[Study on the effect of alginate impression spray disinfection process on model accuracy].

PURPOSE: To investigate the effect of a new cleaning and disinfection process of oral impressions on the accuracy of alginate dental impression. METHODS: Sixteen young volunteers were selected to make alginate oral impression (2 times for each upper and lower jaw) and oral scandata acquisition (1 time for each upper and lower jaw) to obtain STL data. The 2 pairs of alginate impressions of each subject were numbered group 1, group 2, inwhich group 1 was not sterilized and the oral impression film in group 2 was treated with the method and steps of new oral impression cleaning and disinfection. All the oral impressions of the subjects were perfused with plaster models in the same standard way and demoulded. The obtained plaster models were examined and scanned after appropriate trimming and grinding. The plaster model data obtained from each group of each patient after warehouse scanning were compared with the orally scanned model data for alignment analysis, and root mean square(RMS) was used as a parameter to evaluate the deviation between the test model and the standard model. The chromatograms of the deviations were saved for visualization and analysis to observe the differences in model accuracy from several dimensions. Statistical analysis was performed with SPSS 23.0 software package. RESULTS: The differences in RMS of model accuracy of maxillary dental series of alginate impressions were statistically significant, in which the RMS of the group disinfecting the maxillary oral impression film with a new oral impression cleaning and disinfection process was significantly higher than that of the nonsterilized group (P=0.006), while the difference between model accuracy RMS of the mandibular disinfection group and non-disinfection group was not statistically significant(P=0.874). CONCLUSIONS: The new technical specifications for cleaning and disinfection of dental impressions recommended by the Chinese Stomatological Association have certain effects on the accuracy of dental impressions made of alginate material,and the details in its process should be further improved.

Current overview for chemical disinfection of dental impressions and models based on its criteria of usage: A microbiological study.

Objectives: The aims of this study were to compare the efficacy of two proven chemical disinfectants, glutaraldehyde and povidone iodine on dental impression and models by determining the reduction in the microbial load, and to compare changes in the physical properties of the models after adding the disinfectants. Materials and Methods: Irreversible hydrocolloid upper impressions of 90 patients were made and divided into 3 groups of 30 samples each; Group A--Control group; Impressions were run under clean tap water before pouring the model. Group B--2% Glutaraldehyde sprayed on the impression and left in situ for 10 min before pouring the model. Group C -10 ml of (5%) povidone iodine incorporated into the gypsum before pouring the model. Models from all three groups were subjected to microbiological assessment at three different time intervals, T0--24 h, T1--1 month and T2--3 months of storage by comparing the colony forming units (CFUs) of bacteria and fungi. The compressive strength of 5 models from each group was also analyzed in Newton's/mm2. Results: 2% Glutaraldehyde proved more effective than povidone iodine after 24 h of storage (T1), however at the end of 1 month (T1) and 3 months (T2) the Povidone group showed the maximum disinfection. Both the disinfectants caused a reduction in the compressive strength of the model with the povidone iodine group showing the maximum reduction. Conclusion: Although povidone iodine was the most effective disinfectant after 3 months, it showed a significant reduction in the compressive strength and caused discoloration of the model. 2% Glutaraldehyde proved to be the choice of disinfectant with minimal adverse effects.

Waterline Disinfectants Reduce Dental Bioaerosols: A Multitracer Validation.

Oral microbes are dispersed during dental treatment and reduction methods have been proposed, but dental unit waterline (DUWL) disinfectants have received little attention; specifically, the effect on viruses has not been studied. This study aims to 1) investigate the effect of DUWL disinfectants on viral dispersion in dental bioaerosols and 2) establish a dual-tracer system using live bacteriophage and fluorescein supported by optical particle measurement. Bacteriophage MS2 was used as a viral tracer and fluorescein as a fluorescent tracer. Validation experiments were conducted to exclude interference of one tracer with the other or of DUWL disinfectants on detection methods. Simulated "saliva" containing the tracers was infused into the mouth of a dental mannequin during 10-min dental procedures with an air turbine handpiece (n = 3 replicates). Aerosols and droplets were sampled in an enclosed dental operatory using air samplers and settlement onto sterile filter papers. Bacteriophage was quantified using plaque assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Fluorescein was quantified fluorometrically. The effect of DUWL disinfectants on total aerosol concentration was assessed in separate experiments using an optical particle counter. DUWL disinfectants reduced bacteriophage viability, and interference between tracers was not observed. In simulated clinical procedures, the disinfectant ICX reduced bacteriophage detection substantially (P < 0.001; 2-way analysis of variance). MS2 RNA was detected in all experimental samples but not negative controls. Samples positive on RT-qPCR but not plaque assays may indicate that virions at distant sites are nonviable. Fluorescein tracer showed good agreement with the bacteriophage tracer. DUWL disinfectants designed for continuous presence in irrigants reduce the dispersion of viable virus in dental bioaerosols during simulated procedures. Their use may therefore be important for routine infection control and as a mitigation factor during infectious disease outbreaks. Future studies should explore this using a range of viruses and other microbes.

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.

Effect of Different Denture Base Cleansers on Surface Roughness of Heat Polymerised Acrylic Materials with Different Curing Process / Efecto de diferentes limpiadores para dentaduras en la rugosidad de la superficie de acrílicos polimerizados por calor con diferentes procesos de curado

Abstract Avoiding biofilm formation on dentures is associated with maintaining the surface properties of acrylic-based dentures. The aim of the study is to investigate the effects of two different cleaning agents (Corega and Klorhex 0.2% chlorhexidine gluconate) on surface roughness of the denture regarding efficacy of curing procedures. A total of sixty disc-shaped specimens were prepared with two different methods as long and short curing processes. The specimens were divided into subgroups according to the immersion solutions (distilled water, Corega tablet group and Klorhex 0.2% chlorhexidine gluconate group) (n=10). The samples were kept in a solution for 8 hours per day during a month. The average Ra1 (before exposure to the cleanser agent) and Ra2 (after exposure to the cleanser agent) of each sample was measured. A two- way ANOVA and post hoc Tukey test was used for statistical analysis. The solutions significantly increased the Ra values in both acrylic groups (p0.05). The long-term curing time is highly effective in decreasing the surface roughness of the acrylic base material.

Resumen Evitar la formación de biopelículas en las prótesis dentales se asocia con el mantenimiento de las propiedades de la superficie de las prótesis de base acrílica. El objetivo del estudio es investigar los efectos de dos agentes de limpieza diferentes (Corega y Klorhex 0,2% gluconato de clorhexidina) en la rugosidad de la superficie de la dentadura postiza en cuanto a la eficacia de los procedimientos de curado. Se prepararon un total de sesenta muestras en forma de disco con dos métodos diferentes como procesos de curado largos y cortos. Las muestras se dividieron en subgrupos según las soluciones de inmersión (agua destilada, grupo de pastillas Corega y grupo de gluconato de clorhexidina al 0,2%) (n=10). Las muestras se mantuvieron en una solución durante 8 horas al día durante un mes. Se midió el promedio de Ra1 (antes de la exposición al agente de limpieza) y Ra2 (después de la exposición al agente de limpieza) de cada muestra. Para el análisis estadístico se utilizó un ANOVA de dos vías y una prueba post hoc de Tukey. Las soluciones aumentaron significativamente los valores de Ra en ambos grupos acrílicos (p 0,05). El tiempo de curado a largo plazo es muy eficaz para disminuir la rugosidad de la superficie del material de base acrílica.

Decontamination of Gutta-percha Cones employed in Endodontics.

The gutta-percha cones used in endodontic treatment are produced in aseptic conditions and their composition includes zinc oxide, which is responsible for antibacterial activity. However, there is the possibility of microbial contamination by manipulation, aerosol or during storage. Although several chemical agents have been tested for their decontamination, there is no consensus on the best disinfection protocol to be used. The aim of this study was to evaluate the decontamination of gutta-percha cones contaminated with the bacteria Enterococcus faecalis, by using chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) at different concentrations for short exposure times. For this purpose, gutta-percha cones (size 40) were selected at random from a sealed box and immersed for 1 min in a microbial suspension. Then they were immersed in specific Petri dishes for different groups containing: CHX 2%, NaClO 1% or NaClO 2.5% for 30 s or 1 min, and subsequently placed in tubes containing BHI broth. After incubating the tubes for 48 h, it was observed that 1% and 2.5% NaClO and 2% CHX were effective for decontaminating the cones at those exposure time intervals. Microbial growth was detected in one of the replicates of the group with CHX applied for 30 s. To prevent the possibility of failures at this stage, the exposure time of gutta-percha cones to the decontaminating agent should not be reduced.

Os cones de guta-percha utilizados no tratamento endodôntico são produzidos em condições assépticas e possuem óxido de zinco em sua composição, responsável pela atividade antibac-teriana. No entanto, existe a possibilidade de contaminação microbiana por manipulação, aerossol ou seu armazenamento. Embora vários agentes químicos já tenham sido testados para sua descontaminação, não há consenso sobre o melhor protocolo de desinfecção a ser usado. Nosso objetivo foi avaliar a descontaminação de cones de guta-percha contaminados com a bactéria Enterococcus faecalis, utilizando digluconato de clorexidina (CHX) e hipoclorito de sódio (NaClO) em diferentes concentrações e tempos de exposição curtos. Para esse fim, 40 cones de guta-percha foram selecionados aleatoriamente, de uma caixa selada e imersos por 1 min em uma suspensão microbiana. Em seguida, foram imersos em placas de Petri específicas para diferentes grupos contendo: CHX 2%, NaClO 1% ou 2,5%, nos tempos de exposição de 30s e 1min e subseqüentemente imersos em tubos contendo caldo BHI. Após incubação dos tubos por 48 h, observou-se que NaClO 1% e 2,5% e CHX 2% foram eficazes para a descontaminação dos cones nesses intervalos de tempo de exposição. Em uma das réplicas do grupo com CHX aplicado por 30s foi detectado crescimento microbiano. O tempo de exposição dos cones de guta-percha ao agente de descontaminação não deve ser reduzido para evitar a possibilidade de falhas nesse estágio.

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.

Decontamination of Gutta-percha Cones employed in Endodontics / Descontaminação de cones de guta-percha empregados em endodontia

ABSTRACT The guttapercha cones used in endodontic treatment are produced in aseptic conditions and their composition includes zinc oxide, which is responsible for antibacterial activity. However, there is the possibility of microbial contamination by manipulation, aerosol or during storage. Although several chemical agents have been tested for their decontamination, there is no consensus on the best disinfection protocol to be used. The aim of this study was to evaluate the decontamination of guttapercha cones contaminated with the bacteria Enterococcus faecalis, by using chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) at different concentrations for short exposure times. For this purpose, guttapercha cones (size 40) were selected at random from a sealed box and immersed for 1 min in a microbial suspension. Then they were immersed in specific Petri dishes for different groups containing: CHX 2%, NaClO 1% or NaClO 2.5% for 30 s or 1 min, and subsequently placed in tubes containing BHI broth. After incubating the tubes for 48 h, it was observed that 1% and 2.5% NaClO and 2% CHX were effective for decontaminating the cones at those exposure time intervals. Microbial growth was detected in one of the replicates of the group with CHX applied for 30 s. To prevent the possibility of failures at this stage, the exposure time of guttapercha cones to the decontaminating agent should not be reduced.

RESUMO Os cones de gutapercha utilizados no tratamento endodôntico são produzidos em condições assépticas e possuem óxido de zinco em sua composição, responsável pela atividade antibac te riana. No entanto, existe a possibilidade de contaminação microbiana por manipulação, aerossol ou seu armazenamento. Embora vários agentes químicos já tenham sido testados para sua descontaminação, não há consenso sobre o melhor proto colo de desinfecção a ser usado. Nosso objetivo foi avaliar a descontaminação de cones de gutapercha contaminados com a bactéria Enterococcus faecalis, utilizando digluconato de clorexidina (CHX) e hipoclorito de sódio (NaClO) em diferentes concentrações e tempos de exposição curtos. Para esse fim, 40 cones de gutapercha foram selecionados aleatoriamente, de uma caixa selada e imersos por 1 min em uma suspensão microbiana. Em seguida, foram imersos em placas de Petri específicas para diferentes grupos contendo: CHX 2%, NaClO 1% ou 2,5%, nos tempos de exposição de 30s e 1min e subseqüentemente imersos em tubos contendo caldo BHI. Após incubação dos tubos por 48 h, observouse que NaClO 1% e 2,5% e CHX 2% foram eficazes para a descontaminação dos cones nesses intervalos de tempo de exposição. Em uma das réplicas do grupo com CHX aplicado por 30s foi detectado crescimento microbiano. O tempo de exposição dos cones de gutapercha ao agente de desconta minação não deve ser reduzido para evitar a possibilidade de falhas nesse estágio.

Efficacy of BRS® and Alpron®/Bilpron® Disinfectants for Dental Unit Waterlines: A Six-Year Study.

Biofilms in dental unit waterlines (DUWL) are a potentially significant source of contamination posing a significant health risk as these may come into contact with patients and dental staff during treatment. The aim of this study was to evaluate the microbiological quality of DUWL water treated by Biofilm-Removing-System® (BRS®) and Alpron®/Bilpron® disinfectant solutions for six years in a French university hospital. The microbiological quality of water supplied by 68 dental units-initially shock treated with BRS®, then continuously treated by Alpron® with sterile water during working days and Bilpron® during inactivity period, and combined with purging every morning and after each patient-was assessed biannually during six years for total culturable aerobic bacteria at 22 °C and 36 °C, Legionella sp., Pseudomonas aeruginosa, and total coliforms. A total of 628 samples were analyzed, 99.8% were compliant with extended microbiological levels, and we never detected pathogen bacteria like Legionella sp. and P. aeruginosa. Only one sample (0.2%) was noncompliant with the level of total culturable aerobic bacteria at 36 °C, which exceeded 140 colony forming units per mL. The protocol implemented in our university hospital gives excellent results and enables control of the microbiological quality of DUWL water in the long term.

[Aerosol transmission risk and comprehensive prevention and control strategy in dental treatments].

Splatter, droplet and aerosol, which potentially cause disease via contact and droplets transmission, may be produced during dental treatments. Through the risk model analysis of airborne diseases, it is clarified that the key points of preventing aerosol transmission are infection source management, increasing ventilation, reducing exposure time and correct use of protective masks. In order to reduce the aerosol pollution, it is necessary to strengthen the management of water and air piping systems and the control of splashing. Air and surface disinfection and enhanced personnel protection may reduce the risk. Based on the analysis of infection chain, this article elaborates the role of standard and additional precautions for cutting off the disease transmission chain. Systematic, comprehensive and evidence-based prevention and control measures should become our concerns.

A simplified in vitro model for investigation of the antimicrobial efficacy of various antiseptic agents to prevent peri-implantitis.

The biofilm formation by oral bacteria on the implant surface is one of the most remarkable factors of peri-implant infections, which may eventually lead to bone resorption and loss of the dental implant. Therefore, the elimination of biofilm is an essential step for the successful therapy of implant-related infections. In this work we created a basic in vitro model to evaluate the antibacterial effect of three widely used antiseptics.Commercially pure (CP4) titanium sample discs with sand blasted, acid etched, and polished surface were used. The discs were incubated with mono-cultures of Streptococcus mitis and Streptococcus salivarius. The adhered bacterial biofilms were treated with different antiseptics: chlorhexidine-digluconate (CHX), povidone-iodine (PI), and chlorine dioxide (CD) for 5 min and the control discs with ultrapure water. The antibacterial effect of the antiseptics was tested by colorimetric assay.According to the results, the PI and the CD were statistically the most effective in the elimination of the two test bacteria on both titanium surfaces after 5 min treatment time. The CD showed significant effect only against S. salivarius.Based on our results we conclude that PI and CD may be promising antibacterial agents to disinfecting the peri-implant site in the dental practice.

Importance of disinfection time and procedure with different alginate impression products to reduce dimensional instability.

AIMS: The aim of this study was to determine the best approach to reduce the unfavorable change in the three different dimensions of impressions using disinfection durations of 15 and 30 min; three different disinfection procedures; and alginate impression products as research factors. MATERIALS AND METHODS: CA37, impressional, and cream alginate impressions were used; distortion in the AB, AC, and BC dimensions of impressions using disinfection durations of 15 and 30 min was studied; and no disinfection (ND), conventional disinfection (CD), and sonicator-activated disinfection (SAD) procedures were measured. RESULTS: Regarding AB dimension, the impressional has best performance when CD was applied for both 15 and 30 min. When SAD was applied for 15 min, impressional and cream alginates provide best performance. When CD was applied for 15 min, CA37 and impressional alginates provide best performance. Although ND-applied CA37 alginate after 30 min provides best performance, because of many outlier values, its implication may not be considered as meaningful. Regarding AC dimension, cream alginate has best performance when CD was applied for 15 min. The AC distances in all the alginates are considerably different from the base model after 30 min. Regarding BC dimension, only the CA37 alginate has the best performance when ND was applied for 15 min. All the alginates are considerably different from that of the base model after 30 min. CONCLUSION: Preference of 15-min disinfection can provide favorable results to obtain all impressions with minimally distorted dimensions. CD is an adequate procedure. The studied SAD needs to be developed further. All alginates are comparably successful to obtain impressions with desired distortion degrees.

The effect of disinfectants on the accuracy, quality and surface structure of impression materials and gypsum casts: A comparative study using light microscopy, scanning electron microscopy and micro computed tomography.

The aim of this study was to compare the effect of several commercially available disinfectants on the accuracy of various types of impression materials and their compatibility with gypsum including surface quality and structure evaluation. Four alginate and three elastomeric impression materials in combination with disinfectants Aseptoprint Liquid, Zeta 7 solution, Silosept and Dentaclean Form were tested. The dimensional changes, detail reproduction, the compatibility with gypsum and surface/subsurface morphology were evaluated using light microscopy, scanning electron microscopy and micro computed tomography. Two alginate materials disinfected in Dentaclean Form exhibited the most significant differences (p<0.0001). The loss of detail on some alginate impressions in combination with this disinfectant including deterioration and change of morphology of gypsum surfaces was observed. Porosity in subsurface area and exposed large particles were detected. It was confirmed that the desired properties of impressions may be negatively affected in combination with some disinfectants.

Micrographic evaluation of different widia compositions of orthodontic pliers submitted to peracetic acid and intensive use / Avaliação micrográfica de diferentes composições de widia de alicates ortodônticos submetido ao ácido peracético e uso intensivo

Introduction: The sterilization and disinfection procedures should be adapted to the chemical profile of the metal alloys present in the instruments. Objective: This study aimed to perform a micrographic assessment on the surface characteristics of the widia of orthodontic pliers with two alloy compositions subjected to the action of 0.2% peracetic acid and intensive use. Material and method: Twenty distal cutting pliers were divided into two groups (n=10) according to widia composition (%wt): W1- 85% to 87% of tungsten carbide (TC) and other components in the proportion of 13% to 15% and W2 - 87.5% to 88.5% of tungsten carbide and 11.5% to 12.5% for other components. All the pliers were assessed in a stereoscopic magnifying glass (32x) after three treatments: before use (T0); after cutting 100 segments of rectangular stainless-steel wires - intensive use (T1); and after 100 sterilization cycles in 0.2% peracetic acid and intensive use (T2). The cutting sites of all pliers were standardized. Widia regions were defined by line "A" representing T1 and line "B" representing T2. A frequency distribution table and Fisher's exact test (α=0.05) was performed. We assessed two widia from each composition and treatment in SEM and energy-dispersive X-ray spectroscopy (EDS/SEM). Result: The results showed that W1 pliers presented significantly fewer defects after the sterilization cycles with peracetic acid and intensive use than W2 pliers (p=0.0198). There were no differences between both pliers after intensive use (p=1.000). Conclusion: The SEM images and EDS analyses showed changes in widia surfaces after the different treatments. Widia composition affected the resistance of the orthodontic pliers after sterilization cycles with 0.2% peracetic acid and intensive use.

Introdução: Os procedimentos de esterilização e desinfecção devem ser adaptados ao perfil químico das ligas metálicas presentes nos instrumentos. Objetivo: O objetivo do estudo foi realizar uma avaliação micrográfica das características da superfície da widia de alicates ortodônticos com duas composições de ligas submetidas à ação de ácido peracético a 0,2% e uso intensivo. Material e método: Vinte alicates de corte distal foram divididos em dois grupos (n=10), de acordo com a composição widia (% em peso): W1- 85% a 87% de carboneto de tungstênio e outros componentes na proporção de 13% a 15% e W2 - 87,5% a 88,5% de carboneto de tungstênio e 11,5% a 12,5% para outros componentes. Os alicates foram avaliados em uma lupa estereoscópica (32x) após três tratamentos: antes do uso (T0); após corte de 100 segmentos de fios retangulares de aço inoxidável- uso intensivo (T1); após 100 ciclos de esterilização em ácido peracético a 0,2% e uso intensivo (T2). Os locais de corte dos alicates foram definidos pela linha "A" representando T1 e pela linha "B" representando T2. Foi realizada uma tabela de distribuição de frequências e o teste exato de Fisher (α=0,05). As widias foram avaliadas em MEV e Espectroscopia de Energia Dispersiva. Resultado: Os alicates W1 apresentaram defeitos significativamente menores após os ciclos de esterilização com ácido peracético e uso intensivo do que os alicates W2 (p=0,0198). Não houve diferenças entre os dois alicates após uso intensivo (p=1.000). Conclusão: As imagens de MEV/EDS mostraram alterações nas superfícies widia após os diferentes tratamentos. A composição widia afetou a resistência do alicate ortodôntico após ciclos de esterilização com ácido peracético a 0,2% e uso intensivo.

Do ozonated water and boric acid affect the bond strength to dentin in different adhesive systems?

AIM: The aim of this in vitro study was to compare the effects of the application of three different cavity disinfecting agents to dentin on the micro-shear bond strength (µ-SBS) of one self-etch and two universal adhesive systems. MATERIALS AND METHODS: In total, 120 caries-free human permanent molar teeth were used in this study. Mid-coronal dentin surfaces were revealed by cutting occlusal enamel and a standard smear layer was obtained by using 600-800-1200 grid silicon carbide abrasive papers. Specimens were randomly assigned to four groups according to the disinfectant used: Group 1: Control (no disinfectant); Group 2: 2% chlorhexidine based (Consepsis); Group 3: 10 ppm ozonated water (TeknO3zone); Group 4: 5% boric acid (Handmade). Each group was divided into three subgroups according to the type of adhesive (Clearfil SE Bond, OptiBond XTR, and Tokuyama Universal). Specimens were bonded using either Clearfil SE Bond, OptiBond XTR or Tokuyama Universal, which were employed according to the manufacturer's instructions. Resin composite microcylinders were bonded using Tygon® tubes for µ-SBS testing. After specimens were stored for 24 h, at 37°C in distilled water, µ-SBS test was measured with a universal test machine (LF Plus, Lloyd, Instrument). µ-SBS results were analyzed by one-way analysis of variance (ANOVA) and Tukey's tests. RESULTS: When the mean microshear bond strength values of the control group were compared, the difference between the subgroups was not significant (P < 0.05). When the mean microshear bond strength values of the chx, ozonated water, and boric acid were compared, the difference between Clearfil SE Bond and Tokuyama Universal was significant (P < 0.05) and the difference between the other groups was not significant (P > 0.05). CONCLUSION: Ozonated water and boric acid may be as an alternative to other materials used as cavity disinfectants.

Dental Unit Waterlines: A Survey of Practices in Eastern France.

Water is essential during dental care. Physical and chemical techniques should be used to maintain a good water quality with respect to bacteria, and to ensure the safety of exposed patients and dental staff. The aim of this survey was to assess the modalities used by dental practitioners in Eastern France to maintain the water quality of their dental unit waterlines (DUWLs). A questionnaire about water quality maintenance practices was sent to 870 dental offices in 2016. The questionnaires were completed by 153 dental offices, covering about 223 dental care units. The majority of units were fed by mains water (91.0%), which is generally unfiltered (71.3%). One-third (33.6%) of the units had an independent water bottle reservoir. Flushing, a basic physical technique to improve the quality of units' outflow water, was practiced in 65.4% of dental offices. Concerning the chemical treatment of water, it was used for 62.1% of the units. An analysis of the microbiological quality of the DUWL water was only carried out in 2.6% of the offices. In conclusion, providing better training to dental staff seems necessary to improve their practices and to generalize procedures that improve the microbiological quality of the water used.

The Clinical Effectiveness of Calcium Hydroxide in Root Canal Disinfection of Primary Teeth: A Meta-Analysis.

BACKGROUND The aim of this research was to systematically analyze the effectiveness of calcium hydroxide compared to formocresol (FC) and camphor phenol (CP) in root canal disinfection of primary teeth. MATERIAL AND METHODS The meta-analysis was based on the participants, interventions, control, outcome (PICO) study design principle and 16 randomized-controlled clinical trials published from January 2000 to August 2018. The data heterogeneity of each study was assessed by the Q-test. The odds ratio and 95% confidence interval (CI) were calculated based on the heterogeneity results by Revman software. RESULTS Sixteen randomized-controlled clinical trials of 3047 primary teeth were included in this meta-analysis. There were significant differences of clinical effectiveness between calcium hydroxide and FC in root canal disinfection of primary teeth (OR=3.37; 95% CI range: 2.54-4.48, P<0.01) and endodontic inter-appointment emergencies (EIAE) after disinfection for 7 days (OR=0.26; 95% CI range: 0.16-0.42, P<0.01). However, there was no statistical difference of EIAE, after disinfection of primary teeth for 48 hours, between calcium hydroxide and FC (OR=0.62; 95% CI range: 0.34-1.11, P=0.11). There were significant differences of clinical effectiveness between the calcium hydroxide and CP in root canal disinfection of primary teeth (OR=5.50; 95% CI range: 3.36-8.98, P<0.01). CONCLUSIONS This meta-analysis indicated that the effectiveness of calcium hydroxide as root canal disinfectant in primary teeth was more effective than that of FC and CP.

Effectiveness of the ozone application in two-visit indirect pulp therapy of permanent molars with deep carious lesion: a randomized clinical trial.

OBJECTIVES: The aim of this randomized, three-arm parallel, single-blinded clinical trial was to evaluate the clinical and microbiological effectiveness of the ozone application in two-visit indirect pulp therapy. MATERIALS AND METHODS: One hundred five lower first molar teeth with deep caries lesion were included and randomly assigned three groups to apply the two-visit indirect pulp therapy. Treatment procedure was applied without any disinfectant (control), with 60-s 2% chlorhexidine digluconate (CHX) or 60-s ozone application. In four different stages (after initial excavation, ozone/CHX application before the temporary restoration, 4 months later immediately after removing temporary restoration, and final excavation), dentin humidity, consistency, and color properties were recorded to evaluate the clinical characteristics of the tissue, and standard dentin samples were collected for the microbiological analysis of mutans streptococci, lactobacilli, and the total number of colony-forming units. The data were analyzed by using Mann-Whitney U test for multiple comparisons. RESULTS: The remaining dentin became harder, drier, and darker after 4 months in all groups. However, CHX and ozone application were statistically better than the control group (p < 0.05). There was a gradual decrease in the total number of microorganisms in all groups. While cavity disinfectant applications were improved the antibacterial efficacy (control, 79.11%; CHX, 98.39%; ozone, 93.33%), CHX application exhibited a greater significant reduction than both groups (p = 0.000). CONCLUSION: The two-visit indirect pulp therapy yielded successful results for all study groups. However, CHX would be conveniently preferable due to improving the treatment success. CLINICAL RELEVANCE: The two-visit indirect pulp therapy applied with cavity disinfectant is a proper alternative treatment procedure in deep carious lesions, instead of conventional technique.

Ultrasonic Irrigant Activation during Root Canal Treatment: A Systematic Review.

INTRODUCTION: The aim of this study was to systematically review the evidence on the cleaning and disinfection of root canals and the healing of apical periodontitis when ultrasonic irrigant activation is applied during primary root canal treatment of mature permanent teeth compared with syringe irrigation. METHODS: An electronic search was conducted of the Cochrane Library, Embase, LILACS, PubMed, SciELO, and Scopus databases using both free-text key words and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and textbooks. The retrieved studies were screened by 2 reviewers according to predefined criteria. The included studies were critically appraised, and the extracted data were arranged in tables. RESULTS: The electronic and hand search retrieved 1966 titles. Three clinical studies and 45 in vitro studies were included in this review. Ultrasonic activation did not improve the healing rate of apical periodontitis compared with syringe irrigation after primary root canal treatment of teeth with a single root canal. Conflicting results were reported by the in vitro microbiological studies. Ultrasonic activation was more effective than syringe irrigation in the removal of pulp tissue remnants and hard tissue debris based on both clinical and in vitro studies. Ultrasonic activation groups were possibly favored in 13 studies, whereas syringe irrigation groups may have been favored in 3 studies. CONCLUSIONS: The level of the available evidence was low, so no strong clinical recommendations could be formulated. Future studies should focus on the antimicrobial effect and healing of apical periodontitis in teeth with multiple root canals.

Tracking of the degradation process of chlorhexidine digluconate and ethylenediaminetetraacetic acid in the presence of hyper-pure chlorine dioxide in endodontic disinfection.

Accurate knowledge of the safety of the combined use of hyper-pure chlorine dioxide (ClO2, Solumium) with different endodontic agents is not known. The objective was to investigate the possible interactions between hyper-pure ClO2 and Chlorhexidine digluconate (CHX) as well as hyper-pure ClO2 and ethylenediaminetetraacetic acid (EDTA) in vitro. High-performance liquid chromatography (HPLC) was used to analyse the reaction between ClO2 and CHX for studying the possible increase of para-chloroaniline (PCA). Nuclear magnetic resonance (NMR) method was applied to investigate if the oxidising property of ClO2 inactivates EDTA. CHX itself may contain PCA; however, its amount did not increase after the mixing up with ClO2. While ClO2 did not oxidise PCA, on the other hand, it oxidised EDTA into numerous degradation products, but this reaction was slow. Hyper-pure ClO2 of excellent antimicrobial properties should be considered as a safe alternative endodontic disinfectant agent in combinations or as a final rinse. The lack of chemical interaction between ClO2 and CHX confirms their safe application in combination.