The effects of environment and time intervals on the dimensional stability of three indigenously produced irreversible hydrocolloids.

Aim: Several new irreversible hydrocolloid formulations have recently become available with claims of an improved dimensional stability by the manufacturers. The aim of this study was to evaluate the accuracy of casts made from alginate impression materials poured immediately and after specific storage periods. Methods and Materials: Three alginates were tested Zelgan (Dental Products of India), DMC Algitex (Dental manufacturing & marketing Company) and A1 Alginate (occlusion products of India). A special stainless steel die representing a crown preparation was used to obtain impressions. These impressions were poured at different time intervals i.e immediately after a lapse of 5 minutes, 15 minutes, 30 minutes & 1 hour. Impressions were stored in a three different environments i.e. Air, water & 100% humidity. The casts were made & data were analyzed. Results: The dimensional stability of the alginate impressions was both material & time dependent. Conclusion: The dimensional stability of the alginate impressions is influenced by the selected materials and the storage time. An atmosphere of 100% humidity appears to be best storage medium. Clinical Significance: Alginate impressions should generally be poured immediately . Longer the period of storage more significant dimensional changes were observed.

Microbiological assessment of the effectiveness of chlorhexidine mouthrinse before taking impressions of the oral cavity / Avaliação microbiológica da eficácia do bochecho de clorexidina prévio à moldagem da cavidade bucal

PURPOSE: The aim of this study is to assess the reduction of microbial load that adhered to irreversible hydrocolloid impressions obtained after rinsing with 0.12% and 0.2% chlorhexidine solutions. METHODS: The study consisted of 24 participants (48 dental arch impressions) equally divided into two groups: Group 1 (0.12% chlorhexidine) and Group 2 (0.2% chlorhexidine). The impressions were taken using Hydrogun® irreversible hydrocolloid before (control) and after (experimental) a single 10 mL mouthrinse of chlorhexidine for 1 minute. Each impression was placed in a sterile beaker containing 250 ml of saline. The microbiological analysis of the storage solution was carried out using BHI Agar culture medium. The plates were incubated for 24 hours, followed by a CFU (Colony Forming Units) count. The data were analyzed using the Wilcoxon's t test. RESULTS: There was a reduction in the degree of contamination of the impressions after rinsing with the antimicrobial mouth rinses at both concentrations when compared with the control group. There was a statistically significant difference when the effectiveness of the two concentrations used was compared. CONCLUSION: Therefore, using a chlorhexidine rinse prior to obtaining irreversible hydrocolloid impressions reduces contamination and is more efficient at the 0.2% concentration.

OBJETIVO: O objetivo deste estudo é avaliar a redução da carga microbiana aderida nos moldes de hidrocolóide irreversível obtidos após bochecho com clorexidina nas concentrações 0,12% e 0,2%. METODOLOGIA: O estudo incluiu 24 participantes (48 moldes de arcadas dentárias) divididos igualmente em dois grupos: Grupo 1 ( clorexidina 0,12%) e Grupo 2 (clorexidina 0,2%). As arcadas foram moldadas com hidrocolóide irreversível Hydrogun® antes (controle) e após (experimental) bochecho único com 10 mL de clorexidina nas concentrações específicas de cada grupo durante 1 minuto. Cada molde foi acomodado em bécker estéril contendo 250 mL de soro fisiológico. A partir dessa solução, realizou-se análise microbiológica em meio de cultura BHI Ágar. As placas foram submetidas a um período de incubação de 24 h oras, seguida de contagem das UFC (Unidades Formadoras de Colônias). Os dados foram submetidos à análise estatística aplicando o teste t de Wilcoxon. RESULTADOS: Observou-se redução do grau de contaminação dos moldes obtidos após bochecho com o antimicrobiano nas duas concentrações, em relação ao grupo controle e, também, diferença estatística significativa quando comparadas a eficácia das duas concentrações utilizadas. CONCLUSÃO: O bochecho de clorexidina prévio à obtenção de moldes de hidrocolóide irreversível reduz a contaminação e com melhor eficácia na concentração 0,2%.

Efficacy of various spray disinfectants on irreversible hydrocolloid impression materials: An in vitro study.

Background: Most of the materials (casts, impressions, etc.) that are sent to the dental laboratories show the presence of numerous pathogenic microorganisms. All the spray disinfectants are not equally effective against these microorganisms. Aims and Objectives: The aim was to compare the effectiveness of different spray disinfectants on irreversible hydrocolloid impressions and to find out the most effective dilution, contact time, and effect against each microorganism studied. Materials and Methods: The effects of four spray disinfectants, 5.25% sodium hypochlorite, 0.525% sodium hypochlorite, 1:213 (1 part in 213 parts of water) povidone iodine, and 2% glutaraldehyde along with control (distilled water) on irreversible hydrocolloid impressions contaminated with Staphylococcus aureus, Bacillus subtilis and Streptococcus viridans were studied. Results: Sodium hypochlorite, 5.25%, showed 1-min exposure time which was able to effect a 4log10 reduction in bacterial counts against S. aureus and S. viridans followed by 0.525% sodium hypochlorite and 2% glutaraldehyde for 10 min. None were able to effect a 4 log10 reduction against B. subtilis. Conclusion: Sodium hypochlorite with a concentration of 5.25% was the most effective disinfectant and required the shortest contact time (1 min). Not all ADA-approved concentrations of surface disinfectants work equally well on irreversible hydrocolloid impression materials.

Effect of inmersion desinfection with 0, 5 percent sodium hypochlorite and 2 percent glutaraldehyde on alginate and silicone: microbiology and SEM study / Efecto de la desinfección en inmersión con 0, 5 por ciento de hipoclorito sódico y glutaraldehído al 2 por ciento sobre alginato y silicona: estudio de la microbiología y SEM

The disinfection of dental impression materials has become an essential topic of universal concern, as it may be the first instance of microbial contamination during dental care. The purpose of this study is twofold: To determine the effectiveness of disinfection with 0.5 percent sodium hypochlorite and 2 percent glutaraldehyde solutions in irreversible hydrocolloid (alginate) and silicone impressions and to analyze the effect of disinfection on surface quality with a scanning electronic microscope. Atotal of 32 impressions (16 made of irreversible hydrocolloid and 16 made of silicone) were taken from maxillary dentate patients. Samples of 1cm2 (80 , irreversible hydrocolloid, 80 silicone) were obtained and distributed in ten groups: alginate in no disinfectant (control group 1, AL), alginate in 0.5 percent sodium hypochlorite (NaOCl) for 5 (AH5) and 10 minutes (AH10), alginate in 2 percent glutaraldehyde for 5 (AG5) and 10 minutes (AG10), silicone in no disinfectant (control group 2), silicone in 0.5 percent NaOCl for5 (SH5) and 10 minutes (SH10), and silicone in 2 percent glutaraldehyde for 5 (SG5) and 10 minutes (SG10). Each sample was divided into two segments (one for the microbiological and one for the SEM study). Microbiological samples were planted on blood agar, Mac Conkey agar, and Sabouraud agar, and identification was made by Gram´s stain. The samples were then processed by an SEM. Immersion in the 5 percent NaOCl and 2 percent glutaraldehyde for 10 minutes completely eliminated bacteria in the impressions, compared with the control group (P=0.000004). Immersion in 0.5 percent NaOCl and 2 percent glutaraldehyde for 5 and 10 minutes significantly inhibited bacterial growth in both the irreversible hydrocolloid and silicone impressions compared with control group (P<0.05). However, in the SEM study, immersion in both disinfectant solutions for 5 and 10 minutes did not significantly affect the surface quality of the irreversible hydrocolloid...

La desinfección de los materiales de impresión dental se ha convertido en un tema esencial, ya que puede ser el primer caso de contaminación microbiana durante la atención dental. El propósito de este estudio es doble: determinar la eficacia de la desinfección con hipoclorito sódico al 0,5 por ciento y 2 por ciento de glutaraldehído en soluciones de hidrocoloide irreversible (alginato) y las impresiones de silicona, para analizar el efecto de la desinfección en la calidad de la superficie con un microscopio electrónico de barrido. Un total de 32 impresiones (16 hechas de hidrocoloides irreversibles y 16 de silicona) superiores de pacientes dentados fueron estudiadas. Las muestras de 1cm2 (80, hidrocoloide irreversible, el 80 de silicona) fueron obtenidas y distribuidas en diez grupos: alginato sin desinfectante (grupo de control1, AL), alginato en el 0,5 por ciento de hipoclorito sódico (NaOCl) durante 5 (AH5) y 10 minutos (AH10), alginato en glutaraldehído al 2 por ciento durante 5 (GA5) y 10 minutos (AG10), silicona sin desinfectante (grupo de control 2), silicona en 0,5 por ciento de NaOCldurante 5 (SH5) y 10 minutos (SH10) y, en glutaraldehído al 2 por ciento durante 5 (SG5) y 10 minutos (SG10). Cada muestra se dividió en dos segmentos (uno para los análisis microbiológicos y uno para el estudio SEM). Las muestras microbiológicasse sembraron en agar sangre, agar MacConkey y agar Sabouraud, y la identificación se realizó por tinción de Gram. Las muestras fueron procesadas por un SEM. La inmersión en 5 por ciento NaOCl y 2 por ciento de glutaraldehído durante 10 minutos eliminó completamente las bacterias de las impresiones, en comparación con el grupo control (P = 0,000004). La inmersión en 0,5 por ciento de NaOCl y glutaraldehído al 2 por ciento durante 5 y 10 minutos, inhibió el crecimiento de bacterias, tanto en el hidrocoloide irreversible e impresiones de silicona en comparación con el grupo control (P <0,05). Sin embargo, en el estudio SEM...

Disinfection of irreversible hydrocolloid impressions with sodium hypochlorite steam: assessment of antimicrobial efficacy / Desinfecção de moldes de hidrocolóide irreversível com vapor de hipoclorito de sódio: avaliação da eficácia antimicrobiana

Purpose: To evaluate the antimicrobial effectiveness of 2.5% and 5.25% sodium hypochlorite steam to disinfect an irreversible hydrocolloid impressions in Humidifier and Nebulizer Boxes. Methods: The study used a total of 80 quadrant impressions of patients, divided into 4 experimental groups of 20 samples each, with respective controls. The impressions were placed in an atmosphere of sodium hypochlorite with 100% relative humidity for 10 min. After disinfection, each impression was immersed in saline solution that was ultrasonically vibrated. Microbiological analysis of the solution was carried out by counting colonies grown in BHI-agar culture medium after 24 hours in an incubator at 37ºC. The data were analyzed using Wilcoxon's t test. Results: In all groups, it was found that the mean number of colonies in control groups was higher then in the experimental groups (P<0.0001). There was a significant difference between using the Nebulizer Box and the Humidifier Box when 2.5% sodium hypochlorite was used. At a concentration of 5.25% there was no statistical difference between the mean numbers of colonies for the two methods (P>0.01). Conclusion: Sodium hypochlorite at 5.25% can be used for disinfection in the Humidifier Box and Nebulizer Box methods. However, at a 2.5% concentration it is only effective in the Nebulizer box method.

Objetivo: avaliar a eficácia antimicrobiana do vapor de hipoclorito de sódio 2,5% e 5,25% na desinfecção de moldes de hidrocolóide irreversível em Caixa Umidificadora e Caixa Nebulizadora. Metodologia: Utilizaram-se 80 moldes de hemiarcos de pacientes, distribuídos em 4 grupos experimentais de 20 amostras cada, com respectivos controles. Os moldes permaneceram 10 min em atmosfera de hipoclorito de sódio com 100% de umidade relativa. Após desinfecção, cada molde foi imerso em soro fisiológico sob vibração ultrassônica e a análise microbiológica dessa solução foi realizada pela contagem de colônias que cresceram em meio de cultura BHI-ágar após 24h em estufa incubadora a 37ºC. Os dados foram analisados pelo teste t de Wilcoxon. Resultados: Em todos os grupos observou-se maior número médio de colônias dos grupos controles em relação aos experimentais (P<0,0001). Para 2,5% de hipoclorito de sódio houve diferença estatística significativa entre Caixa Nebulizadora e Caixa Umidificadora. A concentração 5,25% não demonstrou diferença estatística entre os números médios de colônias nos dois métodos utilizados (P>0,01). Conclusão: Hipoclorito de sódio 5,25% poderá ser utilizado para desinfecção nos métodos Caixa Umidificadora e Caixa Nebulizadora, no entanto, a concentração 2,5%, só será eficaz quando utilizada no método Caixa Nebulizadora.

Avaliação dimensional de moldes de hidrocolóide irreversível após desinfecção / Dimensional evaluation of molds of irreversible hydrocolloid after disinfection

O objetivo deste estudo foi avaliar se a desinfecção com hipoclorito de sódio afeta dimensionalmente moldes de alginato. A partir de um modelo padrão (grupo1-controle) confeccionado com 2 componentes protéticos para implante (Sistema INP, Mod.: Standard Diâmetro. 6 x 3) fixados em uma base de resina (Clássico, Indústria Brasileira), foram confeccionados 14 moldes (n=07) de hidrocolóide irreversível (tipo II, Jeltrate/Dentsply) os quais foram submetidos a duas condições experimentais: G2) enxaguados em água corrente por 15 segundos e preenchidos imediatamente com gesso especial tipo IV/Dent-Mix/Asfer; G3) enxaguados em água corrente por 15 segundos, pulverizados com uma solução de hipoclorito de sódio a 0,5% (Asfer Indústria e Comércio Ltda), acondicionado em saco plástico fechado por 10 minutos, enxaguados com água gessada e preenchidos com gesso especial. Após 1 hora, moldes e modelos foram separados. Com auxílio de um paquímetro digital (centesimal N° PA 04, MITUTOYO) um mesmo operador realizou as mensurações entre pontos distais dos componentes de todos os grupos. Os resultados foram submetidos a análise de variância Anova a 2 critérios e teste de Tukey com intervalo de confiança de 95%. Ao avaliar os resultados, podemos concluir que a prática da desinfecção por pulverização com solução de hipoclorito de sódio a 0,5% por 10 minutos não influenciou na estabilidade dimensional dos moldes de hidrocolóide irreversível.

The objective of this study is to evaluate if the disinfection with sodium hypochlorite affects alginate molds dimensionally. From a standard model (control group-1) confectioned with 2 prosthetic components for implantation (System INP, Mod.: Standard Diameter. 6 x 3) fixed in a base of resin (Classic, Brazilian Industry), 14 molds (n=07) of irreversible hydrocolloid (type II, Jeltrate/Dentsply) were confectioned, of which were submitted under 2 experimental conditions: G2) one group was rinsed in current water for 15 seconds and immediately filled with special plaster type IV Dent-Mix/Asfer; G3) the other was rinsed in current water for 15 seconds and sprayed with a solution of sodium hypochlorite 0.5% (Asfer, Industry and I deal Ltda), conditioned in a closed plastic bag for 10 minutes, rinsed in plastered water and filled with special plaster. After 1 hour, molds and models were separated. With the assistance of a digital paquimeter (centesimal Nº PA - 04, MITUTOYO) an operator carried out the measurement between the distal points of the components of all groups. The results were analyzed by Anova under 2 criteria test of Tukey with a reliable interval of 95%. When evaluating the results, we can conclude that, the practice of disinfecting by spraying with sodium hypochlorite solution of 0.5% for 10 minutes did not influence the dimensional stability of the molds of hydrocolloid irreversible.