Degradation of Caffeine by Heterogeneous Photocatalysis Using ZnO with Fe and Ag

Abstract The organic compound caffeine when detected in environmental matrices such as surface waters and groundwater is considered as an emerging contaminant, in which its effects are still unknown. Therefore, in the present research, zinc oxide-based catalysts impregnated with iron and silver were prepared for the reaction of caffeine degradation by heterogeneous photocatalysis. The wet impregnation method with excess solvent was applied to the preparation of the materials, later they were characterized by adsorption of N2, X-ray diffraction and photoacoustic spectroscopy. Then, the photodegradation, photolysis and adsorption tests were carried out, in which it was observed that only the presence of the radiation or photocatalysts could not sufficiently degrade the caffeine, however when combined radiation with all the catalysts studied here presented degradation above 70% at the end of 300 minutes of the reaction, and the best catalyst studied was that containing 8% Ag in non-calcined ZnO. Thus, these results point out that the methodology employed in this research, both for the preparation of the catalysts and in the process of the photocatalysis reaction, was efficient in the degradation of the emerging contaminant, caffeine, which could later be used for a mixture of other contaminants.

Inhibitory effect of reduced graphene oxide-silver nanocomposite on progression of artificial enamel caries

Abstract The use of antimicrobial agents is an efficient method to prevent dental caries. Also, nanometric antibacterial agents with wide antibacterial spectrum and strong antibacterial effects can be applied for prevention of dental caries. Objectives: The aim of this study was to evaluate the inhibitory effect of reduced graphene oxide-silver nanoparticles (rGO/Ag) composite on the progression of artificial enamel caries in a Streptococcus mutans biofilm model. Material and Methods: Enamel specimens from bovine incisors were divided into eight treatment groups (n = 13), as follows: group 1 was inoculated with S. mutans grown in Brain Heart Infusion containing 1% sucrose (1% BHIS), as negative control; groups 2-4 were inoculated with S. mutans grown in the presence of different rGO/Ag concentrations (0.08, 0.12, 0.16 mg/mL) + 1% BHIS; group 5-7 were inoculated with S. mutans grown in the presence of different agents (0.16 mg/mL reduced graphene oxide, 0.16 mg/mL silver nanoparticles, 10 ppm NaF) + 1% BHIS; group 8 was mixed with 1% BHIS, without inoculation. Artificial enamel carious lesions were produced by S. mutans biofilm model for 7 days. Confocal laser scanning microscopy and atomic force microscopy were used to analyze roughness and morphology of the enamel surface. Polarized light microscopy and confocal laser scanning microscopy were employed to measure the lesion depth and the relative optical density (ROD) of the demineralized layer. Results: Compared with the control groups, the rGO/Ag groups showed: (a) reduced enamel surface roughness; (b) much smoother and less eroded surfaces; (c) shallower lesion depth and less mineral loss. Conclusion: As a novel composite material, rGO/Ag can be a promising antibacterial agent for caries prevention.

In Vitro Evaluation of the Remineralizing Potential and Antimicrobial Activity of a Cariostatic Agent with Silver Nanoparticles

Abstract Cariostatic treatment has been shown to successfully arrest caries. However, it blackens the carious tooth structure. This study evaluated the effects of an experimental cariostatic agent with silver nanoparticles (Ag-Nano) using microhardness (MH) and microbiological tests. The cariostatic agents tested were: Saforide®, Cariestop®, Ancarie® and Ag-Nano. Sixty-six samples from deciduous enamel were submitted to initial (after pH cycling to obtain initial caries-like lesion) and final (after cariostatic application) MH testing and %MH values were calculated. After longitudinal sectioning, internal (I) MH was evaluated. Strains of Streptococcus mutans, Escherichia coli, and Enterococcus faecalis in brain-heart infusion culture were treated with the cariostatic agents. Agar diffusion tests (ADTs) were performed and minimum inhibitory concentrations were determined. The statistical tests used were: Kruskal-Wallis and Dunn (%MD; ADT; MIC) and ANOVA followed by Tukey's test (I-MH) (p<0.05). The %MH of Saforide® was significantly greater than that of Ag-Nano (p<0.05). Internal MH showed progressive improvement in the enamel remineralization for all cariostatic tested. In ADTs showed greater inhibition of S. mutans, E. faecalis, and E. coli by Saforide® than by Ancarie® and Ag-Nano. Ag-Nano was able to inhibit 100% microorganism growth at a lower concentration than required for the other agents. It was concluded that Ag-Nano treatment promoted remineralization of deciduous tooth enamel with initial caries-like lesion and bactericidal activity.

Resumo O tratamento com cariostático tem demostrado sucesso na paralização da cárie. No entanto, causa escurecimento da estrutura dental cariada. Este estudo avaliou os efeitos de um agente cariostático experimental com nanopartículas de prata (Ag-Nano) através de microdureza (MD) e testes microbiológicos. Os cariostáticos testados foram: Saforide®, Cariestop®, Ancarie® e Ag-Nano. Sessenta e seis amostras de esmalte decíduo foram submetidos a MD inicial (após ciclagem de pH para obtenção da lesão de cárie inicial) e final (após aplicação dos cariostáticos), e os valores da porcentagem (%) de MD foram calculados. Após secção longitudinal, a MD interna (I) foi avaliada. Cepas de Streptococcus mutans, Escherichia coli e E. faecalis foram cultivados em ágar infusão de cérebro e coração (BHI) e submetidos aos cariostáticos testados. Além disso, foram realizados teste de difusão em ágar (TDA) e avaliação da concentração mínima inibitória (CIM) dos cariostáticos. Os testes estatísticos usados foram: Kruskall-Wallis e Dunn (%MD; TDA; CIM) e ANOVA seguido de teste de Tukey (MD-I) (p<0.05). A %MD do Saforide® foi significativamente maior do que a de Ag-Nano (p<0,05). A MD interna apresentou melhora progressiva na remineralização do esmalte para todos os cariostático testados. Os resultados do TDA mostraram que S. mutans, E. faecalis e E. coli sofreram maior inibição pelo Saforide® (p<0,05), em relação ao Ancarie® e Ag-Nano. No entanto, para o teste de CIM o Ag-Nano foi capaz de inibir 100% dos microorganismos, em menor concentração do que os demais cariostaticos. Conclui-se que, o tratamento Ag-Nano foi capaz de promover remineralização do esmalte dental decíduo com lesão de cárie inicial e apresentou atividade bactericida.

AgNPs: The New Allies Against S. Mutans Biofilm - A Pilot Clinical Trial and Microbiological Assay

Abstract: The purpose of this study was to evaluate the antimicrobial properties of a new formulation containing silver nanoparticles, named Nano Silver Fluoride (NSF), to inhibit Streptococcus mutans biofilm formation on children's dental enamel. The variations in dental biofilm pH and in the Simplified-Oral-Hygiene-Index (OHI-S) also were evaluated after the treatment with NSF. This was a randomized, double-blind, crossover and prospective pilot clinical trial study in which 12 schoolchildren, aged between 7-8 years, had their dental enamel treated with two solutions: S1 - Nano Silver Fluoride and S2 - negative control (saline solution), in different experimental moments. The dental biofilm adhered to enamel treated with NSF had lower values of S. mutans viability (absorbance) and colony forming units (CFU) than the S0 (baseline) and S2. There was a statistically significant difference between the OHI-S mean values of S0 and S1. There were no differences between the biofilm pH (both before and after the use of the test substances) and among the different groups. These properties suggest that NSF has bactericidal effect against S. mutans biofilm and it may be used for clinical control and prevention of dental biofilm formation.

Resumo O objetivo do presente estudo foi avaliar as propriedades antimicrobianas de uma nova formulação composta por nanopartículas de prata, denominada nano silver fluoride (NSF), na inibição de biofilme de Streptococcus mutans sobre a superfície do esmalte dentário de crianças. Variações no pH do biofilme dental e nos valores do índice de Higiene Oral Simplificada (IHO-S) também foram avaliadas após o tratamento com NSF. Trata-se de um estudo piloto, randomizado, duplo cego, cruzado e prospectivo. A amostra foi composta por 12 crianças, de ambos os gêneros, com idades entre 7 e 8 anos, as quais utilizaram as duas soluções testes, S1- NSF e S2- controle negativo (solução salina). O biofilme dental tratado com NSF apresentou menores valores de viabilidade de S. mutans (absorbância) e de unidades formadoras de colônias (UFC) do que o biofilme baseline e o biofilme tratado com S2. Houve diferença estatisticamente significativa entre os valores médios de IHO-S dos grupos baseline e S1, com uma redução dos valores. Não houve qualquer variação nos valores de pH do biofilme dental, antes e depois do tratamento com S1 e S2 e entre os diferentes grupos. Estas propriedades sugerem que NSF possui efeito bactericida sobre o biofilme de S. mutans, podendo ser utilizado clinicamente para o controle e prevenção da formação do biofilme dentário.

The effect of silver nanoparticles on composite shear bond strength to dentin with different adhesion protocols

Abstract In Dentistry, restorative materials and oral bacteria are believed to be responsible for restoration failure. To make long-lasting restorations, antibacterial agents should be made. Inorganic nanoparticles and their nano composites are applied as good antibacterial agents. Objective The purpose of this study was to investigate the effect of silver nanoparticles on composite shear bond strength using one etch and rinse and one self-etch adhesive systems. Material and Methods Silver nanoparticles were prepared. Transmission electron microscope and X-ray diffraction were used to characterize the structure of the particles. Nanoparticles were applied on exposed dentin and then different adhesives and composites were applied. All samples were tested by universal testing machine and shear bond strength was assesed. Results Particles with average diameter of about 20 nm and spherical shape were found. Moreover, it was shown that pretreatment by silver nanoparticles enhanced shear bond strength in both etch and rinse, and in self-etch adhesive systems (p≤0.05). Conclusions Considering the positive antibacterial effects of silver nanoparticles, using them is recommended in restorative dentistry. It seems that silver nanoparticles could have positive effects on bond strength of both etch-and-rinse and self-etch adhesive systems. The best results of silver nanoparticles have been achieved with Adper Single Bond and before acid etching.

Silver nanoparticle incorporation effect on mechanical and thermal properties of denture base acrylic resins

ABSTRACT Objective The aim of the present study was to evaluate the mechanical and thermal characteristics of two denture base acrylic resins containing silver nanoparticles (AgNPs). Material and Methods Two different acrylic denture base resins (heat-polymerized and microwave polymerized) containing 0.3, 0.8 and 1.6 wt% AgNPs were evaluated for flexural strength, elastic modulus and impact strength. The glass transition temperature (Tg) and relative heat capacity (Cp) of the samples were determined from the Differential Scanning Calorimetry (DSC) results. For statistical analysis, two-way ANOVA and Tukey-HSD tests were performed. Results Addition of 0.8% and 1.6% AgNPs in microwave-polymerized resin significantly decreased the transverse strength and elastic modulus. In terms of impact strength, the addition of AgNPs has no effect on both resin groups. Glass transition temperature (Tg) was decreased with the addition of AgNPs for both denture base resins. Conclusions The incorporation of AgNPs, generally used for antimicrobial efficiency, affected the transverse strength of the denture base acrylic resins depending on the concentration of nanoparticles. Tg was decreased with the addition of AgNPs for both denture base resins.

Effect of Silver Nanoparticles on Physicochemical and Antibacterial Properties of Calcium Silicate Cements

Abstract Mineral trioxide aggregate (MTA) and Portland cement (PC) are calcium silicate cements. They have similar physicochemical, mechanical and biological properties. The addition of zirconium oxide (ZrO2) to PC provides radiopacity. Silver nanoparticles (AgNPs) may improve some properties of cements. The aim of this study was to evaluate the effect of AgNPs on physicochemical/mechanical properties and antibacterial activity of white MTA (WMTA) and PC associated with ZrO2. The following materials were evaluated: WMTA; PC 70% + ZrO2 30%; WMTA+ AgNPs; and PC 70% + ZrO2 30% + AgNPs. The study evaluated radiopacity, setting time, pH, compressive strength and solubility. For radiopacity analysis, radiographs were made alongside an aluminum (Al) step wedge. To evaluate the antibacterial activity, direct contact test was performed on planktonic cells and Enterococcus faecalis biofilm induced on bovine root dentin for 14 days. The experimental periods were 5 and 15 h. Data were obtained as CFU mL-1. The obtained data were submitted to ANOVA and Tukey tests (p<0.05). The addition of AgNPs to WMTA increased the pH, lowered the solubility and the initial and final setting times. The addition of AgNPs to PC/ZrO2 maintained the pH, lowered the solubility, and increased the setting time and compressive strength. The radiopacity of all materials was higher than 4 mmAl. The addition of AgNPs promoted an increase in antibacterial activity for calcium silicate cements and favored the physicochemical and mechanical properties of the materials.

Resumo Mineral trióxido agregado (MTA) e cimento Portland (CP) são cimentos à base de silicato de cálcio. Eles apresentam propriedades físico-químicas, mecânica e biológicas semelhantes. A adição de óxido de zircônio (ZrO2) ao CP confere radiopacidade. Nanopartículas de prata (NPsAg) podem melhorar propriedades dos cimentos. O objetivo deste estudo foi avaliar o efeito da NPsAg nas propriedades físico-químicas, mecânicas e na atividade antibacteriana do MTA branco (WMTA) e CP associado ao ZrO2. Os seguintes materiais foram avaliados: WMTA; CP 70% + ZrO2 30%; ; WMTA + NPsAg; CP 70% + ZrO2 30% + NPsAg. Foram avaliados a radiopacidade, tempo de presa, pH, resistência à compressão e solubilidade. Para análise da radiopacidade foram tiradas radiografias ao lado de uma escala de alumínio (Al). Para avaliar a atividade antibacteriana, foi realizado o teste de contato direto sobre células planctônicas e biofilme de Enterococcus faecalis formado em dentina radicular bovina durante 14 dias. Os períodos experimentais foram 5 e 15 h. Os dados foram obtidos como UFC mL-1 e submetidos aos testes de ANOVA e Tukey (p<0,05). A adição de NPsAg ao WMTA elevou o pH, diminuiu a solubilidade e os tempos de presa inicial e final. A adição de NPsAg ao CP/ZrO2 manteve o pH, diminuiu a solubilidade, aumentou o tempo de presa e a resistência à compressão. A radiopacidade de todos os materiais foi maior do que 4 mmAl. A adição de NPsAg promoveu um aumento da atividade antibacteriana dos cimentos à base de silicato de cálcio e favoreceu as propriedades físico-químicas e mecânicas dos materiais.

Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive

ABSTRACT Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (p<0.001) and DC in situ (p<0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p<0.05). Conclusions The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive.

Effect of cantilever length and alloy framework on the stress distribution in peri-implant area of cantilevered implant-supported fixed partial dentures

ABSTRACT Because many mechanical variables are present in the oral cavity, the proper load transfer between the prosthesis and the bone is important for treatment planning and for the longevity of the implant-supported fixed partial denture. Objectives To verify the stress generated on the peri-implant area of cantilevered implant-supported fixed partial dentures and the potential effects of such variable. Material and Methods A U-shaped polyurethane model simulating the mandibular bone containing two implants (Ø 3.75 mm) was used. Six groups were formed according to the alloy’s framework (CoCr or PdAg) and the point of load application (5 mm, 10 mm and 15 mm of cantilever arm). A 300 N load was applied in pre-determined reference points. The tension generated on the mesial, lingual, distal and buccal sides of the peri-implant regions was assessed using strain gauges. Results Two-way ANOVA and Tukey statistical tests were applied showing significant differences (p<0.05) between the groups. Pearson correlation test (p<0.05) was applied showing positive correlations between the increase of the cantilever arm and the deformation of the peri-implant area. Conclusions This report demonstrated the CoCr alloy shows larger compression values compared to the PdAg alloy for the same distances of cantilever. The point of load application influences the deformation on the peri-implant area, increasing in accordance with the increase of the lever arm.

Dissolution of a mineral trioxide aggregate sealer in endodontic solvents compared to conventional sealers

Abstract The aim of this study is to evaluate the solubility of a Mineral Trioxide Aggregate sealer (MTA-Fillapex) compared with five other sealers, calcium hydroxide (Sealapex), resin (Realseal), zinc oxide-eugenol (Tubli-Seal), and two epoxy resins (AH-26 and AH-Plus), in chloroform and eucalyptoil in static and ultrasonic environments. Samples of each sealer were prepared (n = 180) and then divided into 12 groups that were immersed in solvents for 5 and 10 min in static and ultrasonic environments. The mean weight loss was determined, and the values were compared using Student's t-test, One-way ANOVA, and Tukey's HSD post-hoc test (p < 0.05). In chloroform, MTA-Fillapex, AH-26, and Sealapex displayed moderate solubility with no significant difference in dissolution (p = 0.125); however, their dissolution was significantly lower than that of AH-Plus (p < 0.001), which was almost fully dissolved after 10 minutes. Realseal was significantly less soluble than all sealers (p < 0.001). In eucalyptoil, MTA-Fillapex showed low solubility, as all of the sealers did, but Tubli-Seal was significantly more soluble than other sealers (p < 0.001). Using ultrasonic activation resulted in a significantly higher dissolution rate in chloroform for all sealers except MTA-Fillapex after 10 min (p = 0.226). In eucalyptoil, ultrasonic activation significantly increased the dissolution rate of all sealers except MTA-Fillapex after 5 and 10 min, Sealapex at 10 min, and AH-Plus at 5 min (p > 0.05). In conclusion, MTA-Fillapex was not sufficiently dissolved in either solvent. Ultrasonic activation had limited effectiveness on MTA-Fillapex dissolution, whereas it significantly increased the efficiency of solvents in dissolving a number of endodontic sealers.

In vitro antibacterial activity of a silicone-based endodontic sealer and two conventional sealers

Abstract The aim of this study was to evaluate whether the modification in the silver component is capable of providing GuttaFlow 2 with antibacterial activity against Enterococcus faecalis compared with epoxy resin-based (AH Plus) and zinc oxide and eugenol-based (Endofill) sealers. The antibacterial activity was evaluated using a reference strain of E. faecalis (ATCC 29212). Freshly mixed sealers were subjected to the agar diffusion test (ADT), while the direct contact test (DCT) was performed after materials setting. ADT results were obtained through measurements, in millimeters, of the inhibition zones promoted by the materials, using a digital caliper. In DCT, values of CFU/mL promoted by the three sealers were compared in three experimental periods (1 min, 1 h, and 24 h). The data were analyzed using Kruskal-Wallis and Dunn post-hoc tests (p < 0.05). In both ADT and DCT, GuttaFlow 2 presented no effect against E. faecalis, while Endofill and AH Plus showed similar inhibition zones. Endofill was the only material capable of reducing bacterial growth in DCT. In conclusion, modifications in the silver particle of GuttaFlow 2 did not result in a sealer with antibacterial effect against E. faecalis.

Pre-heating mitigates composite degradation

ABSTRACT Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey’s tests (α=5%). Results Radiopacity levels were as follows: Durafill VS<Z-350<Z-250 (p<0.05). The depth of silver penetration into the composites ranked as follows: Durafill VS>Z-350>Z-250 (p<0.05). After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05). There was a lower penetration of silver in pre-heated specimens (p<0.05). Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

Use of Silver Nanoparticles Reduces Internal Contamination of External Hexagon Implants by Candida albicans

Abstract: Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface byCandida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.

Resumo: A interface implante/pilar não pode ser totalmente selada para passagem de microrganismos, com isso o interior do implante torna-se um reservatório de microrganismos patogênicos que promovem e mantêm a inflamação crônica nos tecidos em volta dos implantes. Nanopartículas de prata são agentes antimicrobianos potentes e de amplo espectro. O objetivo deste estudo foi avaliar a capacidade das nanopartículas de prata em evitar a contaminação porCandida albicans do interior de implantes, originada da infiltração do fungo através da interface implante/pilar. 36 implantes foram utilizados neste experimento. Três grupos de estudo foram estabelecidos: grupo experimental (os implantes receberam aplicação de nanopartículas de prata na sua cavidade interna, antes da instalação do pilar); grupo controle positivo (os implantes receberam PBS estéril em vez das nanopartículas de prata) e grupo controle negativo (implantes receberam aplicação de nanopartículas de prata na cavidade interna, mas os implantes foram imersos em meio estéril). Nos grupos controle positivo e experimental, os implantes foram imersos em suspensão deCandida albicans. Os pilares protéticos de todos os grupos foram parafusados com torque de 10 N. Após 72 h imersos na suspensão deC. albicans ou em meio estéril, os pilares foram removidos e amostras da superfície interna dos implantes foram coletadas com cone de papel absorvente para a detecção de Candida. No grupo controle negativo não foi observada contaminação por C. albicans. O grupo-controle positivo mostrou valores de unidades formadoras de colônia deCandida estatisticamente maiores quando comparado com o grupo experimental. Conclui-se que nanopartículas de prata reduzem a colonização de C. albicans dentro dos implantes, mesmo quando o pilar é parafusado com torque baixo.

Completeness of tuberculosis reporting forms for disease control in individuals with HIV/AIDS in priority cities of Bahia state / Completude das fichas de notificação de Tuberculose nos municípios prioritários da Bahia para controle da doença em indivíduos com HIV/AIDS

The control of HIV / Tuberculosis (TB) co -infection remains a challenge for public health. Notification is mandatory for both diseases and the National Case Registry Database (Sinan) is responsible for the collection and processing of individual forms of reporting and monitoring. The adequate fulfillment of these fields chips (completeness) is essential to follow the dynamics of the disease and set priorities for intervention. The aim of this study was to evaluate the completeness of the notification forms of tuberculosis in the priority municipalities of Bahia (Camaçari , Feira de Santana , Ilhéus , Itabuna, Jequié, Lauro de Freitas , Porto Seguro , Teixeira de Freitas , Paulo Afonso, Barreiras and Salvador) to control the disease in individuals with HIV/AIDS using tabulations obtained from the Sinan in the period from 2001 to 2010. The results showed that despite the completeness of the field HIV be above 50 %, more than half the cases were met as "undone" or "being processed" in all municipalities assessed in the period. The low completeness of reporting forms may compromise the quality of surveillance of TB cases. The results suggest the need for greater availability of HIV testing in these individuals.

O controle da coinfecção HIV/Tuberculose (TB) ainda representa um desafio para a saúde pública. Ambas as doenças são de notificação obrigatória e o Sistema Nacional de Agravos de Notificação (SINAN) é o órgão responsável pela coleta e processamento das fichas individuais de notificação e acompanhamento. O preenchimento adequado dos campos destas fichas (completude) é essencial para acompanhar a dinâmica da doença e definir prioridades de intervenção. O objetivo deste estudo foi avaliar a completude das fichas de notificações de tuberculose nos municípios prioritários da Bahia (Camaçari, Feira de Santana, Ilhéus, Itabuna, Jequié, Lauro de Freitas, Porto Seguro, Teixeira de Freitas, Paulo Afonso, Barreiras e Salvador), para controle da doença em indivíduos com HIV/AIDS, através dos relatórios de tabulação do Sinan, no período de 2001 a 2010. Os resultados demonstraram que, apesar da completude do campo HIV estar acima de 50%, mais da metade das fichas estavam preenchidas como "não realizado" ou "em andamento", em todos os municípios avaliados no período. A baixa completude das fichas de notificação pode comprometer a qualidade de vigilância dos casos de TB. Os resultados sugerem a necessidade de maior disponibilidade de teste para HIV nesses indivíduos.

Development of a novel resin with antimicrobial properties for dental application

The adhesion of biofilm on dental prostheses is a prerequisite for the occurrence of oral diseases. Objective: To assess the antimicrobial activity and the mechanical properties of an acrylic resin embedded with nanostructured silver vanadate (β-AgVO3). Material and Methods: The minimum inhibitory concentration (MIC) of β-AgVO3 was studied in relation to the species Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC 25175, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231. The halo zone of inhibition method was performed in triplicate to determine the inhibitory effect of the modified self-curing acrylic resin Dencor Lay - Clássico®. The surface hardness and compressive strength were examined. The specimens were prepared according to the percentage of β-AgVO3 (0%-control, 0.5%, 1%, 2.5%, 5%, and 10%), with a sample size of 9x2 mm for surface hardness and antimicrobial activity tests, and 8x4 mm for the compression test. The values of the microbiologic analysis were compared and evaluated using the Kruskal-Wallis test (α=0.05); the mechanical analysis used the Shapiro-Wilk's tests, Levene's test, ANOVA (one-way), and Tukey's test (α=0.05). Results: The addition of 10% β-AgVO3 promoted antimicrobial activity against all strains. The antimicrobial effect was observed at a minimum concentration of 1% for P. aeruginosa, 2.5% for S. aureus, 5% for C. albicans, and 10% for S. mutans. Surface hardness and compressive strength increased significantly with the addition of 0.5% β-AgVO3 (p<0.05). Higher rates of the nanomaterial did not alter the mechanical properties of the resin in comparison with the control group (p>0.05). Conclusions: The incorporation of β-AgVO3 has the potential to promote antimicrobial activity in the acrylic resin. At reduced rates, it improves the mechanical properties, and, at higher rates, it does not promote changes in the control. .

Effect of veneering material on the deformation suffered by implant-supported fixed prosthesis framework

Knowing how stresses are dissipated on the fixed implant-supported complex allows adequate treatment planning and better choice of the materials used for prosthesis fabrication. Objectives: The aim of this study was to evaluate the deformation suffered by cantilevered implant-supported fixed prostheses frameworks cast in silver-palladium alloy and coated with two occlusal veneering materials: acrylic resin or porcelain. Material and Methods: Two strain gauges were bonded to the inferior surface of the silver-palladium framework and two other were bonded to the occlusal surface of the prosthesis framework covered with ceramic and acrylic resin on each of its two halves. The framework was fixed to a metallic master model and a 35.2 N compression force was applied to the cantilever at 10, 15 and 20 mm from the most distal implant. The measurements of deformation by compression and tension were obtained. The statistical 2-way ANOVA test was used for individual analysis of the experiment variables and the Tukey test was used for the interrelation between all the variables (material and distance of force application). Results: The results showed that both variables had influence on the studied factors (deformation by compression and tension). Conclusion: The ceramic coating provided greater rigidity to the assembly and therefore less distortion compared with the uncoated framework and with the resin-coated framework. The cantilever arm length also influenced the prosthesis rigidity, causing higher deformation the farther the load was applied from the last implant. .

Synthesis of silver nanoparticles using a biosurfactant produced in low-cost medium as stabilizing agent

Background A biosurfactant produced by Pseudomonas aeruginosa cultivated in a low-cost medium formulated with 2.5% vegetable oil refinery residue and 2.5% corn steep liquor and distilled water was employed to stabilize silver nanoparticles in the liquid phase. The particles were initially synthesized using NaBH4 as reducing agent in biosurfactant reverse micelles and were extracted from the micellar solution to disperse in heptane. Results A silver particle size in the range of 1.13 nm was observed. The UV-vis absorption spectra proposed that silver nanoparticles could be formed in the reverse micelles and relatively stabilized for at least 3 months without passivator addition. The Transmission Electron Microscope (TEM) shows that the silver nanoparticles are of spherical form and relatively uniform. Conclusions This process provided a simpler route for nanoparticle synthesis compared to existing systems using whole organisms or partially purified biological extracts, showing that the low-cost biosurfactant can be used for nanoparticle synthesis as a non-toxic and biodegradable stabilizing agent.

Biosynthesis of silver nanoparticles using fresh extracts of Tridax procumbens Linn.

A simple and eco-friendly method for the synthesis of biogenic nanoparticles (NP’s) using an aqueous solution of T. procumbens fresh plant extract (leaf and stem) as a bioreductant is reported. The prepared biogenic nanoparticles were well characterized using U.V. visible spectroscopy, scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. The particles were confirmed to be elemental crystal by X-ray diffraction. The potential applications of biosynthesized nanoparticles as antimicrobial (antibacterial and antifungal) against pathogens Escherichia coli, Vibrio cholerae, Aspergillus niger and Aspergillus flavus were demonstrated.

Addition of Silver Nanoparticles to Composite Resin: Effect on Physical and Bactericidal Properties In Vitro

The objectives of this study were to evaluate physical properties and antibacterial activity of a light-activated composite modified with silver nanoparticles. Discs were produced with unmodified resin (control group - CG) and modified resin with silver nanoparticles at two concentrations, 0.3% wt (MR03) and 0.6% wt (MR06). Streptococcus mutans and Lactobacillus acidophilus biofilms were induced in vitro by incubation of discs in a 20% sucrose medium, followed by sonication and counting of viable cells after 1, 4 and 7 days (n=9). The arithmetic roughness of all three groups was evaluated by atomic force microscopy (n=9). Compression assay was conducted in all groups to measure the compressive strength at failure and elasticity modulus (n=5). Data were subjected to ANOVA and Tukey's tests (α=0.05%). At all three time points the number of viable cells was statistically lower for MR03 and MR06 compared with CG, for both specimens. MR03 and MR06 showed no significant differences. Microscopic analysis demonstrated no significant differences for roughness among the three groups (p>0.05). The MR03 was stronger to compression than CG, and MR06 was statistically lower than CG and MR03. It was concluded that the MR03 were less conducive to biofilm growth, without compromising the strength in compression and surface roughness.

Os objetivos do estudo foram avaliar as propriedades físicas e a atividade antibacteriana de uma resina composta fotopolimerizável modificada com nanopartículas de prata. Discos foram produzidos com resina não modificada (grupo controle - GC) e resina modificada com nanopartículas de prata em duas concentrações 0,3 e 0,6% em massa (MR03 e MR06, respectivamente). Biofilmes de Streptococcus mutans e Lactobacillus acidophilus foram induzidos in vitro pela incubação dos discos em meio líquido com 20% de sacarose, seguida pela sonicação e contagem de células viáveis após 1, 4 e 7 dias. A rugosidade aritmética de todos os grupos foi avaliada por microscopia de força atômica (MFA). Os dados foram submetidos à ANOVA e ao Teste de Tukey (α=0,05%). Nos três períodos de tempo, o número de células viáveis foi estatisticamente mais baixo para MR03 e MR06, em comparação com GC, para ambas as espécies. MR03 e MR06 não apresentaram diferenças significantes. A análise por meio de MFA demonstrou que não houve diferença significante para a rugosidade entre os três grupos. MR03 apresentouse mais resistente em compressão do que GC, e o desempenho em compressão em MR06 foi estatisticamente pior do que em GC e MR03. Foi possível concluír que as resinas modificadas de MR03 inibiram o crescimento dos biofilmes, sem comprometimento da resistência à compressão e da rugosidade superficial.

Development of Intracanal Formulation Containing Silver Nanoparticles

This study aimed to synthetize, characterize and evaluate the antimicrobial properties of silver nanoparticles to be used in the development of a root intracanal formulation. Silver nanoparticles (AgNPs) were obtained by reduction of silver nitrate with sodium borohydride and characterized by UV-Visible spectrophotometry, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antimicrobial activity of nanoparticle formulation was evaluated by determinations of the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against different bacterial species by the microdilution method, according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Three potential vehicles, hydroxyethylcellulose, Carbomer and polyethylene glycol were tested as carriers for formulations containing AgNPs. The efficiency of the synthesis method chosen to produce AgNPs was demonstrated by four characterization techniques. The nanoparticles showed antibacterial activity against all species tested. Incorporation of AgNPs into all experimental vehicles produced stable formulations but the one in hydroxyethylcellulose presented better physical proprieties. The results indicate that silver nanoparticles are potential antiseptic agents to be used in root canals and incorporation in adequate vehicles may favor a broader application.

O presente estudo teve como objetivo sintetizar, caracterizar e avaliar as propriedades antimicrobianas de nanopartículas de prata visando o desenvolvimento de uma formulação intracanal. As nanopartículas de prata (AGNPS) foram obtidas pela redução de nitrato de prata com borohidreto de sódio e caracterizados por espectrofotometria UV-Visível, microscopia eletrônica de varredura (MEV) e espalhamento de dinâmico de luz (DLS). A atividade antimicrobiana da formulação de nanopartículas foi avaliada por meio das determinações da concentração inibitória mínima (CIM) e a concentração bactericida mínima (CBM) contra diferentes espécies de bactérias pelo método de microdiluição, de acordo com recomendações do Clinical and Laboratory standards Institute (CLSI). Três potenciais veículos, hidroxietilcelulose, carbómero e polietileno glicol foram testados como veículos para as formulações de AGNPS. A eficiência do método de síntese escolhido para produzir AGNPS foi demonstrada por quatro técnicas de caracterização. As nanopartículas apresentaram atividade antibacteriana contra todas as espécies bacterianas testadas. A incorporação de AGNPS em todos os veículos experimentais produziram formulações estáveis, porém, quando utilizado a hidroxietilcelulose foram obtidos melhores propriedades físicas. Os resultados indicam que as nanopartículas de prata são potenciais agentes anti-sépticos para serem usados na terapia endodôntica e a incorporação em veículos adequados pode favorecer uma aplicação mais ampla.