Isolation of Pseudomonas aeruginosa strains from dental office environments and units in Barretos, state of São Paulo, Brazil, and analysis of their susceptibility to antimicrobial drugs

A wide variety of opportunistic pathogens has been detected in the tubing supplying water to odontological equipment, in special in the biofilm lining of these tubes. Among these pathogens, Pseudomonas aeruginosa, one of the leading causes of nosocomial infections, is frequently found in water lines supplying dental units. In the present work, 160 samples of water, and 200 fomite samples from forty dental units were collected in the city of Barretos, State of São Paulo, Brazil and evaluated between January and July, 2005. Seventy-six P. aeruginosa strains, isolated from the dental environment (5 strains) and water system (71 strains), were tested for susceptibility to six antimicrobial drugs most frequently used against P. aeruginosa infections. Susceptibility to ciprofloxacin, followed by meropenem was the predominant profile. The need for effective means of reducing the microbial burden within dental unit water lines is emphasized, and the risk of exposure and cross-infection in dental practice, in special when caused by opportunistic pathogens like P. aeruginosa, are highlighted.

Isolation of Pseudomonas aeruginosa strains from dental office environments and units in Barretos, state of São Paulo, Brazil, and analysis of their susceptibility to antimicrobial drugs

Uma ampla variedade de patógenos oportunistas tem sido detectadas nos tubos de alimentação de água dos equipos odontológicos, particularmente no biofilme formado na superfície do tubo. Entre os patógenos oportunistas encontrados nos tubos de água, Pseudomonas aeruginosa é reconhecida como uma das principais causadoras de infecções nosocomiais. Foram coletadas 160 amostras de água e 200 amostras de fomites em quarenta clinicas odontológicas na cidade de Barretos, São Paulo, Brasil, durante o período de Janeiro a Julho de 2005. Setenta e seis cepas de P. aeruginosa, isoladas a partir dos fomites (5 cepas) e das amostras de água (71 cepas), foram analisadas quanto à susceptibilidade à seis drogas antimicrobianas freqüentemente utilizadas para o tratamento de infecções provocadas por P. aeruginosa. As principais suscetibilidades observadas foram para a ciprofloxacina, seguida pelo meropenem. A necessidade de um mecanismo efetivo para reduzir a contaminação bacteriana dentro dos tubos de alimentação de água dos equipos odontológicos foi enfatizada, e o risco da exposição ocupacional e infecção cruzada na prática odontológica, em especial quando causada por patógenos oportunistas como a P. aeruginosa foi realçado.

Cutting characteristics of dental diamond burs made with CVD technology

The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD) diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding type of substrate (enamel and dentin) and direction of handpiece motion. The morphological characteristics, width and depth of the cavities were analyzed and measured using scanning electron micrographs. Statistical analysis using the Kruskal-Wallis test (p < 0.05) revealed that the width and depth of the cavities were significantly greater when they were prepared on dentin. Wider cavities were prepared when the cylindrical CVD bur was used, and deeper cavities resulted from preparation with the spherical CVD bur. The direction of handpiece motion did not influence the size of the cavities, and the CVD burs produced precise and conservative cutting.

Enrichment cultures should be performed in the detection of bacterial oral human pathogens in DUWLs

Water delivered by dental units during routine dental practice is densely contaminated by bacteria. The aim of this study was to determine actual isolation of the microorganisms sprayed from Dental Unit Water Lines (DUWLs) when enrichment cultures are performed and to compare frequencies with those obtained without enrichment cultures. Moreover, the antimicrobial susceptibilities of the microorganisms isolated were also studied. Water samples were collected from one hundred dental equipments in use at Dental Hospital of our University in order to evaluate the presence/absence of microorganisms and to perform their presumptive identification. Aliquots from all of the samples were inoculated in eight different media including both enrichment and selective media. Minimal inhibitory concentrations (MIC) were determined by the broth dilution method. The results herein reported demonstrate that most of the DUWLs were colonized by bacteria from human oral cavity; when enrichment procedures were applied the percentage of DUWLs with detectable human bacteria was one hundred percent. The results showed that in order to evaluate the actual risk of infections spread by DUWLs the inclusion of a step of pre-enrichment should be performed. The need for devices preventing bacterial contamination of DUWLs is a goal to be achieved in the near future that would contribute to maintain safety in dental medical assistance

Oral pathogens in duwl's: risk of infection and strategies for their control

Water lines are an important source of potentíal contamination. Every dental unit is equipped with small-bore flexible plastic tubing to bring water to different hand pieces, such as the air/water syringe, the ultrasonic scaler or the high-speed hand piece. Most dental units are connected directly to municipal distribution systems for potable water and chlorinated or not, this water contains diverse...

Amibes à potentiel pathogène dans les unités dentaires

Il a été bien documenté que les différentes canalisations des unités de soins dentaires contiennent un épais biofilm. Ce biofilm est constitué entre autres de bactéries, mais aussi d’amibes. Certaines amibes ont un potentiel pathogène et peuvent causer des infections graves. Deux cas d’infections amibiennes et possiblement reliées aux unités dentaires ont retenu notre attention et sont à l’origine du présent projet. L’identification morphologique des amibes afin de déterminer si elles présentent un potentiel pathogène ou non est une tâche ardue, même pour les protozoologistes chevronnés. Nous avons donc utilisé la réaction de polymérase en chaîne (PCR) pour identifier les amibes. Des nouvelles amorces ont été élaborées pour détecter les amibes des genres Acanthamoeba ainsi que Naegleria. Des échantillons d’eau et de terre ont été prélevés dans l’environnement, et des échantillons d’eau et de biofilm ont été prélevés dans les unités dentaires. Une partie de chaque échantillon a été mise en culture selon une méthode améliorée pour une identification morphologique, et l’autre partie a été soumise à un PCR direct. Des Acanthamoebae et/ou des Naegleriae ont été détectées dans 100% des échantillons, mais les espèces varient d’un échantillon à l’autre. Des amibes à potentiel pathogènes sont détectables dans les unités dentaires ainsi que dans l’environnement, et celles-ci pourraient représenter un risque pour la santé de certains individus.

Contaminação microbiana das soluções de processamento radiográfico: Risco de infecção cruzada

Objective: To evaluate the microbial contamination in samples of radiographic developing and fixing solutions, radiographic processing water, dental unit waterlines and dental office's external water supply. Methods: Samples of 50 private dental offices and 20 dental offices of the School of Dentistry de Araçatuba-UNESP were collected. The samples were subjected to neutralization of the residual inhibitory agents followed by pre-enrichment in peptone water and EVA broth and were inoculated in selective and non-selective culture media. The DNA of the samples was extracted and the presence of superinfectant microorganisms was evaluated by PCR. The differences in the prevalence of the microorganisms in the samples of the solutions were analyzed by repeated-measures analysis of variance for category data, while the Chi-Square and Mann-Whitney tests were used to evaluate the existence of associations between the total number of heterotrophic microorganisms and infection control protocols. The significance level was set at 5%. Results: Samples of radiographic fixing solution presented a remarkably less frequent contamination than radiographic developing solution and radiographic processing water. The latter exhibited microorganisms typically originated from the oral microbiota and human skin as well as microorganisms frequently found in dental unit waterlines. There was less contamination of radiographic processing water in the dental offices where the x-ray film packets were disinfected before processing or were covered by a plastic film. Additionally, all samples of dental office's external water supply were drinkable. Conclusion: Covering the x-ray film packets with a plastic film protection barrier was proven the best manner to reduce the contamination of the evaluated solutions.

Percepção do cirurgião-dentista da rede pública de saúde sobre as condições de trabalho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contaminación microbiana en las líneas de agua de las unidades odontológicas

Introduction and Objective: Microorganisms are responsible for multiple infections and pathologies; this is why it is important to control microbes that can be found in the triple syringe used for irrigation in different dental procedures. The aim of this study was to identify cultivable species of microbes (fungus and bacteria) found in some dental units water lines of a private dental clinic from Medellín, Colombia. Materials and Methods: Random samples were taken from 11 chairs from a total of 89; a sample of water of 500ml was collected from the triple syringe of each selected chair. The study aim to search for the presence of total coliforms, filamentous fungi and leavened Results: the average presence of microorganisms was between 40CFU and more of 200 CFU. Microorganisms such as Aeromona salmonicida, Actinobacilus sp and Pseudomona maltophil were isolated. No total coliforms neither fecal coliforms were found. Conclusions: the high levels of contamination suggest that there is a mature biofilm in somewhere of the dental unit water line, but the absence of total and fecalis coliforms suggest that the water had been treated.

Percepção de pacientes HIV-positivos de um centro de referência em relação a tratamento de saúde

Introduction: health professionals, in many cases, have defensive and exclusionary practices, patterns of prejudice and discrimination in response to HIVpositive patients. Objective: to verify the perception of patients seropositives from a reference center for STD/HIV/aids in relation to health care. Methods: there were interviews with questions related to discriminatory attitudes suffered, access and health care. Results: 130 individuals participated in the survey, from which 30 (23.1%) reported events of discrimination suffered outside the center of reference, predominantly from surgeon-dentists and 112 (86.2%) believed to have the same access and health care as other citizens. 62 (47.7%) treated with the dental center of reference, of which 56 (90.3%) felt good being treated in a dental unit only for HIV positive and six (9.7%) were indifferent, believed to be more exposed, or have a bias to attend dental seropositive individuals. Conclusion: it is concluded that many patients have already been discriminated against outside the reference center. However, most of them have a positive feeling towards the treatment received at a specifi c place for treating HIV-positive patients, due to the feeling of being welcome at that place due to the humanization and access to health care.

Depth of cure and surface microhardness of composite resin cured with blue LED curing lights

Objectives. This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available tight emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). Methods. The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. Results. HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH tights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. Significance. Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing. (C) 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of the Light-Curing Unit, Storage Time and Shade of a Dental Composite Resin on the Fluorescence

The aim of this study was to determine the influence of three light-curing units, storage times and colors of the dental composite resin on the fluorescence. The specimens (diameter 10.0 +/- 0.1 mm, thickness 1.0 +/- 0.1 mm) were made using a stainless steel mold. The mold was filled with the microhybrid composite resin and a polyethylene film covered each side of the mold. After this, a glass slide was placed on the top of the mold. To standardize the top surface of the specimens a circular weight (1 kg) with an orifice to pass the light tip of the LCU was placed on the top surface and photo-activated during 40 s. Five specimens were made for each group. The groups were divided into 9 groups following the LCUs (one QTH and two LEDs), storage times (immediately after curing, 24 hours, 7 and 30 days) and colors (shades: A(2)E, A(2)D, and TC) of the composite resin. After photo-activation, the specimens were storage in artificial saliva during the storage times proposed to each group at 37 C and 100% humidity. The analysis of variance (ANOVA) and Tukey's post-hoc tests showed no significant difference between storage times (immediately, 24 hours and 30 days) (P > 0.05). The means of fluorescence had difference significant to color and light-curing unit used to all period of storage (P < 0.05). The colors had difference significant between them (shades: A2D < A2E < TC) (P < 0.05). The Ultraled (LED) and Ultralux (QTH) when used the TC shade showed higher than Radii (LED), however to A2E shade and A2D shade any difference were found (P > 0.05).