Penetration of sodium hypochlorite into root canal dentine: effect of surfactants, gel form and passive ultrasonic irrigation.

AIM: To assess the penetration of sodium hypochlorite (NaOCl) gel or NaOCl solutions with surfactants, and the effect of passive ultrasonic irrigation (PUI) on penetration into dentinal tubules. METHODOLOGY: Bovine incisor root canals were instrumented, the roots sectioned and the dentine blocks obtained were stained with crystal violet. Dentine blocks (n = 10 per group) were exposed to 3% NaOCl gel or 3% NaOCl solution for 10 and 20 min. Other dentine blocks (n = 10 per group) were exposed to Chlor-Extra (6% NaOCl + surfactant), 6% NaOCl, 2.5% NaOCl with 0.2% cetrimide and 2.5% NaOCl for 10 and 20 min. The penetration depth of irrigants into dentinal tubules was measured in micrometres by viewing the bleached crystal violet under a stereomicroscope. Additionally, bovine incisor root canals, instrumented and stained with crystal violet, were distributed into two groups (n = 10) and irrigated with 2.5% NaOCl with PUI or conventional syringe irrigation (CSI). The penetration depth of irrigants into dentinal tubules was assessed 3 and 7 mm from the apex. Statistical analysis was performed by ANOVA and Tukey tests (α = 0.05). RESULTS: There was significantly greater penetration of 3% NaOCl solution into dentinal tubules compared with the gel form (P < 0.05). There was no difference (P > 0.05) between 6% NaOCl and Chlor-Extra, and between 2.5% NaOCl and 2.5% NaOCl + cetrimide. PUI significantly increased the penetration depth of NaOCl into dentinal tubules when compared with CSI (P < 0.05). CONCLUSIONS: In extracted bovine incisors, NaOCl gel penetrated less into dentinal tubules than NaOCl solution. The addition of surfactants did not increase the penetration depth. The use of PUI significantly increased NaOCl penetration into dentinal tubules.

Sodium hypochlorite penetration into dentinal tubules after manual dynamic agitation and ultrasonic activation: a histochemical evaluation.

The aim of this study was to compare the effects of Manual Dynamic Agitation and Passive Ultrasonic Irrigation on sodium hypochlorite (NaOCl) penetration into dentinal tubules using its bleaching ability. Thirty-four single-rooted teeth with round-shaped root canals were distributed in two homogeneous groups and one control group, characterized by different NaOCl activation systems: Manual Dynamic Agitation and Passive Ultrasonic Irrigation. After instrumentation, all root canals were stained with 10% copper sulphate solution followed by 1% rubeanic acid alcohol solution under vacuum. Final irrigation was performed with 5 mL of 5.25% NaOCl solution for 1 min and activated with Manual Dynamic Agitation or Passive Ultrasonic Irrigation for another 1 min depending on the treatment group. The teeth were transversely sectioned at the middle portion of the apical, middle, and coronal thirds and observed under light microscope. NaOCl solution penetration was evaluated by measuring the percentage of bleached circumference of the root canal relative to the stained circumference, bleached areas, mean, and maximum penetration depth. No differences in the evaluated parameters were observed between groups (p > 0.05). Within groups, an increase of values was recorded from apical to coronal direction as for percentage of staining, percentage of bleaching and bleached area. NaOCl penetration into dentinal tubules did not significantly vary among the three levels. No significant differences in penetration of sodium hypochlorite into dentinal tubules when activated by means of Manual Dynamic Agitation or Passive Ultrasonic Irrigation were observed in the apical, middle, and coronal thirds of teeth with single straight round root canals.

Sodium hypochlorite solution penetration into human dentine: a histochemical evaluation.

AIM: The aim of this study was to evaluate ex vivo the penetration depth of sodium hypochlorite solutions, with and without surfactants, into human dentine using a histochemical stain and the bleaching ability of NaOCl. METHODOLOGY: Extracted maxillary central incisors were decoronated and their root canals were shaped to a size 30, .07 taper. Dentinal tubules were stained with 10% copper sulphate solution followed by a 1% rubeanic acid alcohol solution under vacuum. Specimens were irrigated with 5 mL of Niclor 5 (5.25% NaOCl solution) or 5 mL of Hypoclean (5.25% NaOCl solution + surfactants) according to the corresponding treatment group, for 2 min. A transverse section was obtained in the middle portion of the apical, middle and coronal thirds of each tooth. Under microscopic examination, irrigant penetration was evaluated by measuring the following: the bleached circumference of the root canal with respect to the stained circumference; bleached areas, mean and maximum penetration depth. For statistical analysis, Pearson's chi-squared test and one-way anova were used. RESULTS: Only 30% of dentine tubules in the apical portions were stained; therefore, these were excluded from further comparisons. In the middle and coronal thirds, the average bleached circumference of the root canal was 80-99% of the stained circumference and the bleached area was 73757-135107 µm2 . The average penetration depth ranged from 39 to 62 µm and maximum penetration from 74 to 131 µm. For all reported results, no differences within and between groups were observed (P = 1). CONCLUSION: No differences in penetration of irrigants with and without surfactants into dentinal tubules were observed in the middle and coronal thirds of incisor teeth.

Penetration of hypochlorites with lowered surface tension into dentine tubules.

BACKGROUND: The purpose of the present study was to assess the effect of concentration and temperature of sodium hypochlorite (NaOCl) with added surfactants and time of exposure on its penetration into human dentine. METHODS: Seventy-five extracted permanent maxillary anterior teeth with single canals were shaped by using ProTaper SX hand-operated instruments. Then teeth were sectioned perpendicular to their long axis. The crowns and apical thirds of all the teeth were removed. The remaining roots were processed into 4-mm-long blocks and stained overnight in crystal violet. One hundred fifty stained blocks were further split into halves and treated by six NaOCl-based solutions from different brands: three solutions added with surfactants (Hypoclean, H6, Chlor-Xtra) and their regular counterparts (5.25%, 6%, <%6NaOCl). The dentine blocks were exposed to the solutions for 2, 5, and 20 minutes at 20° C, 37° C, and 45° C, respectively. The depth of penetration of NaOCl was determined by bleaching of the stain and measured by light microscopy at magnifications of 20x and 40x. Statistical analysis was made by using two way ANOVA and by comparing groups two by two with t-test. RESULTS: The shortest penetration (130.80±1.92µm) was measured after incubation with 5.25%NaOCl for 2 minutes at 20° C; the highest penetration (375.40±3.05µm) was obtained with Chlor-Xtra for 20 minutes at 45° C. Temperature and exposure time had a significant direct relationship with penetration of sodium hypochlorites with lowered surface tension into dentinal tubules. CONCLUSIONS: The exposure time and temperature of sodium hypochlorite as well as the addition of surfactants may influence the penetration depth of irrigants into dentinal tubules.

Application of 17% EDTA Enhances Diffusion of (45)Ca-labeled OH(-) and Ca(2+) in Primary Tooth Root Canal.

Proper cleaning of the root canal is key to the success of endodontic treatment as it allows more effective diffusion of medication throughout the dentinal tubules. The aim of this in vitro study was to investigate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA) in enhancing diffusion of hydroxyl (OH(-)) and calcium ions (Ca(2+)) throughout the root canal in primary teeth. The canals of 25 primary tooth roots were cleaned with endodontic files and 1% sodium hypochlorite. Three groups (G) were then established: GI, in which final irrigation was performed with 1% sodium hypochlorite; GII, in which 17% EDTA was used; and GIII, in which no irrigation was performed. The roots canals in GI and GII were filled with a calcium hydroxide-based paste labeled with the radioisotope calcium-45. Diffusion of OH(-) was detected with pH strips and Ca(2+) analyzed by measuring radioactivity in counts per min. Group II differed statistically from the other groups in diffusion of OH(-) at 24 hr (p<0.05), but no significant difference among groups was found at the day 7 evaluation; GII also differed statistically from the other groups in diffusion of Ca(2+) at 24 hr (p<0.05). These results suggest that application of 17% EDTA in primary tooth enhances diffusion of OH(-) and Ca(2+).

Eliminación de Enterococcus faecalis por medio del uso de hipoclorito de sodio, clorhexidina y MTAD en conductos radiculares / Elimination of Enterococcus faecalis using sodium hypochlorite, chorhexidine and MTAD in root canals

Objetivos: Comparar la efectividad de diferentes soluciones irrigadoras en la eliminación de cepas de Enterococcus faecalis en pacientes con patología periapical crónica, mediante pruebas microbiológicas. Métodos: Se evaluaron 21 dientes con diagnóstico de periodontitis apicales crónicas no supurativas de pacientes que asistieron a consulta en las clínicas odontológicas de la Universidad de Cartagena, previa firma y aprobación del consentimiento informado para participar en el estudio. Los sujetos de estudio se asignaron aleatoriamente en tres grupos usando las siguientes sustancias irrigantes: hipoclorito de sodio al 5%, clorhexidina al 2% e hipoclorito de sodio 2,5% con irrigación final de MTAD. Se identificaron microorganismos por medio de la prueba Reacción en Cadena de la Polimerasa (PCR) y se cuantificaron las unidades formadoras de colonias de Enterococcus faecalisantes y después de ser utilizadas las sustancias irrigadoras. Análisis estadístico: Se realizó el test de Kruskal wallis. Resultados: La investigación demostró que todas las sustancias fueron efectivas en la eliminación de E. faecalisen pacientes con periodontitis apicales crónicas no supurativas. El hipoclorito de sodio al 5% (p= 0,018), hipoclorito de sodio y MTAD (p= 0,021) y clorhexidina al 2% (p= 0,028) fueron igual de efectivas. Conclusiones: El hipoclorito de sodio al 5%, clorhexidina al 2%, hipoclorito de sodio y MTAD pueden ser utilizadas en pacientes con periodontitis apical crónica no supurativa por ser efectivas en la eliminación de E. faecalis (AU)

Objectives: To compare the effectiveness of different irrigating solutions in eliminating of Enterococcus faecalisin patients with chronic periapical pathology by applying microbiological tests. Methods: Twenty one teeth with chronic apical periodontitis of non suppurative diagnosis of patients that attended the dental clinics of the University of Cartagena were evaluated after the patients signed the consent form to participate in the study. The study subjects were randomized into three groups using the following irrigating substances: Sodium hypochlorite at 5%, chlorhexidine 2% and sodium hypochlorite and MTAD. Microorganisms were identified through the Chain Reaction (PCR) and quantified the colony forming units before and after Enteroccocus faecalis be used irrigating substances for cleansing. Statistical analysis: We performed the Kruskal Wallis test. Results: The research showed that all substances were effective in eliminating E. faecalis in patients with chronic apical periodontitis non suppurative. Sodium hypochlorite 5% (p= 0,018), sodium hypochlorite and MTAD (p= 0,021) and chlorhexidine 2% (p= 0,028) were equally effective. Conclusions: Sodium hypochlorite 5% chlorhexidine 2% and sodium hypochlorite and MTAD can be used in patients with chronic apical periodontitis non suppurative after being proven effective in eliminating E. faecalis (AU)

Biofilm en endodoncia y su tratamiento / Biofilm in Endodontics and its treatment

El biofilm es la forma más habitual que utilizan las bacterias para crecer y sobrevivir en la naturaleza. Hoy en día se considera que bajo ciertas condiciones ambientales, todos los microorganismos son capaces de formar biofilms. Por ello y por todos los problemas que causan tanto en el entorno médico como odontológico causando infecciones crónicas difíciles de erradicar con los tratamientos convencionales conocidos, el interés por su estudio ha aumentado en las dos últimas decadas. El objetivo de esta revisión es actualizar los conocimientos de tratamiento para el control y eliminación del biofilm en la terapia endodóntica (AU)

Biofilm is the most common form in nature used by bacteria to grow and survive. Nowadays it is considered that under certain environmental conditions, all organisms are able to create biofilms. Due to this ability and to the potential problem both in Medicine and Dentistry related to chronic infections difficult to eradicate with conventional treatments, the studies about biofilm have increased over the past two decades.I The aim of this review is to update the knowledge of treatment for the control and elimination of the biofilm in endodontic therapy (AU)

Interferometric microscopy study of the surface roughness of Portland cement under the action of different irrigants

OBJECTIVES: Some investigations suggested common Portland cement (PC) as a substitute material for MTA for endodontic use; both MTA and PC have a similar composition. The aim of this study was to determine the surface roughness of common PC before and after the exposition to different endodontic irrigating solutions: 10% and 20% citric acid, 17% ethylenediaminetetraacetic (EDTA) and 5% sodium hypochlorite. Study design: Fifty PC samples in the form of cubes were prepared. PC was mixed with distilled water (powder/liquid ratio 3:1 by weight). The samples were immersed for one minute in 10% and 20% citric acid, 17% EDTA and 5% sodium hypochlorite. After gold coating, PC samples were examined using the New View 100 Zygo interferometric microscope. It was used to examine and register the surface roughness and the profile of two different areas of each sample. Analysis of variance (ANOVA) was carried out, and as the requirements were not met, use was made of the Kruskal-Wallis test for analysis of the results obtained, followed by contrasts using Tukey's contrast tests. RESULTS: Sodium hypochlorite at a concentration of 5% significantly reduced the surface roughness of PC, while 20% citric acid significantly increased surface roughness. The other evaluated citric acid concentration (10%) slightly increased the surface roughness of PC, though statistical significance was not reached. EDTA at a concentration of 17% failed to modify PC surface roughness. Irrigation with 5% sodium hypochlorite and 20% citric acid lowered and raised the roughness values, respectively. CONCLUSIONS: The surface texture of PC is modified as the result of treatment with different irrigating solutions commonly used in endodontics, depending on their chemical composition and concentration

Comparison of irrigant penetration up to working length and into simulated lateral canals using various irrigating techniques.

AIM: To evaluate the effect of an apical negative pressure system, a passive ultrasonic irrigation system and a combination of both apical negative pressure and passive ultrasonic irrigation on the penetration of the irrigating contrast solution (ICS) up to working length and into simulated lateral canals. METHODOLOGY: The root canals of 64 single-rooted teeth were instrumented using the ProTaper rotary system. In each sample, three simulated lateral canals were created at 2, 4 and 6 mm levels from the root apex using a 06-size C+ file (Dentsply Maillefer, Ballaigues, Switzerland). Samples were randomly assigned into 4 experimental groups (n = 16): group I - conventional needle irrigation, group II - passive ultrasonic irrigation, group III - apical negative irrigation system and group IV - combination of passive ultrasonic irrigation and apical negative pressure irrigation system. To examine irrigating solution penetration, Indian ink was mixed with 5.25% NaOCl and delivered into the root canals. Samples were then assessed by direct observation of the images taken using Canon EOS rebel T3. The depth of penetration of ICS up to the working length and into the simulated lateral canals was analysed using chi-squared tests. RESULTS: The combination (ANP and PUI) and ANP group had significantly deeper ICS penetration up to the working length (P < 0.001). The combination (ANP and PUI) and the PUI group exhibited significantly greater ICS penetration into lateral canals at the 6 mm level (P < 0.001). At the 4 and 2 mm levels, the combination of ANP and PUI had significantly greater ICS penetration into the lateral canals than the other groups (P < 0.001). CONCLUSIONS: The combination of ANP and PUI was the only group able to achieve irrigating contrast solution penetration both up to the working length and into lateral canals.

The effect of surface tension reduction on the clinical performance of sodium hypochlorite in endodontics.

Sodium hypochlorite (NaOCl) is recommended as an endodontic irrigant in view of its broad antimicrobial and tissue dissolution capacities. To enhance its penetration into inaccessible areas of root canals and to improve its overall effect, the addition of surface-active agents has been suggested. The aim of this investigation was to review the effect of the reduction of the surface tension on the performance of NaOCl in endodontics. A search was performed in the Medline electronic database (articles published up to 28 July 2012, in English) with the search terms and combinations as follows: 'sodium hypochlorite AND surface tension or interfacial force or interfacial tension or surface-active agent or amphiphilic agent or surface active agent or surfactant or tenside or detergent'. The purpose of this search was to identify publications that compared NaOCl alone and NaOCl modified with the addition of a surface-active agent in endodontics. A hand search of articles published online ('in-press' and 'early view'), and appearing in the reference list of the articles included, was further performed, using the same search criteria as the electronic search. The search identified 302 publications, of which 11 fulfilled the inclusion/exclusion criteria of the review. The evidence available suggests that surface-active agents improve the penetration of NaOCl in the main canal and have no effect on its pulp tissue dissolution ability. There are, however, insufficient data to enable a sound conclusion to be drawn regarding the effect of modifying NaOCl's surface tension on lubrication, antimicrobial and smear layer or debris removal abilities.

Estudio in vitro de la eficacia del hipoclorito de sodio y la clorhexidina contra el enterococcus faecalis / Antimicrobial effects of sodium hipochlorite and clorhexidine against Enterococcus faecalis. A in vitro study

Objetivo. El propósito principal de esta investigación in vitro es comparar el efecto antimicrobiano de la clorhexidina (CHX) y del hipoclorito de sodio (NaCIO) a diferentes concentraciones contra el E. faecalis, analizando a la vez distintos tiempos de acción de cada una de las sustancias de estudio. Material y método. Las sustancias de estudio han sido: NaCIO caliente al 2,5%, NaCIO al 5,25%, CHX líquida al 2% NaCIO caliente al 2,5% junto al CHX líquida al 2%, NaCIO al 5,25% junto a CHX líquida al 2% y suero salino como grupo control Los tiempos analizados: 15", 30", 1', 3', 5', 10', 15', 30' y 1 hora. Para la identificación bacteriana hemos empleado dos métodos diferentes: la tinción diferencial de Gram y la diferencias estadísticamente significativas valores de p<=0,05. Resultados. Mayor eficacia en la erradicación de bacterias de la CHX líquida 2% frente al resto de irrigantes, hallando diferencias estadísticamente significativas con todos, excepto con NaCIO 5,25% + CHX líquida 2%. Conclusiones. La combinación del NaCIO y la CHX no supera la acción antimicrobiana de la CHX aislada (AU)

Objetive. To investigate in vitro the antimicrobial activity of sodium hypochlorite (NaCIO) and clorhexidine (CHX) in different concentrations against Enterococcus faecalis, compared with the efficacy of the combination of the same irrigating substances. Material and methods. The substances tested wre: 2,5% warm NaCIO 5,25% NaCIO, 2% liquid CHX 2,5 warm NaCIO with 2% liquid CHX, 5,25% NaCIO with 2% liquid CHX. Sterile saline was used as control Analyzed times: 15", 30", 1', 3', 5', 10', 15', 30' and 1 hour. For the bacterial identification we have used two different methods: the agar diffusion test and a biochemical identification kit (API 20 Strep, Biomereux, Madrid). Statistical analysis was conducted with the Student's t test. Differences were considered statistically significant when p<=0.05. Results. Inferential analysis revealed a statistically significant difference in the reduction of bacteria between CHX liquid 2% and the rest of irrigants, except with NaCIO 5,25% + liquid CHX 2%. Conclusions. The association of NaCIO and CHX did not improve the antimicrobial activity of CHX alone (AU)

Capacidad de disolución de tejido pulpar vital del hipoclorito de sodio al 5, 25% y clorhexidina al 2% / Dissolution capacity of pulp vital tissue by sodium hypochlorite 5, 25% and 2% chlorhexidine

Objetivo. Comprobar la capacidad de disolución de tejido pulpar vital de hipoclorito de sodio al 5.25% y Clorhexidina al 2% post instrumentación rotatoria. Material y método. Se analizaron treinta y dos primeros premolares superiores con vitalidad pulpar que se obtuvieron post exodoncia. Fueron agrupados en: grupo 1, irrigación con NaOCI 5,25%; grupo, 2, irrigación con CHX 2%; grupo 3 o control irrigación con suero fisiológico, seguidamente las piezas dentarias fueron instrumentadas con sistema de limas rotatorias, irrigadas con las soluciones descritas y posteriormente muestras histológicas fueron teñidas y finalmente observadas en microscopio óptico. Resultados. Mostraron que no hubo diferencia estadística significativa tanto en los grupos irrigados por NaOCI 5.25% y CHX 2% debido a que fueron encontrados tejido pulpar residual en todos los grupos. Los tercios coronarios fueron mayormente desprovisto de tejido pulpar que en los tercios apicales. La anatomía accesoria no fue desprovista de tejido pulpar. Conclusión. Aunque la CHX no tenga capacidad de disolver tejido pulpar y los resultados de este estudio no hayan demostrado diferencia estadística significativa en relación al NaOCI este resultado no se debe al efecto disolutorio de las soluciones irrigadoras sino a que el NaOCI no tuve suficiente tiempo de contacto con tejido pulpar (AU)

Aim. Of this study was to test the ability of vital pulp tissue dissolution of 5.25% sodium hypochlorite and 2% chlorhexidine after rotary instrumentation system. Material and methods. Thrity-two freshly extracted premolar teeth, with pulps vital at the time of extraction were assigned in groups. Group 1, 5.25% NaOCI irrigation, group 2, 2% CHX irrigtation, group 3 with distilled water irrigation as control. After to teeth were instrumented with rotary files system, irrigated with the solutions described and decalcified. Each root was divided in thirds and transverse histological sections were perfomed at four levels, then histological samples were stained and observed in microscope optical. Results. No statistically significant differences were found in both groups irrigated by 5.25% NaOCI and CHX 2% residual pulp tissue were found in all groups. Coronal parts were more frequently devoid of pulp tissue than the apical. The isthmus had residual pulp tissue less frequently in the NaOCI groups. Accessory anatomy was unaffected regardless of irrigant. Conclusions. Although CHX has no ability to dissolve pulp tissue and the results of this study were not statistically significantly compared to NaOCI. This results this is not due to the dissolving effect of irrigating solutions but that NaOCI did not have enough time contact with pulp tissue (AU)

Wetting ability of an acetone/based etch&rinse adhesive after NaOCl-treatment

Objectives: to evaluate the effect of sodium hypochlorite (NaOCl) treatment on surface dentin roughness (Ra) and contact angle (CA) when using Prime&Bond NT adhesive (PB NT). Study Design: Extracted human third molars were sectioned to expose flat, superficial and deep dentin surfaces. CA and Ra were measured (1) before and (2) after 35% H3PO4 etching, and (3) H3PO4 etching + 5% NaOCl treated for 2 minutes before the application of PB NT. CA was measured by the Axisymmetric Drop Shape Analysis Technique using distilled and deionized water and PB NT. Roughness was evaluated with a profilometer, twelve radial measurements were performed in each treatment surface. Data were analyzed with two-way ANOVA and Newman-Keuls multiple comparison test procedures. Results: CA values decreased after acid etching and even more after NaOCl treatment on deep dentin when water was tested. With resin, there were not differences on CA results after H3PO4 neither after NaOCl treatment, in both dentin surfaces. Etching and NaOCl treatment resulted in surface roughness increase. Conclusions: In spite of the higher roughness after NaOCl treatment on superficial and deep dentin, the use of 5% NaOCl for 2 min after dentin demineralization when PB NT was employed did not improved the wettability of dentin, probably due to nanofiller content and/or hydrogen-bonding interactions with residues of the organic matrix on collagen-depleted dentin (AU)

In vitro antimicrobial activity of Sodium hypochlorite, Chlorhexidinegluconate and Octenidine Dihydrochloride in elimination of microorganisms within dentinal tubules of primary and permanent teeth

The aim of this study was to evaluate the effectiveness of different irrigation solutions at different time intervals for the elimination of E.faecalis and C.albicans penetrated into the dentine tubules of primary and permanent teeth in vitro.The 4mm primary and permanent teeth sections were sterilized and contaminated with a mixture of E.faecalis and C.albicans strains. After the apllication of different irrigation solutions (..) (AU)

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Efficacy of different concentrations of sodium hypochlorite andchlorhexidine in disinfection of contaminated Resilon cones

Objectives: The aim of this study was to evaluate the effectiveness of different concentrations of Chlorhexidine(CHX) and sodium hypochlorite (NaOCl) in disinfecting contaminated Resilon cones within one minute. Study design: Fifty Resilon cones were divided into seven experimental groups and three control groups of 5cones each. The cones of experimental groups were contaminated with Entrococcus faecalis and subsequently disinfected with different concentrations of NaOCl or CHX. The cones were then transferred into glass tubes containing thioglycollate media and incubated for 7 days. The tubes were examined for turbidity every 24 hours, and if bacterial growth occurred, samples were plated, incubated, gram stained and observed under microscope to confirm E. faecalis growth. Negative, positive, and washing control groups were also used. Results: All the positive and washing control showed profound E. faecalis growth. All the cones disinfected with CHX showed bacterial growth; however, no E. faecalis growth occurred in any samples disinfected with NaOCl. Conclusion: Sodium hypochlorite, at concentrations of 0.5 to 5.25%, is an effective agent for disinfection of contaminated Resilon cones within one minute; however, chlorhexidine is unable to disinfect Resilon cones during one-minute exposure (AU)

Penetration into dentin of sodium hypochlorite associated with acid solutions.

OBJECTIVE: The objective of this study was to evaluate the penetration of 2.5% NaOCl associated with 17.0% EDTA, 1.0% citric acid, and 1.0% peracetic acid into dentin tubules. STUDY DESIGN: The roots of 44 bovine incisors were cross-sectioned and 5-mm-long fragments were produced from their middle thirds. The specimens were instrumented with ProTaper hand files, stained in crystal violet, then sectioned mesiodistally. The buccal fragments were divided into 4 groups (n = 9) and subjected to 2 consecutive 10-minute immersion periods in one of the following acid solutions combined with 2.5% NaOCl: 17.0% EDTA (group 1), 1.0% citric acid (group 2), and 1.0% peracetic acid (group 3). Nine fragments were immersed in 2.5% NaOCl (group 4). The analysis of the penetration of NaOCl solutions into dentin was performed by measuring the depth of crystal violet stain that was bleached using a steromicroscope under ×50 magnification. Statistical comparisons were carried out by Kruskal-Wallis and Dunn's tests at the 5% significance level. RESULTS: Group 1 showed less penetration into dentin than group 4 (P < .05). No statistically significant differences were observed among groups 2, 3, and 4 (P > .05). CONCLUSIONS: Association of NaOCl with acid solutions did not increase its penetration depth into root dentin.

Residual antibacterial activity of a new modified sodium hypochlorite-basedendodontic irrigation solution

Objective: In this in vitro study the antibacterial substantivity of a new sodium hypochlorite-based root canal irrigant(Hypoclean) in bovine root dentin was investigated.Study Design: Ninety dentin tubes prepared from bovine incisor teeth were used. After contamination for 14days with Enterococcus faecalis, the specimens were divided into five groups as follows: Hypoclean; Tetraclean;5.25% sodium hypochlorite (NaOCl); infected dentin tubes (positive control); and sterile dentin tubes (negativecontrol). Dentin chips were collected with round burs into tryptic soy broth and after culturing, the number ofcolony-forming units (CFU) was counted.Results: The number of CFU was minimum in the first cultures in all experimental groups, and the results obtainedwere significantly different from each other at any time period (P < 0.05). At all five experimental periods,the Tetraclean group showed the most effective antibacterial action (P < 0.05). Regular 5.25% NaOCl groupshowed the worst result at all periods. Hypoclean group demonstrated no bacterial growth after treatment. In eachgroup, the number of CFU increased significantly by time-lapse (P < 0.05).Conclusion: The residual antibacterial activity of Tetraclean was significantly greater than Hypoclean and 5.25%NaOCl (AU)

Biofilm. Un Nuevo concepto de infección en Endodoncia / Biofilm. A new infection concept in endodintics

Distintos estudios concluyen que el porcentaje de éxito del tratamiento de conductos en dientes necróticos es menor que en dientes vitales. Hoy día, se postula que la verdadera causa de fracaso de muchos tratamientos de conductos aparentemente correctos es la entidad infecciosa conocida como biofilm. Además, se ha mostrado como un tipo de infección doble. Por un lado, conocer el papel del biofilm en Endodoncia: morfología, metabolismo, formación, evolución y localización. Por otro, actualizar los métodos que propone la Endodoncia para controlarlo y eliminarlo, poniendo especial atención EN la técnica de irrigación. Elegida por muchos autores como la clave para su tratamiento (AU)

Different studies have concluded that the success rate of root canal treatment in necreotic teeth is lower than in vita l teeth. Nowadays, the real cause of failure in many root canal treatment that have apparently been correctly carried out is considered to be the infectious matter know as biofilm. Elimination form the canal of this type of infection has proved to be very difficult and has become one of the great challenges in modern endodontics. The aim of this review article is twofold: firstly, to understand the role of bifilm in endodontics, with respect to its morphology, metabolism, formation, evolution and localization, and, secondly to update endodontic procedures for controlling and eliminating it, paying particular attention to the technique of irrigation which is the preferred key to treatment of many authors (AU)

Reaction rate of NaOCl in contact with bovine dentine: effect of activation, exposure time, concentration and pH.

AIM: To determine the influence of activation method (ultrasound or laser), concentration, pH and exposure time on the reaction rate (RR) of NaOCl when in contact with dentinal walls. METHODOLOGY: The walls from standardized root canals in bovine incisors were exposed to a standardized volume of sodium hypochlorite (NaOCl) with different concentrations (2% and 10%), pH (5 and 12) and exposure times (1 and 4min). Two irrigation protocols were tested: passive ultrasonic irrigation or laser activated irrigation with no activation as the control. The activation interval lasted 1min followed by a rest interval of 3 min with no activation. The RR was determined by measuring the iodine concentration using an iodine/thiosulfate titration method. RESULTS: Exposure time, concentration and activation method influenced the reaction rate of NaOCl whereas pH did not. CONCLUSIONS: Activation is a strong modulator of the reaction rate of NaOCl. During the rest interval of 3min, the consumption of available chlorine increased significantly. This effect seems to be more pronounced after irrigant activation by laser. pH did not affect the reaction rate of 2% NaOCl.

Limpieza de las paredes del conducto usando una combinaciónde hipoclorito de sodio 2, 5% - ácido cítrico 10% y clorhexidina 2% - ácido citrico 10% / Clenalness of the root canal walls using a combination of 2, 5% sodium hypoclorte – 10% citric acid and 2% chlorhexidine – 10% citric acid

Objetivo. El propósito de este estudio fue comparar el grado de limpieza de lasparedes del conducto radicular utilizando como irrigantes la combinación de hipoclorito de sodio 2,5% - ácido cítrico 10% y clorhexidina 2% ácitdo cítrico 10%. Material y métodos: Se emplearon raíces de 35 premolares, unirradiculares de conducos rectos recientemente extraídos. L amismas fueron instrumentadas e irigadas con ls soluciones citadas, secciondas longitudinalmente y observadas al MEB a nivel cervial, medio y apical. Resultados: Los resultados indicaron limpieza de las paredes del conducto radicular con el uso de ambas cobinaciones,siendo en e terci medio, estadísticamente más efectiva la obtenida con a asociación hipoclori de sodio 2,5% - ácido cítrico 10% (p= 0,00<0,05). Conclusioes: La asociacion d ehipoclorito de sodio 2,5% - ácido cítirico 10% demostró mayor apacidad para remover la capa residual que la asociación de clorexidina 2%- ácido citrico 10% (AU)

Objective: In this study the cleanliness of the root canal walls was copared, using as irrigators the combinations of 2,5% sodium hypochlorite – 10% citric acid, and 2% chrohexidene – 10% citric acid. Material and methods: 35 single- rooted human premolars, recently extracted wereused. The same roots were instrumented and irigated with the combinatios mentioned above , then roots were sectione and observed with Scanning Electron Microscopic in cervical, middle and apical levels. Reslts: The results showed cleanliness o the root canal walls with the use of both combiations, being statistcaly more significantin the third middle, the one obtained with the combination of 2,5% sodium hypochlorite –10% citric acid (p=0 0<0,05). Conclussions: The association of 2,5% sodium hypochloite 10% citic acid was more efficiente than the combination of 2% chorhexidine- 10% citric acid (AU)