Eficácia de agentes químicos na desinfecção de tubetes anestésicos odontológicos / Effectiveness of chemical agents in disinfecting dental anesthetic cartridges

Durante o atendimento odontológico, o paciente pode ser exposto a várias fontes de contaminações, por isso a equipe odontológica deve sempre implementar ações de biossegurança. Materiais não autoclaváveis, como os tubetes anestésicos, necessitam ser desinfetados previamente ao seu uso, pois não são estéreis, podendo transmitir patógenos entre os pacientes. Este estudo objetivou avaliar e comparar a eficácia de três soluções desinfetantes na redução da carga microbiana em tubetes de anestésicos odontológicos. Os tubetes anestésicos (n = 31) foram escolhidos aleato-riamente e submetidos a diferentes métodos e agentes desinfetantes (Álcool 70%, Dióxido de Cloro 7%; Cloreto de benzalcônio 5,2% com Polihexametileno biguanida 3,5%). Após a desinfecção por métodos de imersão ou fricção, os tubetes foram semeados em meio de cultura contendo caldo tripticase de soja e incubados (48h/37 ºC). Amostras do meio de cultura líquido foram repicadas e semeadas em ágar tripticase de soja, incubado durante 48h a 37 ºC. O crescimento microbiano foi observado pela presença de unidades formadoras de colônias (UFCs) crescidas no ágar. O estudo concluiu que os produtos Álcool 70% e Cloreto de benzalcônio 5,2% com Polihexametileno biguanida 3,5% demostraram ser mais eficazes na eliminação da carga microbiana dos tubetes pelo método de fricção, e que realmente os tubetes anestésicos tem sua superfície externa contaminada. O estudo comprovou ser o método de fricção do agente desinfetante mais eficaz na redução da carga microbiana comparado a imersão. Dos agentes testados, o Dióxido de Cloro 7% não demonstrou um nível de desinfecção satisfatório.

During dental care, the patient may be exposed to various sources of contamination, so the dental team should always implement biosecurity actions. Non-autoclavable materials such as anesthetic cartridges need to be di-sinfected prior to use because they are not sterile and can transmit pathogens between patients. This study aimed to evaluate and compare the effectiveness of three disinfectant solutions to reduce microbial load in dental anesthetic cartridges. Anesthetic cartridges (n = 31) were randomly chosen and submitted to different methods and disinfectants (70% Alcohol, 7% Chlorine Dioxide; 5.2% Benzalkonium Chloride with 3.5% Polyhexamethylene Biguanide). After immersion or friction methods of disinfection, the tubes were seeded in culture medium containing trypticase soy broth and incubated (48h/37 ºC). Samples of liquid culture medium were picked and seeded in trypticase soy agar, incubated for 48h at 37 ºC. Microbial growth was observed by the number of colonies forming units (CFUs) grown on the agar. The study concluded that 70% Alcohol and 5.2% Benzalko-nium Chloride with 3.5% Polyhexamethylene biguanide have been shown to be most effective in eliminating the microbial contamination of the cartridges by the friction method, and that the anesthetic cartridges actually have contamination of their external surface. The study proved that the friction method is most effective in reducing microbial load compared to immersion. Of the agents tested, 7% Chlorine Dioxide did not show a satisfactory level of disinfection.

Desinfección del instrumental en las Unidades de Salud Bucodental del Servicio Gallego de Salud / Disinfection of dental instruments in dental settings of the Galician Health Service

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Some factors influencing the stability of Sterilox(®), a super-oxidised water.

Super-oxidised waters, particularly Sterilox(®), have been suggested for the disinfection of dental unit water lines and dental impression materials owing to their antimicrobial efficacy. One of the previously suggested characteristics is their short shelf life. The purpose of this investigation was to understand the effect of storage conditions on Sterilox(®)'s stability. Eight bottles (four completely full, four half-full) of freshly prepared solution were divided into four groups and subsequently stored by being either exposed to or protected from sunlight. The chlorine concentration was monitored using chlorine test strips until the concentration reached zero, or until the thirteenth week. Statistically significant differences between the groups exposed to sunlight and the non-exposed groups (p <0.001) were found. The mean loss of chlorine per day for the non-exposed samples was 1.01 mg/L, whilst the mean for the exposed samples was 2.42 mg/L. The presence of air did not affect the chlorine decomposition in the bottles. The results of this investigation indicate that when the solution is exposed to sunlight, the decrease of chlorine starts at day 4, whilst for the groups sheltered from sunlight, the process started after day 14. Therefore, Sterilox(®) solutions appear to be more stable than previously surmised.

In vitro investigation of the integration depth of oral fluids and disinfectants into alginate impressions.

THE OBJECTIVE: The objective of this work is to prove that oral cavity fluids diffuse into alginate mass of impressions. In addition, the information is presented on the subject that disinfectants used for alginate impressions disinfection not only diffuse into alginate mass but penetrate deeper than oral cavity fluids. MATERIALS AND METHODS OF THE STUDY: Three examination groups were formed for the research, the results of which evidenced how deeply oral cavity fluids and disinfectants 'Alpha Guard GF' and 'Orbis' could possibly diffuse into alginate impression material 'Kromopan 100'. In the first examination group ten impressions from the upper jaw dental arch and mucosa were taken, firstly colouring oral cavity fluids with a special colouring tablet MIRA-2-TON (Hager Werken). Cuts were randomly selected from impressions and scanned aiming to establish the depth of the coloured oral cavity fluid penetration. In the second and the third examination groups taken alginate impressions were accordingly soaked in 'Alpha Guard GF' and 'Orbis' with pigment and later randomly selected cuts were scanned in the same manner as in the first research group. RESULTS. The research results establish that coloured dental cavity fluids maximum diffuse into alginate impression is up to 540 microm with the presence of 95% of discolouring while disinfectants 'Alpha Guard GF' and 'Orbis' accordingly diffuse into alginate mass up to 710 microm and 870 microm with the presence of 95% of discolouring. CONCLUSIONS. The results obtained show that disinfectants using them according to the recommendations of a manufacturer, diffuse into alginate mass deeper than oral cavity fluids at the time of impressions taking.

Ozone air levels adjacent to a dental ozone gas delivery system.

OBJECTIVE: Ozone (O3) has been suggested as an anti-microbial treatment in dentistry, with an ozone gas delivery system introduced for the treatment of fissure and root caries. The aim of this study was to investigate the sealing capacity of the novel delivery system and its re-suction capacity during accidental displacement of the cup at different stages of ozone delivery. MATERIAL AND METHODS: Ozone leakage was studied in vitro after application on a flat metal surface and on buccal and occlusal tooth surfaces. An ozone analyzer was used to measure ozone gas concentrations adjacent to the delivering cups when adapted to the target surfaces during and after 10-20 s application cycles. The measured levels were compared with the background concentrations in the room. Measurements were performed 1) after complete ozone application cycles, 2) within the cycle before the start of the suction period, and 3) after displacements of the cup during the cycles. RESULTS: Ozone air values varied between 8 and 166 microgram/meter-3 for the flat metal surface and between 0 and 108 microgram/meter-3 for the tooth surfaces. Ozone leakage levels were 7.6 microgram/m-3 for the flat and and 7.4 microgram/meter-3 and 5.6 microgram/meter-3 for the buccal and occlusal surfaces, respectively, and 5.2 microgram/meter-3 and 9.8 microgram/meter-3 for the premolar and molar surfaces, respectively. Cycles with displacement showed significantly higher leakage levels than continuous complete cycles (p=0.03). CONCLUSIONS: Ozone application cycles with displacements showed significantly higher leakage levels than continuous complete cycles. The largest ozone delivery cups showed the highest leakage values. A change in background levels was seen with similar change in adjacent ozone levels. The overall measured ozone leakage values were low after normally functioning delivery cycles and after repeated displacements. The delivery system can be considered safe.

Analysis of three disinfectants after immersion of irreversible hydrocolloid and ZOE paste impressions

This investigation sought to analyze 3 disinfectants: 0.5% chlorhexidine, 2% glutaraldehyde, and 1% sodium hypochlorite after immersion of irreversible hydrocolloid and zinc oxide-eugenol paste impressions. Changes detected in the solutions could suggest alterations in the dental impressions, compromising their quality and negatively influencing treatment outcome. Forty-five irreversible hydrocolloid impressions (Jeltrate) made in aluminum stock impression trays (AG) as well as 45 irreversible hydrocolloid and 45 zinc oxide-eugenol paste (Horus) impressions made in auto polymerizing acrylic resin (AAR) trays (VipiFlash) were immediately immersed in 200mL of 0.5% chlorhexidine (Labfa), 2% glutaraldehyde (Glutaron II), or 1% sodium hypochlorite ( Miyako) solutions for 10, 30, and 60 minutes. After immersion the solutions were analyzed by visible ultraviolet spectroscopy and turbidimetry to verify possible alterations. Turbidimetry (registered in nephelometric turbidity units -NTU) results were subjected to Kruskal-Wallis and Mann-Whitney tests for statistical analysis (á=.05). An increase of absorption levels of all disinfectants was found after immersion of irreversible hydrocolloid impressions. This increase was proportional to time of immersion and absorption was higher for 0.5% chlorhexidine for the 3 time periods analyzed. Only 1% sodium hypochlorite presented statistically significant alterations after immersion of zinc oxideeugenol paste impressions.

Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red.

A novel, simple, rapid, sensitive and highly selective flow injection procedure for the spectrophotometric determination of chlorine dioxide in the presence of other chlorine species, viz, free chlorine, chlorite, chlorate and hypochlorite, is developed. The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct spectrophotometric determination for chlorine dioxide owing to the serious interference of free and combined chlorine. The procedure gave a linear calibration graph over the range 0-0.71 mg/L of chlorine dioxide. With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.

Avaliaçäo de desinfetantes de superfície utilizados em odontologia / Evaluation of surface disinfectants utilized in dentistry

Desinfecçäo de superfície é um procedimento realizado nas áreas externas do equipamento odontológico e demais itens do consultório. O objetivo deste trabalho foi analisar a açäo de quatro desinfetantes utilizados em Odontologia: álcool etílico 77 GL, composto fenólico (Duplofen), iodóforo (PVP-I) e soluçäo de álcool etílico a 77 GL com 5 por cento de clorexidina para desinfecçäo de superfície. Foram analisados quatro pontos em cada equipamento (carter, pia de lavagem de mäos, encosto de cabeça da cadeira e superfície frontal externa do refletor), utilizando-se a técnica de spray-wipe-spray. De cada ponto, foram coletadas amostras utilizando-se placas de superfície contendo ágar Mitis Salivarius bacitracina sacarose, ágar Sabouraud Dextrose com cloranfenicol, ágar MacConkey e ágar sangue para contagem de estreptococos do grupo mutans, leveduras do gênero Candida, bactérias Gram-negativas e contagem total de microrganismos, respectivamente (ufcplaca). Os resultados foram analisados estatisticamente utilizando-se teste t de Student para comparaçäo entre as médias de ufc/placa. O desinfetante que demonstrou ser mais efetivo na reduçäo microbiana foi a soluçäo alcoólica de clorexidina, principalmente para bactérias Gram-positivas. O iodo e o composto fenólico mostraram ser bastante eficazes na reduçäo microbiana. O álcool etílico a 77 GL foi o menos eficaz dos quatro desinfetantes analisados, mas apesar de näo ser indicado como desinfetante de superfície, mostrou, no presente trabalho, reduçäo microbiana estatisticamente significativa após o processo de desinfecçäo