Antimicrobial and mechanical properties of acrylic resins with incorporated silver-zinc zeolite - part I

Objective: The purpose of this in vitro study was to evaluate the antimicrobial activity of acrylic resins containing different percentages of silver and zinc zeolite, and to assess whether the addition of zeolite alters the flexural and impact strength of the resins. Background: The characteristics of acrylic resins support microorganism development that can threaten the health of the dentures user. Material and methods: A microwave-polymerised (Onda-Cryl) and two heat-polymerised (QC20 and Lucitone 550) acrylic resins were used. The materials were handled according to the manufacturers` instructions. Fifty rectangular-shaped specimens (8 x 10 x 4mm) were fabricated from each resin and assigned to 5 groups (n = 10) according to their percentage of Irgaguard B5000 silver-zinc zeolite (0%- control, 2.5%, 5.0%, 7.5% and 10%). Flexural strength and Izod impact strength were evaluated. The antimicrobial activity against two strains of Candida albicans and two strains of Streptococcus mutans was assessed by agar diffusion method. Data were analysed statistically by one-way ANOVA and Tukey`s test at 5% significance level. Results: The addition of 2.5% of Irgaguard B5000 to the materials resulted in antimicrobial activity against all strains. Flexural strength decreased significantly with the addition of 2.5% (QC20 and Lucitone 550) and 5.0% (Onda-Cryl) of Irgaguard B5000. The impact strength decreased significantly with the addition of 2.5% (Lucitone 550) and 5.0% (QC20 and Onda-Cryl) of zeolite. Conclusion: The addition of silver-zinc zeolite to acrylic resins yields antimicrobial activity, but may affect negatively the mechanical properties, depending on the percentage of zeolite.

Use of the checkerboard DNA-DNA hybridisation technique for in vivo detection of cariogenic microorganisms on metallic brackets, with or without use of an antimicrobial agent

Objective: Using checkerboard DNA-DNA hybridisation (CDDH) assay, this randomised clinical study evaluated the contamination of metallic brackets by four cariogenic bacterial strains (Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei and Lactobacillus acidophilus) and the efficacy of 0.12% chlorhexidine gluconate (CHX) mouthwashes in reducing bacterial contamination. Methods: Thirty-nine 11-33-year-old patients under treatment with fixed orthodontic appliances were enrolled in the study and had 2 new metallic brackets bonded to premolars. Nineteen patients used a 0.12% CHX mouthwash (Periogard (R)) and 20 patients used a placebo mouthwash (control) twice a week. After 30 days, the brackets were removed and samples were obtained for analysis by CDDH. Data were analysed statistically by the Kruskal-Wallis test (alpha = 0.05) using the SAS software. Results: S. mutans, S. sobrinus, L. casei and L. acidophilus were detected in 100% of the samples from both groups. However, brackets of the control group were more heavily contaminated by S. mutans and S. sobrinus (P < 0.01). In the experimental group, although all counts decreased after rinsing with the chlorhexidine solution, there was significant difference only for S. mutans (P = 0.03). Conclusions: The use of 0.12% chlorhexidine gluconate mouthwashes can be useful in clinical practice to reduce the levels of cariogenic microorganisms in patients under treatment with fixed orthodontic appliances. (C) 2011 Elsevier Ltd. All rights reserved.

Efficacy of Microwaves and Chlorhexidine on the Disinfection of Pacifiers and Toothbrushes: An In Vitro Study

Purpose: The purpose of this study was to evaluate, in vitro, the contamination of toothbrushes and pacifiers by Streptococcus mutans, and the efficacy of microwave and chlorhexidine for their disinfection. Methods: Sixty pacifiers and 60 toothbrushes were contaminated with S mutans and then divided into groups according to the disinfection protocol: Group 1-chlorhexidine solution; Group 2-microwave sterilization; and Group 3-sterile tap water. The devices were evaluated microbiologically as to the formation of S mutans colonies/biofilms and were examined by scanning electron microscopy. The results were submitted for statistical analysis by Friedman`s test at a 5% significance level. Results: The results of both types of evaluation showed a large number of S mutans colonies/biofilms after spraying with sterile tap water, and chlorhexidine spraying and microwaving were effective in eliminate colonies/biofilms. Groups 1 and 2 were statistically similar to each other (P>.05) and differed significantly from Group 3 (P<.05). Conclusions: The 0.12% chlorhexidine solution spray and 7 minutes of microwave irradiation were effective for disinfection of pacifiers and toothbrushes. (Pediatr Dent 2011;33:10-3) Received July 29, 2009 I Last Revision January 26, 2010 I Accepted March 10, 2010

Effect of Three Methods for Cleaning Dentures on Biofilms Formed In Vitro on Acrylic Resin

Purpose: The aim of this study was to evaluate the effect of three denture hygiene methods against different microbial biofilms formed on acrylic resin specimens. Materials and methods: The set (sterile stainless steel basket and specimens) was contaminated (37 degrees C for 48 hours) by a microbial inoculum with 106 colony-forming units (CFU)/ml (standard strains: Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Candida albicans, Pseudomonas aeruginosa, and Enterococcus faecalis; field strains: S. mutans, C. albicans, C. glabrata, and C. tropicalis). After inoculation, specimens were cleansed by the following methods: (1) chemical: immersion in an alkaline peroxide solution (Bonyplus tablets) for 5 minutes; (2) mechanical: brushing with a dentifrice for removable prostheses (Dentu Creme) for 20 seconds; and (3) a combination of chemical and mechanical methods. Specimens were applied onto a Petri plate with appropriate culture medium for 10 minutes. Afterward, the specimens were removed and the plates incubated at 37 degrees C for 48 hours. Results: Chemical, mechanical, and combination methods showed no significant difference in the reduction of CFU for S. aureus, S. mutans (ATCC and field strain), and P. aeruginosa. Mechanical and combination methods were similar and more effective than the chemical method for E. faecalis, C. albicans (ATCC and field strain), and C. glabrata. The combination method was better than the chemical method for E. coli and C. tropicalis, and the mechanical method showed intermediate results. Conclusion: The three denture hygiene methods showed different effects depending on the type of microbial biofilms formed on acrylic base resin specimens.

A new type of Brazilian propolis: Prenylated benzophenones in propolis from Amazon and effects against cariogenic bacteria

Ethanol extracts of four propolis samples (E1-E4) from Manaus (Brazilian Amazon) were analysed by HPLC/DAD/ESI-MS/MS and GC/EIMS. The major constituents of E2 and E4 were analysed by NMR ((1)H and (13)C) and ESI/MS/MS. The main constituents of E2 and E4 are polyprenylated benzophenones: 7-epi-nemorosone, 7-epi-clusianone (major E4 constituents), xanthochymol and gambogenone (major E2 constituents), making up a chemical profile so far unreported for Brazilian propolis. Aristhophenone, methyl insigninone, 18-ethyloxy-17-hydroxy-17,18-dihydroscrobiculatone B, and derivatives of dimethyl weddellianone A and B, propolones, and a scrobiculatone derivative, were detected as minor constituents. Triterpenoids (beta-amyrins, beta-amyrenone, lupeol and lupenone) were ubiquitous and predominant in El and E3. The extracts E2 and E4 were highly active against the cariogenic bacteria Streptococcus mitis, Streptococcus mutans and Streptococcus salivarius. E2 was more active than E4, probably due to a higher content of 2-epi-nemorosone, while the latter was richer in di-hydroxylated compounds. (C) 2010 Elsevier Ltd. All rights reserved.

Some factors associated with dental caries in the primary dentition of children with Down syndrome

Aim It is well reported in the scientific literature that there is a high level of periodontal disease and lower caries prevalence in Down Syndrome (DS) individuals, when compared with age-matched non DS individuals. This study was conducted to investigate the process of dental caries in DS children. Materials and methods In this study the following parameters were considered: oral hygiene habits, levels of Streptococcus mutans (SM) and Lactobacillus spp. (LB), Modified Gingival Index (MGI), and Simplified Oral Hygiene Index (OHI-S). A case group with DS children (n=69) and a control group of non DS children (n=69) were formed to perform this study Dental caries severity was determined using the DMFT index. Samples of non-stimulated saliva were collected to determine the Lactobacillus spp levels. For SM levels, MSB agar plates were used. Results The findings revealed that the case group attended, dental check-ups more frequently brushed their teeth more times per day, flossed less, and also more frequently had SM levels classified as ""high count"". The MGI was higher and the OHI-S was lower than the control group (p<0.001). Conclusion No significant differences were found between the DMFT indexes of children from the two groups (p=0.345). The logistic regression analysis showed that in the case group, age, MGI, and SM count were positively related to dental caries (p<0.05).

Determination of dental decay rates with optical coherence tomography

We report the use of optical coherence tomography (OCT) to detect and quantify demineralization process induced by S. mutans biofilm in third molars human teeth. Artificial lesions were induced by a S. mutans microbiological culture and the samples (N = 50) were divided into groups according to the demineralization time: 3, 5, 7, 9, and 11days. The OCT system was implemented using a light source delivering an average power of 96 mu W in the sample arm, and spectral characteristics allowing 23 mu m of axial resolution. The images were produced with lateral scans step of 10 pan and analyzed individually. As a result of the evaluation of theses images, lesion depth was calculated as function of demineralization time. The depth of the lesion in the root dentine increased from 70 pm to 230,urn (corrected by the enamel refraction index, 1.62 @ 856 nm), depending of exposure time. The lesion depth in root dentine was correlated to demineralization time, showing that it follows a geometrical progression like a bacteria growth law. [GRAPHICS] Progression of lesion depth in root dentine as function of exposure time, showing that it follows a geometrical progression like a bacteria growth law(C) 2009 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA

Susceptibility of Staphylococcus aureus to porphyrin-mediated photodynamic antimicrobial chemotherapy: an in vitro study

The ability of Staphylococcus aureus to develop multidrug resistance is well documented, and the antibiotic resistance showed by an increasing number of bacteria has shown the need for alternative therapies to treat infections, photodynamic therapy (PDT) being a potential candidate. The aim of this study was to determine the effect of photodynamic therapy as a light-based bactericidal modality to eliminate Staphylococcus aureus. The study investigated a technique based on a combination of light and a photosensitizer that is capable of producing oxidative species to induce a cytotoxic effect. A Staphylococcus aureus suspension was exposed to a light emitting diode (LED) emitting at 628 nm, 14.6 mW/cm(2), and energy density of 20J/cm(2), 40J/cm(2), or 60 J/cm(2) in the presence of different porphyrin concentrations (PhotogemA (R)). Three drug concentrations were employed: 12 mu l/ml, 25 mu l/ml, and 50 mu l/ml. The treatment response was evaluated by the number of bacterial colony forming units (CFU) after light exposure. The results indicated that exposure to 60 J/cm(2) eliminated 100% (10 log(10) scales) of bacteria, on average. The best PDT response rate to eliminate Staphylococcus aureus was achieved with exposure to LED light in combination with the photosensitizer at concentrations ranging from 25 mu l/ml to 50 mu l/ml. These data suggest that PDT has the potential to eliminate Staphylococcus aureus in suspension and indicates the necessary drug concentration and light fluency.

Avaliação clínica, microbiológica e radiográfica de lesões de cárie de molares decíduos, após remoção parcial da dentina cariada

O objetivo do trabalho foi avaliar as alterações clínicas, microbiológicas e radiográficas de lesões profundas de cárie, após a remoção parcial do tecido cariado e o selamento das cavidades. Vinte pacientes com idade entre quatro e sete anos participaram do estudo, totalizando uma amostra de quarenta e dois dentes com lesões profundas de cárie, distribuída em dezenove cavidades oclusais, doze ocluso-proximais, nove ocluso-linguais e duas ocluso-mésio-distais. O tratamento consistiu na escavação completa do tecido cariado localizado nas paredes laterais e marginais das cavidades, além da remoção superficial da dentina cariada localizada na parede pulpar. Após o término do preparo cavitário, a dentina remanescente foi avaliada quanto à sua coloração e à sua consistência, obtendo-se coletas deste tecido para análise bacteriológica. A seguir, os dentes foram aleatoriamente divididos em dois grupos, de acordo com o material forrador aplicado sobre o tecido cariado (cimento de hidróxido de cálcio ou lâmina de guta-percha), sendo, então, restaurados com resina composta. Imediatamente depois da intervenção clínica, utilizaram-se dispositivos padronizados para a execução da tomada radiográfica inicial. Ao longo do estudo, um dente de cada grupo apresentou necrose pulpar e perdeu-se uma amostra do grupo guta-percha. Após o período experimental, compreendido entre quatro e sete meses, os dentes (n=39) foram novamente radiografados e reabertos para avaliação clínica e para a execução de nova coleta microbiológica. Alterações significativas foram encontradas quanto à coloração e consistência, em que o tecido, inicialmente castanho-claro e amolecido, mostrou-se predominantemente castanho-escuro e endurecido. Em relação à quantidade de unidades formadoras de colônias, observou-se uma redução significativa no número de lactobacilos, estreptococos do grupo mutans e do total de bactérias viáveis em aerobiose e em anaerobiose. Ao exame radiográfico, onde avaliou-se a diferença de densidade radiográfica, através do método de subtração de imagem, não se encontraram alterações significativas. Portanto, estes resultados sugeriram a possibilidade de inativação do processo carioso, através do selamento de lesões profundas de cárie com material adesivo, independente da utilização do cimento de hidróxido de cálcio como material forrador.

Abscesso pulmonar de aspiração : dados diagnósticos e resultados terapêuticos em 241 casos

O abscesso de pulmão continua sendo hoje, em plena era dos antibióticos, um importante problema médico. O presente trabalho se propõe mostrar aspectos diagnósticos e terapêuticos da doença em uma série de pacientes coletada nos últimos 34 anos em um hospital universitário especializado em doenças pulmonares. No período de 1968 a 2002 foram reunidos e estudados 241 casos de abscesso pulmonar de aspiração - 199 em homens e 42 em mulheres, com média de idade de 41,3 anos. Em 69,0% dos pacientes esteve presente a ingestão de álcool e em 64,0% o hábito tabágico. Tosse, expectoração, febre e comprometimento do estado geral foram os achados clínicos mais freqüentes, encontrados na quase totalidade dos casos; 62,5% tinham dor torácica e 30,0% hipocratismo digital. Verificaram-se dentes em mau estado de conservação em 81,7 % dos pacientes, episódio de perda de consciência em 78,0% e presença de odor fétido em 66,0%. Em 85,5% das vezes as lesões localizaram-se em segmento posterior de lobo superior ou segmento superior de lobo inferior, 97,1% delas unilaterais, ocorrendo com igual freqüência tanto no pulmão direito como no esquerdo. A maioria das lesões (66,0%) mediram entre 4,0 e 8,0 cm de diâmetro. Em 25 pacientes (10,4%) houve a associação de empiema pleural. Flora mista, indicativa da presença de germes anaeróbios, foi identificada em secreções broncopulmonares ou pleurais em 172 pacientes (71,4 %). Estreptococos e Gram negativos aeróbios foram também algumas vezes encontrados. Todos os pacientes foram inicialmente tratados com antibióticos (penicilina em 78,0% das vezes) e submetidos a sessões de drenagem postural. Em 51 (21,2%) acabou sendo necessário algum procedimento cirúrgico (24 drenagens de empiema, 21 ressecções pulmonares e 6 pneumostomias). Cura foi obtida em 231 pacientes (95,8%) e 10 (4,2%) foram ao óbito, estes em geral com grandes abscessos, três dos quais também com empiema.

Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis

SIQUEIRA JR. et al. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., v. 104, n. 1, p. 122-130, 2007.

Avaliação in vitro da atividade antimicrobiana de diferentes soluções a base de hidróxido de cálcio

The science of Dentistry wishes obtains the ideal solution for the dental plaque chemical control. This research evaluated antimicrobial action capacity in calcium hydroxide and tergentol various solutions starting for the CHD 20, a root canals irrigating solution with a reason of 80% calcium hydroxide saturated solution and 20% tergentol detergent with the aim of evaluate this drug mouth rinse indication with prevention or combat objective for dental caries and periodontal diseases. Antibiogram disks and biofilm tests were accomplished for the microorganisms: Streptococcus mutans, Streptococcus sanguis, Streptococcus sobrinus and Lactobacillus casei. Different reasons of detergent for the calcium hydroxide saturated solution, tergentol and distillated water solution, 0,12% clorhexydine digluconate solution was positive control and distillated water was negative control. The results showed better performance of clorhexydine in relation to calcium hydroxide directing to not accept this (CHD20) as mouth rinse solution

Aspectos Microbiológicos e Demanda de Cloro de Amostras de Água de Dessedentação de Frangos de Corte Coletadas em Bebedouros Pendulares

Foram analisadas 72 amostras da água de dessedentação de frangos de corte, 18 da entrada e 54 dos bebedouros pendulares. As amostras foram submetidas às mensurações de coliformes totais, coliformes fecais, estreptococos fecais, Escherichia coli e organismos mesófilos, além da detecção da presença de Salmonella sp e da taxa de demanda de cloro. Os resultados evidenciaram uma elevada contaminação bacteriológica, já na primeira semana, com os indicadores na ordem de 10³ a 10(5). Não houve isolamento de nenhuma cepa de Salmonella sp, provavelmente por não haver ave infectada no plantel. A taxa de demanda de cloro mostrou-se elevada, devido ao maior acúmulo de matéria orgânica nos bebedouros, com o ápice na quinta semana (98,7%), seguida de uma leve diminuição na sexta semana (98,5%). As análises dos resultados evidenciam o bebedouro pendular como um instrumento depreciativo e ineficiente em relação às qualidades higiênico-sanitárias das águas fornecidas aos frangos de corte, contribuindo para um alto risco de contaminação por patógenos de veiculação hídrica. Preconizam-se a utilização de modelos de bebedouros menos deletérios e o monitoramento semanal de cloro residual nos bebedouros pendulares, a fim de se obter uma desinfecção satisfatória da água.

Qualidade Higiênico-Sanitária e Demanda de Cloro da Água de Dessedentação de Galinhas de Postura Coletadas em Bebedouros Tipo Nipple e Taça

O objetivo deste estudo foi avaliar a influência de dois tipos de bebedouros nipple e taça, utilizados na dessedentação de aves de postura e o incremento da demanda de cloro na água oferecida pelos dois tipos de bebedouros estudados. Foram realizadas as contagens de coliformes totais, coliformes fecais, Escherichia coli, estreptococos fecais e microrganismos mesófilos. Os resultados obtidos figuraram que as amostras de água dos reservatórios, de ambos os bebedouros, apresentaram-se contaminadas microbiologicamente antes de passarem pelos bebedouros. A contaminação por bactérias de poluição fecal foi maior nas amostras colhidas nos bebedouros tipo taça, assim como eles foram responsáveis por um maior acúmulo de matéria orgânica, tendo então uma elevada demanda de cloro e uma maior influência na depreciação da qualidade da água fornecida às aves. Dos dois tipos de bebedouros estudados, o tipo nipple mostrou ser o menos deletério no que concerne à qualidade da água entretanto, independente do tipo de bebedouro utilizado na dessedentação das aves, a desinfecção da água é um ato imprescindível à manutenção de sua qualidade e à eliminação de futuros patógenos.

A Nonstaining and Tasteless Hydrophobic Salt of Chlorhexidine

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)