and cardiac failure.

Classificação de sistemas meteorológicos e comparação da precipitação estimada pelo radar e medida pela rede telemétrica na bacia hidrográfica do alto Tietê

Foram analisadas características da precipitação estimada a partir de 145.194 campos de refletividade, de um total de 827 dias entre 1998 e 2003, obtidos do Radar Meteorológico de São Paulo (RSP). Os eventos foram classificados de acordo com intensidades de precipitação; em Convectivos (EC) e Estratiformes (EE). Quanto à morfologia, cinco tipos de sistemas foram identificados; Convecção Isolada (CI), Brisa Marítima (BM), Linhas de Instabilidade (LI), Bandas Dispersas (BD) e Frentes Frias (FF). Eventos convectivos dominam na primavera e verão e estratiformes no outono e inverno. A CI e a BM tiveram maiores picos de atuação entre outubro e março enquanto as FF de abril a setembro. BD atuam durante todo o ano e as LI só não foram observadas nos meses de junho e julho. Uma comparação pontual entre a precipitação medida pela telemetria e estimada com o radar foi realizada e, mostrou haver, na maioria dos casos, um viés positivo do RSP, para acumulações de 10, 30 e 60 minutos. Com o objetivo de integrar as estimativas de precipitação do radar com as medidas da rede telemétrica, por meio de uma análise objetiva estatística, foram obtidas dos campos de precipitação do radar as estruturas das correlações espaciais em função da distância para acumulações de chuva de 15, 30, 60 e 120 minutos para os cinco tipos de sistemas precipitantes que foram caracterizados. As curvas das correlações espaciais médias de todos os eventos de precipitação de cada sistema foram ajustadas por funções polinomiais de sexta ordem. Os resultados indicam diferenças significativas na estrutura espacial das correlações entre os sistemas precipitantes.

Comparison of radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa forel in two culture media

In vitro culture of the mutualistic fungus of leaf-cutting ants is troublesome due to its low growth rate, which leads to storage problems and contaminants accumulation. This paper aims at comparing the radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa Forel in two different culture media (Pagnocca B and MEA LP). Although total MEA LP radial growth was greater all along the bioassay, no significant difference was detected between growth efficiencies of the two media. Previous evidences of low growth rate for this fungus were confirmed. Since these data cannot point greater efficiency of one culture medium over the other, MEA LP medium is indicated for in vitro studies with this mutualistic fungus due its simpler composition and translucent color, making the analysis easier.