Protocolo com produtos químicos para o enfrentamento do biofilme em linhas d'água de equipos odontológicos: perspectiva física, química, mecânica e biológica / Protocol with chemical products to combat biofilm on dental unit waterlines: physical, chemical, mechanical, and microbiological perspective

A biossegurança na odontologia visa o enfrentamento da contaminação cruzada e o biofilme em linhas d'água de equipos odontológicos. O objetivo deste estudo foi investigar, na perspectiva física, química, mecânica e biológica, um protocolo de uso de produtos químicos com possível aplicabilidade nas linhas d'água de equipos odontológicos para melhoria e manutenção da qualidade da água. O protocolo com produtos químicos (Produto A - ácido cítrico + cloreto de sódio; Produto B - bicarbonato de sódio + cloreto de sódio; Produto AB - ácido cítrico + bicarbonato de sódio + cloreto de sódio) foi empregado em corpos de prova de aço inoxidável que, posteriormente, foram submetidos aos ensaios de microdureza e corrosão. Ainda, ensaios de cor, microdureza, rugosidade e de atividade antibiofilme [biomassa total (cristal violeta), atividade metabólica (XTT), viabilidade por meio de corante fluorescente e microscopia confocal de varredura à laser, bem como morfologia estrutural do biofilme por microscopia eletrônica de varredura (MEV)] foram realizados em corpos de prova de poliuretana. As cepas padrão empregadas para avaliar a atividade antibiofilme monoespécie foram Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 29923) e Escherichia coli (ATCC 25922). Com relação à alteração da microdureza no aço inoxidável, após a imersão simulada por 1 e 2 anos nos Produtos (A+B+AB), não houve diferença dos resultados com o grupo controle (água). Decorrida a exposição aos produtos e grupo controle, a maioria das amostras de aço inoxidável apresentou tendência à corrosão. Ainda, houve alterações de cor, microdureza e rugosidade nas superfícies de poliuretana após a imersão simulada por 1 e 2 anos dos produtos e do grupo controle. A avaliação da biomassa dos biofilmes indicou que o Produto A (p=0,003) e o Produto AB (p=0,019) reduziram significativamente o biofilme de P. aeruginosa em comparação com o controle. Por outro lado, a avaliação da biomassa do biofilme formado por S. aureus sugeriu que o Produto B (p=0,018) promoveu maior ação antibiofilme. Em relação aos biofilmes formados por E. coli, o Produto A (p=0,001) e o uso sequencial dos Produtos A+B+AB (p=0,021) mostraram os melhores resultados. Para o XTT em comparação com o controle, os tratamentos com o Produto A (p=0,001), o Produto AB (p<0,001) e o uso sequencial dos Produtos A+B+AB (p=0,002) reduziram significativamente a atividade metabólica do biofilme de P. aeruginosa. No biofilme formado por S. aureus, contrariando os resultados observados na avaliação da biomassa, o Produto B não promoveu alterações significantes na atividade metabólica (Produto A: p<0,001; Produto AB: p=0,007; uso sequencial dos Produtos A+B+AB: p<0,001). Considerando o biofilme formado por E. coli, observou-se que o Produto B (p=0,046), o Produto AB (p<0,001) e o uso sequencial dos Produtos A+B+AB (p<0,001) promoveram redução da atividade metabólica. Observou-se redução significativa do biofilme total após o emprego dos produtos (p<0,001), em relação ao controle. Apesar da redução significativa, ainda se observou agregados de biofilme residual, cobrindo extensa porção das superfícies, mesmo após o uso dos produtos. Considerando a quantidade de células vivas de P. aeruginosa e E. coli, o Produto A e o Produto B, isolados ou em conjunto demostraram resultados semelhantes. Além disso, o Produto AB e o uso sequencial dos Produtos A+B+AB não promoveu diferença na quantidade de células vivas de S. aureus, em comparação ao controle, indicando que a combinação dos produtos não potencializou a atividade antibiofilme. Em conclusão, os produtos analisados nesta pesquisa mostraram potencial inovador para o enfrentamento do biofilme linha d'água dos equipos odontológicos, preservando as propriedades físicas, químicas e mecânicas dos materiais.

Biosafety in dentistry aims to combat cross-contamination and biofilm on dental unit waterlines. The aim of this study was to investigate, from a physical, chemical, mechanical, and biological perspective, a protocol for the use of chemical products with possible applicability in dental unit waterlines to improve and maintain water quality. The protocol with chemicals (Product A - citric acid + sodium chloride; Product B - sodium bicarbonate + sodium chloride; Product AB - citric acid + sodium bicarbonate + sodium chloride) was used in stainless steel specimens which, later, were subjected to microhardness and corrosion tests. Moreover, color, microhardness, roughness and antibiofilm activity tests [total biomass (crystal violet), metabolic activity (XTT), viability by means of fluorescent dye and confocal laser scanning microscopy, as well as structural morphology of biofilm by scanning electron microscopy (SEM)] were performed on polyurethane specimens. The standard strains used to assess monospecies antibiofilm activity were Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 29923) and Escherichia coli (ATCC 25922). Regarding the microhardness change in stainless-steel, after simulated immersion for 1 and 2 years in Products (A+B+AB), there was no difference in the results with the control group (water). After exposure to the products and control group, most stainless-steel samples showed a tendency to corrosion. Furthermore, there were changes in color, microhardness, and roughness on the polyurethane surfaces after simulated immersion for 1 and 2 years of the products and the control group. Biofilm biomass evaluation indicated that Product A (p=0.003) and Product AB (p=0.019) significantly reduced P. aeruginosa biofilm compared to the control. On the other hand, the evaluation of the biomass of the biofilm formed by S. aureus suggested that Product B (p=0.018) promoted greater antibiofilm action. Regarding biofilms formed by E. coli, Product A (p=0.001) and the sequential use of Products A+B+AB (p=0.021) showed the best results. For XTT compared to the control, treatments with Product A (p=0.001), Product AB (p<0.001) and sequential use of Products A+B+AB (p=0.002) significantly reduced metabolic activity from the biofilm of P. aeruginosa. In the biofilm formed by S. aureus, contrary to the results observed in the biomass assessment, Product B did not promote significant changes in metabolic activity (Product A: p<0.001; Product AB: p=0.007; sequential use of Products A+B+ AB: p<0.001). Considering the biofilm formed by E. coli, it was observed that Product B (p=0.046), Product AB (p<0.001) and the sequential use of Products A+B+AB (p<0.001) promoted a metabolic activity reduction. There was a significant reduction in the total biofilm after using the products (p<0.001), compared to the control. Despite the significant reduction, residual biofilm aggregates were still observed, covering a large portion of the surfaces, even after using the products. Considering the amount of living cells of P. aeruginosa and E. coli, Product A and Product B, alone or together, showed similar results. In addition, Product AB and the sequential use of Products A+B+AB did not promote difference in the amount of living S. aureus cells, compared to the control, indicating that the combination of products did not enhance the antibiofilm activity. In conclusion, the products analyzed in this research showed innovative potential for facing the biofilm on dental unit waterline, preserving the physical, chemical, and mechanical properties of the materials.

The Optimum Duration of Flushing Dental Unit Waterlines for Microbial Removal

ABSTRACT@#This study aims to evaluate the optimum duration of flushing dental unit waterlines (DUWLs) in Universiti Sains Islam Malaysia (USIM) dental polyclinics for removal of heterotrophic bacteria. Water samples were obtained from triple air syringes at each dental chair from oral surgery clinic, outpatient clinic and polyclinic 17 at Faculty of Dentistry, USIM after 16 and 64 hours of not operating the dental units as baseline samples. This is followed by sampling after continuous flushing at 30 seconds, 1 minute, 2 minutes and 3 minutes of flushing duration. The levels of heterotrophic plate count (HPC) for each flushing duration were determined by quantification of colony forming units (CFUs) after cultivation of samples on plate count agar (PCA), R2A agar and 5% sheep blood agar (SBA). Statistically, there was no significant reduction in CFUs of HPC for all flushing duration compared to baseline (P > 0.05) with the most notable HPC reducing level after 1 minute and 3 minutes of flushing DUWLs. However, HPC level at USIM dental clinics is still exceeding the recommendation by Centers for Disease Control and Prevention (CDC) which should be less than 500 CFU/mL. The existing method of controlling DUWLs contamination in USIM dental clinics is only by flushing DUWLs 1 minute every morning prior to dental treatment as recommended by Malaysian Dental Council (MDC) without the use of chemical germicides. Thus, the flushing method alone is not reliable to reduce the number of microorganisms in the DUWLs.

Comparative evaluation of chlorhexidine and cinnamon extract used in dental unit waterlines to reduce bacterial load in aerosols during ultrasonic scaling

Dental unit waterlines (DUWL) are believed to be a source of infection. Ultrasonic instruments generate aerosols with significantly greater numbers of bacteria. Chlorhexidine (CHX) exhibits significant antiseptic effect. Recently, cinnamon (CIN) has been displayed to have antibacterial and anti-inflammatory properties in vivo. Aim: The aim of this study is to compare and evaluate the efficacy of CHX versus CIN extract in the reduction of bacterial count in dental aerosols when used as an irrigant through DUWL during ultrasonic scaling. Materials and Methods: Sixty patients with moderate-to-severe gingivitis were randomly divided into 3 groups of 20 patients each undergoing ultrasonic scaling. For experimental group I, CHX was added in dental unit reservoir before ultrasonic scaling. Similarly, in group II, CIN extract was used and group III served as control where distilled water (DW) was used. The aerosols from ultrasonic units were collected on two blood agar plates at three different positions. One plate from each position was incubated aerobically for 48 h and other plate anaerobically for 72 h. The total number of colony forming units (CFUs) was then calculated and statistically interpreted. Results: CHX and CIN both were equally effective (P > 0.05) in reducing the bacterial count in aerosols as compared to DW (P < 0.05) when used through DUWL. Maximum contamination was seen on the agar plate placed at the chest of the patient. Conclusion: Both CIN and CHX used as an irrigant through DUWL effectively helped in the reduction of bacterial count in dental aerosols.

Slightly acidic electrolyzed water cytotoxicity to oral keratinocyte monolayers / 口腔疾病防治

Objective @#To investigate the cytotoxicity of slightly acidic electrolyzed water (SAEW) on oral keratinocyte monolayers. @*Methods@#TR146 human keratinocyte monolayers were exposed to SAEW pretreated with bovine serum albumin（BSA）. It was divided into 4 groups, BSA 0 mg/mL (SAEW stock solutsion), BSA 0.5 mg/mL, BSA 1 mg/mL and BSA 2 mg/mL. The relative growth rate (RGR) was measured using a CCK-8 assay at 1 min, 5 min, 15 min, 30 min and 1 h, and the survival rate was measured using a Trypan Blue exclusion assay at 1 h. @*Results@#The CCK-8 assay showed significantly different OD values in the SAEW and negative control groups at different times and FAC concentrations (P<0.05). With increasing FAC concentrations and observation times, the RGR in the SAEW group decreased, and the SAEW showed moderate to severe cytotoxic effects. The OD values in the BSA (0.5~2 mg/mL)-pretreated SAEW and negative control groups were not significantly different at different times or FAC concentrations (P > 0.05); the RGRs of the BSA-pretreated SAEW group all approached 100%, and no cytotoxic effects were observed in the BSA-pretreated SAEW group. The Trypan Blue exclusion assay showed significantly different survival rates in the SAEW and negative control groups at different FAC concentrations (P < 0.05). As the FAC concentration increased, the survival rate in the SAEW group decreased, and SAEW showed moderate to severe cytotoxic effects. The survival rates in the BSA-pretreated SAEW and negative control groups were not significantly different at different FAC concentrations (P > 0.05); the survival rates in the BSA-pretreated SAEW group all approached 100%, and no cytotoxic effects were observed.@*Conclusion@#SAEW showed no adverse effects on the viability of dental oral keratinocyte monolayers in vitro in the presence of BSA at concentrations equivalent to that of protein in saliva.

Qualidade da água em clínica odontológica na perspectiva microbiológica: uma proposta de intervenção / Water quality in a dental clinic in the microbiological perspective: a proposal of intervention

Na odontologia, o biofilme formado nas linhas d'água de equipos odontológicos pode disseminar a contaminação microbiana na água. O objetivo desta pesquisa foi investigar a contaminação microbiana da água de abastecimento e de equipos odontológicos antes e após a implementação de um protocolo para melhoria e manutenção da qualidade microbiológica da água de equipos odontológicos, bem como desenvolver produtos antibiofilme com possível aplicabilidade nas linhas d'água. A carga microbiana da água de 27 torneiras e equipos (reservatórios, seringas tríplice e alta rotação) de uma clínica odontológica foi avaliada por meio do sistema Petrifilm(TM) (bactérias aeróbias totais e fungos) e meios de cultura convencionais (enterobactérias e Legionella spp.) em duas etapas distintas, sendo a segunda análise realizada após a implementação de um protocolo para melhoria e manutenção da qualidade microbiológica da água dos equipos. Ainda, as atividades antibacteriana (concentração inibitória mínima - hipoclorito de sódio, ácido cítrico, bicarbonato de sódio, cloreto de sódio, dodecil sulfato de sódio, peróxido de hidrogênio, polissorbato 20 e quitosana) e antibiofilme (biomassa total e viabilidade celular) foram determinadas in vitro a partir de substâncias e produtos com possível aplicabilidade na desinfecção de linhas d'água de equipos. As amostras de água das torneiras apresentaram carga bacteriana dentro do parâmetro estabelecido pela legislação brasileira, no entanto, as seringas tríplices e os alta rotação não. A implementação do protocolo para manutenção da qualidade microbiológica da água dos equipos demonstrou uma redução nas cargas bacteriana e fúngica apenas nos alta rotação. Enterobactérias e Legionella spp. não foram isoladas das amostras de água das torneiras e dos equipos. De acordo com a concentração inibitória mínima, o ácido cítrico, bicarbonato de sódio, cloreto de sódio, hipoclorito de sódio e peróxido de hidrogênio demonstraram as melhores atividades antibacterianas. As melhores atividades antibiofilme (biomassa total) foram do peróxido de hidrogênio a 5% (E. coli e P. aeruginosa), ácido cítrico a 30% (P. aeruginosa) e bicarbonato de sódio a 30% (S. aureus). Os produtos (Wanitox A e Wanitox B) desenvolvidos apresentaram atividade antibiofilme (viabilidade celular) contra a E. coli e S. aureus. Assim, os produtos desenvolvidos nesta pesquisa apresentaram possível aplicabilidade no enfrentamento do biofilme nas linhas d'água de equipos odontológicos, que permanece como um dos grandes desafios na odontologia. Ainda, pesquisas adicionais são necessárias para o aperfeiçoamento e aplicabilidade destes produtos

In dentistry, biofilm formed on dental unit waterlines can disseminate microbial contamination in water. The objective of this research was to determine the microbial contamination of water from supplies and dental units before and after the implementation of a protocol for improvement and maintenance of microbiological water quality of water from dental units as well as to develop antibiofilm products with possible applicability in waterlines. The microbial load of water from 27 taps and dental units (reservoirs, air-water syringes and high-speed turbines) in a dental clinic was evaluated through a Petrifilm(TM) system (total aerobic bacteria and fungi) and conventional culture mediums (enterobacteria and Legionella spp.) in two distinct stages, being the second analysis performed after the implementation of a protocol for improvement and maintenance of microbiological water quality of water from dental units. Moreover, the antibacterial (minimum inhibitory concentration - sodium hypochlorite, citric acid, sodium bicarbonate, sodium chloride, sodium dodecyl sulfate, hydrogen peroxide, polysorbate 20 and chitosan) and antibiofilm (total biomass and cell viability) activities were determined in vitro from substances and products with possible applicability in disinfection of dental unit waterlines. The water samples from taps presented bacterial load within the parameter established by Brazilian legislation; however, air-water syringes and high-speed turbines did not. The protocol implementation for maintenance of microbiological water quality of water from dental units showed a decrease on bacterial and fungal loads only on high-speed turbines. Enterobacteria and Legionella spp. were not isolated from water samples from taps and dental units. According to minimum inhibitory concentration, citric acid, sodium bicarbonate, sodium chloride, sodium hypochlorite and hydrogen peroxide showed the best antibacterial activities. The best antibiofilm activities (total biomass) were from 5% hydrogen peroxide (E. coli and P. aeruginosa), 30% citric acid (P. aeruginosa) and 30% sodium bicarbonate (S. aureus). The developed products (Wanitox A and Wanitox B) showed antibiofilm activity (cell viability) against E. coli and S. aureus. Thus, the products developed in this research presented a possible applicability in confrontation with biofilm on dental unit waterlines, and this remains as a major challenge in dentistry. Besides, additional researches are necessary for enhancement and applicability of these products

Efficacy of aseptic processing on dental unit waterlines / 中国感染控制杂志

Objective To compare the effect of different ways of water supply and whether or not drain water from waterlines for overnight on bacterial counts in dental unit waterlines(DUWLs).Methods In the first phase,6 sets of DUWLs were randomly divided into 2 groups (external storage tank water supply group and municipal water sup-ply group);in the second phase,6 sets of DUWLs were all changed to use external storage tank and randomly di-vided into 2 groups (draining water for overnight group and without draining water for overnight group),bacterial count before and within one week of disinfection between two groups at two phases were compared respectively. Results In the first phase,handpiece water of DUWLs was most seriously contaminated by bacteria,the average colony count was 4117 CFU/mL,qualified rate was 15.38%.Before disinfection,no significant difference in bacte-rial count were found among each groups (all P>0.05),bacterial count of DUWLs of all groups severely exceeded the standard(all >3000 CFU/mL).Comparison of bacterial count in DUWLs from different water supply routes after disinfection was not significantly different on day 1(P>0.05),but were significantly different at day 2-7(all P0.05),but were significantly different on day 2-7(all P100 CFU/mL.Conclusion Use of external storage tank,daily change of sterile distilled water,and daily emptying water for overnight can effectively reduce bacterial count in DUWLs.

Dental unit water lines decontamination with the aid of nanotechnology.

Aim: This article reviews the issue of dental unit waterline (DUWL) contamination which affects all the clinical and hospital settings. The contaminating microorganisms commonly isolated from these settings and the most pathogenic among them have serious consequences. Over the years several measures are inculcated for decontamination of water, their advantages and shortcomings have been addressed. Options using nanotechnology which are available in the market are described briefly. Materials and Methods: A manual and electronic search was conducted. Google and PubMed were searched for relevant material from studies up to 2013. Medical Subject Headings words looked for were “Nanotechnology,” “Water purification,” and “Biofilms.” Reviewed findings were summarized by topic, using the Preferred Reporting Items for Systematic Reviews and Meta‑analyses statement for reporting. Seventy articles were shortlisted for articles pertaining to our topic of discussion. A systematic approach was followed by two independent reviewers and included eligibility criteria for study inclusion, data extraction, data synthesis, and drawing of conclusion. Results: Dental waterline contamination is widespread in any type of dental setting having serious implications on clinicians and patients alike, especially elderly and immune‑compromised. Hence, international bodies like center for disease and control and American Dental Association have come up with stringent measures for maintenance of water quality. A gamut of procedures has been tried to overcome this problem ranging from chlorinated products, water filters to the usage of distilled water. The use of nanoemulsions, nanofilters, nanomembranes, etc., and their applicability for routine usage is discussed. Conclusions: Biofilm formation in DUWLs is inevitable with the subsequent release of part of microbiota into the otherwise sterile dental settings. These consequences can be quite serious on clinicians and dental patients. Though conventional measures in water decontamination have been partly successful, the quest for more foolproof methods has led to the use of latest technology, i.e., nanotechnology. The most practical option has to be chosen based on the ease of their usage.

Disinfection efficacy of different disinfectants on dental unit waterlines / 中国感染控制杂志

Objective To compare the disinfection efficacy of different disinfectants on dental unit waterlines (DUWLs). Methods 18 sets of DUWLs were randomly divided into 4 groups,and disinfected or treated with hydrogen peroxide (H2 O2 )disinfectant,sodium hypochlorite (NaClO)disinfectant,hydrogen peroxide silver ion disinfectant(Sanosil),and distilled water (DW)respectively.Water specimens from triple syringes and high-speed handpieces were taken,bacterial count before and after disinfection were compared.Results Before disinfection,no significant differences in bacterial counts were found among four groups (all P >0.05),bacterial counts of DUWLs of all groups severely exceeded the standard(all>3 000 CFU/mL).After disinfection,except DW group,bacterial counts of DUWLs of the other groups declined dramat-ically (all <100 CFU/mL),bacterial count after disinfection were all obviously lower than before disinfection (all P <0.001 ).One week after disinfection,bacterial counts among three disinfectant groups in different time periods were statisti-cally different (triple syringes:Day1—Day5,all P <0.05;high-speed handpieces:Day2,Day3 and Day5,all P <0.05). Day3 after disinfection of triple syringes by H2 O2 and NaClO,Day4 after disinfection of high-speed handpieces by H2 O2 and NaClO,and Day5 of triple syringes and high-speed handpieces by Sanosil all exceeded the standard of Center for Disease Control and Prevention of America.One week after disinfection,bacterial counts of three disinfection groups all exceeded or approximated to that before disinfection.Conclusion Three types of disinfectants can all effectively reduce bacterial load in DUWLs.Compared with other disinfectants,Sanosil has advantage of inhibiting bacterial growth after disinfection.

Mycological contamination in dental unit waterlines in Istanbul, Turkey

Studies on dental units (DUs) are conducted either for the prevention or the reduction of the density of bacterial contamination in dental unit waterlines (DUWLs). However, the existence of fungi in the these systems requires more attention. During dental treatment, direct contact with water contaminated with fungi such as Candida, Aspergillus, or inhalation of aerosols from high-speed drill may cause various respiratory infections, such as asthma, allergies, and wounds on mucose membranes, especially on immunocompromised patients and dentists. The aims of this study are to investigate the number and colonization of fungi in DUWLs in the city of Istanbul, Turkey. Water samples were collected from air-water syringes, high-speed drills, and inlet waters from 41 DUs. The aerobic mesophilic fungi count in highspeed drills was higher than inlet waters and air-water syringes. Non-sporulating fungi were found in 7 DUs. The isolated fungi were identified as Penicillium waksmanii, Cladosporium spp., Penicillium spp., Candida famata, Cryptococcus laurentii, Candida guilliermondii, Penicillium verrucosum, Aspergillus pseudoglaucus, Penicillium decumbens, and Acremonium sp. Some of these fungal genera are known as opportunistic pathogens that led to respiratory diseases such as allergic rhinits. This study shows the importance of regular control of mycological contamination on water at DUs.

Time-effect Relationship of Flushing Dental Handpieces to Prevent Suction-induced Contamination / 中华医院感染学杂志

OBJECTIVE To observe the effect of flushing dental handpieces to prevent suction-induced contamination and to lower the bacterial level in dental unit waterlines,and then to analyze the time-effect relationship of flushing.METHODS Twelve BienAir handpieces(group A) and 12 W&H TA-96 handpieces(group B) were employed in this study.The water samples from each handpiece′s outlet were immediately taken once when operations of de-caries,cavity-preparing and dental-drilling had been completed,and then taken once per 0.5 min while the handpieces were being flushed by running without work for 4 min.The bacterial colony formation of these water samples was counted on R2A agar plates.Colony forming units vs flushing time were then compared.RESULTS Alike in groups A and B,water bacterial levels were lowered the most significantly while flushing the handpieces for 0.5 min.BienAir or W&H TA-96 handpieces still showed decreased levels of water bacteria when being flushed for 3 or 2.5 min respectively.Afterwards,the flushing effect reached to a platform,that was,more flushing time didn′t bring the bacterial level down further.CONCLUSIONS Flushing handpieces by running without work can significantly reduce the level of bacterial contamination in the waterlines.Different types of handpieces may have different flushing time at which the most effect is reached.