Physicochemical Properties and Antibiofilm Activity of Tricalcium Silicate Cement and its Association with Cetrimide / Propiedades físico-químicas y actividad antibiofilm del cemento de silicato tricálcico y su asociación con cetrimida

Abstract Cetrimide (CTR) is a cationic surfactant detergent with antimicrobial and antibiofilm activity. The aim of this study was to evaluate setting time, pH, solubility and antibiofilm activity of tricalcium silicate cement (TSC) with zirconium oxide (ZrO2) and its association with 0.2 and 0.4% cetrimide. Initial and final setting times (IST and FST) were assessed based on ISO-6876. pH was evaluated at periods of 1,3,7,14 and 21 days. Solubility was analyzed by weight loss. A modified direct contact test (MDCT) on the biofilm of Enterococcus faecalis formed on bovine root dentin blocks was performed, after 6 hours of manipulation and 15 hours of contact time. The analysis was performed by UFC mL ¯¹ counting. The data were analyzed by ANOVA and Tukey's tests (α=0.05). Higher IST was observed for TSC/ZrO2+CTR in both concentrations than for TSC/ZrO2 and lower FST for TSC/ZrO2+0.4% CTR (p0.05). All materials exhibited increased mass. TSC/ZrO2+CTR 0.4% had lower mass gain than the other materials (p<0.05). The highest antibiofilm activity was observed for TSC/ZrO2+CTR in both concentrations, when compared with the positive control (p<0.05). In conclusion, CTR exhibited potential to promote greater antibiofilm activity to tricalcium silicate cement, without harming its physicochemical properties of setting time, pH and solubility.

Resumen Cetrimida (CTR) es un detergente y surfactante catiónico con actividad antimicrobiana y antibiofilm. El objetivo de este estudio fue evaluar el tiempo de fraguado, pH, solubilidad y actividad antibiofilm del cemento de silicato tricálcico (CST) con óxido de zirconio (ZrO2) y su asociación con CTR a 0.2% y 0.4%. Tiempo de fraguado inicial y final (TFI y TFF) fueron determinados con base en las normas ISO-6876. pH fue evaluado en los períodos de 1,3, 7,14 y 21 días. Solubilidad fue analizada por la pérdida de masa/peso. El test de contacto directo modificado (TCDM) fue realizado sobre biofilm de Enterococcus faecalis formado en dentina radicular bovina, después de 6 horas de manipulación de los cementos y 15 horas de contacto. El análisis fue realizado por la cuantificación de UFC mL¯¹. Los datos fueron analizados usando las pruebas de ANOVA y Tukey (α=0.05). Mayor TFI fue observado para CST/ ZrO2+CTR en las dos concentraciones que para TSC/ZrO2 y menor TFF para TSC/ ZrO2+CTR 0.4% (p0.05). Todos los materiales mostraron aumento de masa. TSC/ZrO2+CTR 0.4% tuvo menor gano de masa que los otros materiales (p<0.05). Mayor actividad antibiofilm fue observado para CST/ZrO2+CTR en las dos concentraciones, cuando comparados con el grupo control positivo (p<0.05). En conclusión, CTR demostró potencial para promover superior actividad antibiofilm al cemento de silicato tricálcico (CST), sin perjudicar sus propiedades físico-químicas de tiempo de fraguado, pH y solubilidad.

Different formulations of peracetic acid: effects on smear layer removal, dentine erosion, cytotoxicity and antibiofilm activity

Abstract Objective: To assess the effects of different peracetic acid (PAA) formulations on smear layer (SL) removal, dentine erosion, cytotoxicity, and antibiofilm activity. Methodology: SL removal and dentine erosion were assessed using 90 premolars, distributed into six groups, according to final irrigation: PAA formulations (1% Sigma, 1% Bacterend OX, 1% Arposept, and 0.09-0.15% Anioxyde), 17% ethylenediaminetetraacetic acid (EDTA), and water (control). Cytotoxicity was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red assays. Antibacterial and antibiofilm effectiveness was evaluated against Enterococcus faecalis. For cytotoxicity and antibiofilm activity assessment, the 2.5% NaOCl was also included. Results: EDTA, Sigma, and Bacterend OX removed more SL than Arposept, Anioxyde, and water (p<0.05). EDTA caused more severe dentine erosion than Sigma and Bacterend OX (p<0.05). Sigma and Bacterend OX had higher cytotoxicity than the other solutions (p<0.05). NaOCl, Bacterend OX, Sigma, and Anioxyde significantly reduced E. faecalis colony-forming units (CFU) (p<0.05). The 2.5% NaOCl solution promoted greater biofilm biomass reduction (p<0.05) than the other solutions. All PAA formulations promoted greater biomass reduction than 17% EDTA (p<0.05). Conclusions: Although Sigma and Bacterend OX had higher cytotoxicity, they had a SL removal capability similar to that of EDTA, were as effective as NaOCl against E. faecalis biofilm, and promoted less dentine erosion than EDTA. Arposept and Anioxyde failed to remove the SL, had lower cytotoxicity, and showed less bacterial activity than NaOCl.

Physicochemical properties, cytocompatibility and antibiofilm activity of a new calcium silicate sealer

Abstract The aim of this study was to evaluate the physicochemical properties, cytocompatibility and antibiofilm activity of a new calcium silicate-based endodontic sealer, Sealer Plus BC (MK Life, Brazil), in comparison with TotalFill BC Sealer (FKG Dentaire SA, Switzerland) and AH Plus (Dentsply, Germany). Setting time and flow were evaluated based on ISO 6876 standard. The pH was evaluated after different periods, and radiopacity by radiographic analysis (mmAl). Solubility (% mass loss) and volumetric change (by micro-CT) were assessed after 30 days of immersion in distilled water. Cytocompatibility was assessed by methyltetrazolium (MTT) and neutral red (NR) assays, after exposure of Saos-2 cells to the sealer extract for 24 h. An additional analysis was performed by using MTT assay after 1, 3 and 7 days of exposure of Saos-2 to the sealers 1:8 dilution extracts. Antibiofilm activity against Enterococcus faecalis and/or Candida albicans was evaluated by crystal violet assay and modified direct contact test. The physicochemical properties were analyzed using ANOVA/Tukey tests; MTT and NR data were analyzed by ANOVA and Bonferroni tests; the antimicrobial tests were analyzed by Kruskal-Wallis and Dunn tests (α=0.05). Sealer Plus BC had proper setting time, radiopacity, flow and alkalization capacity. Sealer Plus BC was significantly more soluble than AH Plus (p<0.05) and presented volumetric change similar to AH Plus and TotalFill BC (p>0.05). Sealer Plus BC presented antibiofilm activity and no cytotoxic effect. In conclusion, although Sealer Plus BC had higher solubility, this sealer showed proper physicochemical properties, cytocompatibility, and antibiofilm activity.

Resumo O objetivo deste estudo foi avaliar as propriedades físico-químicas, a citocompatibilidade e a atividade antibiofilme de um novo cimento endodôntico à base de silicato de cálcio, Sealer Plus BC (MK Life, Brasil), em comparação com TotalFill BC Sealer (FKG Dentaire SA, Suíça) e AH Plus (Dentsply, Alemanha). O tempo de presa e o escoamento foram avaliados com base nas normas ISO 6876. O pH foi avaliado após diferentes períodos, e a radiopacidade por análise radiográfica (mmAl). A solubilidade (% de perda de massa) e alteração volumétrica (por micro-CT) foram avaliadas após 30 dias de imersão em água destilada. Citocompatibilidade foi avaliada pelos ensaios metiltetrazólio (MTT) e vermelho neutro (NR), após exposição das células Saos-2 ao extrato de cimento por 24 horas. Análise adicional foi realizada através do ensaio MTT após 1, 3 e 7 dias de exposição das células Saos-2 aos extratos dos cimentos na diluição de 1:8. Atividade antibiofilme contra Enterococcus faecalis e/ou Candida albicans foi avaliada pelos ensaios cristal violeta e contato direto modificado. As propriedades físico-químicas foram analisadas utilizando os testes ANOVA e Tukey; MTT e NR foram analisados pelos testes ANOVA e Bonferroni; os ensaios antimicrobianos foram analisados pelos testes Kruskal-Wallis e Dunn (α=0.05). Sealer Plus BC apresentou tempo de presa, radiopacidade e escoamento adequados, além de capacidade de alcalinização. Sealer Plus BC foi significantemente mais solúvel que AH Plus (p<0.05) e apresentou alteração volumétrica similar à de AH Plus e TotalFill BC (p>0.05). Sealer Plus BC apresentou atividade antibiofilme, sem efeito citotóxico. Como conclusão, embora Sealer Plus BC apresente maior solubilidade, este cimento apresentou propriedades físico-químicas adequadas, citocompatibilidade e atividade antibiofilme.

Influência da agulha e fluxo de irrigação na limpeza do canal radicular e extrusão apical de irrigante: análise em micro-CT / Influence of needle and irrigation flow rate on root canal cleaning and apical extrusion of irrigant: Micro-CT analysis

Introdução: O tipo de agulha e fluxo de irrigação é importante para a limpeza adequada no terço apical do canal radicular. Objetivo: Avaliar a influência do tipo de agulha e fluxo de irrigação na limpeza do canal radicular e canais laterais simulados e na extrusão apical do irrigante. Métodos: Trinta e dois dentes de resina foram utiliza- dos. Após a instrumentação do canal radicular, foram feitos quatro canais laterais a 2 e 7 mm do ápice. Os canais radiculares foram preenchidos com solução de contraste. Os canais foram irrigados com dois tipos de agulha, 29G e 31G, com diferentes designs (abertura lateral e apical) e dois fluxos (2 ou 5 mL/min), a 1 mm aquém do comprimento de trabalho. O volume da solução de contraste nos canais principal e laterais após irrigação e a extrusão apical do irrigante (mm3 ) foi avaliado por micro-CT, em comparação com a análise inicial. Os dados em porcentagem foram analisados pelos testes ANOVA e Tukey (α=0,05). Resultados: não houve diferença entre os protocolos de irrigação para limpeza da solução de contraste. Maior volume de extrusão apical com agulha 29G com abertura apical e 5 mL/min foi observado, em comparação ao mesmo tipo de agulha e 2 mL/min (p<0,05). Conclusão: Todos os protocolos de irrigação foram associados à limpeza dos canais radiculares. Maior extrusão apical foi observada com agulha 29G ­ abertura apical com maior fluxo de irrigação (5 mL/min). Implicações clínicas: Irrigação endodôntica com agulha com abertura apical e maior fluxo da solução pode favorecer a extrusão dos irrigantes para os tecidos periapicais (AU).

Introduction: needle and irrigation flow rate are important for proper cleaning of the root canal. Aim: to evaluate the influence of type of needle and irrigation flow rate on cleaning of root canal and simulated lateral canals and the apical extrusion of irrigant. Methods: Thirty-two resin teeth were used. After root canal instrumentation, four lateral canals were made at 2 and 7 mm from the apex. Root canals were filled with contrast solution. The root canals were irrigated with two types of needle, 29G and 31G, with different designs (side and apical opening) and two flow rates (2 or 5 mL/min), at 1 mm short of the working length. The volume of the contrast solution in the main and lateral canals after irrigation and apical extrusion of the irrigant (mm3) were evaluated by Micro-CT, in comparison with the initial analysis. Data in percentage were analyzed by ANOVA and Tukeys tests (α = 0.05). Results: no difference among the irrigation protocols for contrast solution cleaning was observed. Higher volume of apical extrusion using needle 29G-apical opening and 5 mL/min in comparison with the same type of needle and 2 mL/min was observed (p < 0.05). Conclusion: all irrigation protocols were associated with root canals cleaning. Greater apical extrusion was observed for needle 29G-apical opening with higher irrigation flow rate (5 mL/min). Clinical implications: endodontic irrigation using a needle with apical opening and higher flow rate of solution may favor extrusion of irrigant to the periapical tissues (AU).

Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus

Abstract The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Solubility, porosity and fluid uptake of calcium silicate-based cements

Abstract Objective: To evaluate the absorption/fluid uptake, solubility and porosity of White mineral trioxide aggregate (MTA) Angelus, Biodentine (BIO), and zinc oxide-eugenol (ZOE). Material and Methods: Solubility was evaluated after immersion in distilled water for 7 and 30 days. Porosity was evaluated using digital inverted microscope, scanning electron microscope (SEM) and micro-computed tomography (micro-CT). For the fluid uptake test, specimens were immersed in Hank's balanced salt solution (HBSS) for 1, 7, 14 and 28 days. Fluid absorption, solubility and porosity of the materials were measured after each period. Statistical evaluation was performed using one-way analysis of variance (ANOVA) and Tukey tests, with a significance level at 5%. Results: After 7 and 30 days, BIO showed the highest solubility (p<0.05). All methods demonstrated that MTA had total porosity higher than BIO and ZOE (p<0.05). Micro-CT analysis showed that MTA had the highest porosity at the initial period, after its setting time (p<0.05). After 7 and 30 days, ZOE had porosity lower than MTA and BIO (p<0.05). Absorption was similar among the materials (p>0.05), and higher fluid uptake and solubility were observed for MTA in the fluid uptake test (p<0.05). Conclusions: BIO had the highest solubility in the conventional test and MTA had higher porosity and fluid uptake. ZOE had lower values of solubility, porosity and fluid uptake. Solubility, porosity and fluid uptake are related, and the tests used provided complementary data.

Antibacterial activity of intracanal medications based on calcium hydroxide and zinc oxide micro- or nanoparticles: an ex vivo study / Atividade antibacteriana de medicações intracanal à base de hidróxido de cálcio e óxido de zinco micro- e nanoparticulado: estudo ex vivo

Introduction: Nanoparticles and associations to calcium hydroxide can be used to increase antimicrobial activity. Objective: To evaluate antibacterial activity against Enterococcus faecalis and pH of intracanal medications (IM) based on calcium hydroxide (CH) and zinc oxide (ZnO) micro- or nanoparticles, and their association with 0.4% chlorhexidine (CHX). Material and method: Root canals from single-rooted human teeth were inoculated and incubated for 21 days. After sample (S1), the root canals were filled with the medications for 7 days and samples were collected immediately after medication (S2) and 7 days later (S3). Counting of CFU mL-1 was performed. Polyethylene tubes filled with the medications were used for the pH evaluation after 3, 7, 14 and 28 days. Data were submitted to ANOVA and Tukey tests (p<0.05). Result: All IM promoted elimination of E. faecalis immediately after medication (S2). All the pastes promoted a similar pH increase. Conclusion: CH/ZnO micro- or nanoparticles associated with CHX promoted greater bacterial reduction in the root canals and similar pH.

Introdução: Nanopartículas e associações ao hidróxido de cálcio podem ser usados para aumentar a ação antimicrobiana. Objetivo: Avaliar a atividade antibacteriana sobre Enterococcus faecalis e o pH de medicações intracanal (MI) à base de hidróxido de cálcio (HC) e óxido de zinco (OZn) micro- e nanoparticulado, e suas associações com clorexidina (CHX) a 0,4%. Material e método: Canais radiculares de dentes humanos unirradiculados foram inoculados e incubados por 21 dias. Após coleta (C1), os canais radiculares foram preenchidos com os medicamentos durante 7 dias e as amostras foram coletadas imediatamente após a medicação (C2) e 7 dias depois (C3). Contagem de UFC mL-1 foi realizada. Os tubos de polietileno preenchidos com os medicamentos foram utilizados para a avaliação do pH após 3, 7, 14 e 28 dias. Os dados foram submetidos aos testes de ANOVA e Tukey (p<0,05). Resultado: Todas as MI promoveram eliminação de E. faecalis imediatamente após a medicação (C2). Todas as pastas promoveram similar aumento de pH. Conclusão: HC/OZn micro- ou nanoparticulado associado com CHX promove maior redução bacteriana nos canais radiculares e pH similar.

Effect of Silver Nanoparticles on Physicochemical and Antibacterial Properties of Calcium Silicate Cements

Abstract Mineral trioxide aggregate (MTA) and Portland cement (PC) are calcium silicate cements. They have similar physicochemical, mechanical and biological properties. The addition of zirconium oxide (ZrO2) to PC provides radiopacity. Silver nanoparticles (AgNPs) may improve some properties of cements. The aim of this study was to evaluate the effect of AgNPs on physicochemical/mechanical properties and antibacterial activity of white MTA (WMTA) and PC associated with ZrO2. The following materials were evaluated: WMTA; PC 70% + ZrO2 30%; WMTA+ AgNPs; and PC 70% + ZrO2 30% + AgNPs. The study evaluated radiopacity, setting time, pH, compressive strength and solubility. For radiopacity analysis, radiographs were made alongside an aluminum (Al) step wedge. To evaluate the antibacterial activity, direct contact test was performed on planktonic cells and Enterococcus faecalis biofilm induced on bovine root dentin for 14 days. The experimental periods were 5 and 15 h. Data were obtained as CFU mL-1. The obtained data were submitted to ANOVA and Tukey tests (p<0.05). The addition of AgNPs to WMTA increased the pH, lowered the solubility and the initial and final setting times. The addition of AgNPs to PC/ZrO2 maintained the pH, lowered the solubility, and increased the setting time and compressive strength. The radiopacity of all materials was higher than 4 mmAl. The addition of AgNPs promoted an increase in antibacterial activity for calcium silicate cements and favored the physicochemical and mechanical properties of the materials.

Resumo Mineral trióxido agregado (MTA) e cimento Portland (CP) são cimentos à base de silicato de cálcio. Eles apresentam propriedades físico-químicas, mecânica e biológicas semelhantes. A adição de óxido de zircônio (ZrO2) ao CP confere radiopacidade. Nanopartículas de prata (NPsAg) podem melhorar propriedades dos cimentos. O objetivo deste estudo foi avaliar o efeito da NPsAg nas propriedades físico-químicas, mecânicas e na atividade antibacteriana do MTA branco (WMTA) e CP associado ao ZrO2. Os seguintes materiais foram avaliados: WMTA; CP 70% + ZrO2 30%; ; WMTA + NPsAg; CP 70% + ZrO2 30% + NPsAg. Foram avaliados a radiopacidade, tempo de presa, pH, resistência à compressão e solubilidade. Para análise da radiopacidade foram tiradas radiografias ao lado de uma escala de alumínio (Al). Para avaliar a atividade antibacteriana, foi realizado o teste de contato direto sobre células planctônicas e biofilme de Enterococcus faecalis formado em dentina radicular bovina durante 14 dias. Os períodos experimentais foram 5 e 15 h. Os dados foram obtidos como UFC mL-1 e submetidos aos testes de ANOVA e Tukey (p<0,05). A adição de NPsAg ao WMTA elevou o pH, diminuiu a solubilidade e os tempos de presa inicial e final. A adição de NPsAg ao CP/ZrO2 manteve o pH, diminuiu a solubilidade, aumentou o tempo de presa e a resistência à compressão. A radiopacidade de todos os materiais foi maior do que 4 mmAl. A adição de NPsAg promoveu um aumento da atividade antibacteriana dos cimentos à base de silicato de cálcio e favoreceu as propriedades físico-químicas e mecânicas dos materiais.

Solubility and bacterial sealing ability of MTA and root-end filling materials

ABSTRACT Objective To evaluate solubility and sealing ability of Mineral Trioxide Aggregate (MTA) and root-end filling materials. Material and Methods The materials evaluated were: MTA, Calcium Silicate Cement with zirconium oxide (CSC/ZrO2), and zinc oxide/eugenol (ZOE). Solubility test was performed according to ANSI/ADA. The difference between initial and final mass of the materials was analyzed after immersion in distilled water for 7 and 30 days. Retrograde cavities in human teeth with single straight root canal were performed by using ultrasonic tip CVD 9.5107-8. The cavities were filled with the evaluated materials to evaluate sealing ability using the bacterial leakage test with Enterococcus faecalis. Bacterial leakage was evaluated every 24 hours for six weeks observing the turbidity of Brain Heart infusion (BHI) medium in contact with root apex. Data were submitted to ANOVA followed by Tukey tests (solubility), and Kruskal-Wallis and Dunn tests (sealing ability) at a 5% significance level. Results For the 7-day period, ZOE presented highest solubility when compared with the other groups (p<0.05). For the 30-day period, no difference was observed among the materials. Lower bacterial leakage was observed for MTA and CSC/ZrO2, and both presented better results than ZOE (p<0.05). Conclusion MTA and CSC/ZrO2 presented better bacterial sealing capacity, which may be related to lower initial solubility observed for these materials in relation to ZOE.

Effect of Passive Ultrasonic Irrigation on Enterococcus faecalis from Root Canals: An Ex Vivo Study

Endodontic irrigation aims to clean and disinfect the root canal system. Passive ultrasonic irrigation (PUI) is based on the use of an ultrasound-activated instrument into the root canal filled with irrigant. The aim of this study was to evaluate, ex vivo, the effectiveness of PUI in eliminating Enterococcus faecalis from root canals. Seventy-five extracted human single-root teeth were used. After root canal preparation, specimens were inoculated with E. faecalis and incubated at 37 °C for 21 days. Specimens were distributed into five groups (n=15), according to the irrigation method: PUI + saline solution (PUI/SS); PUI + 1% NaOCl (PUI/NaOCl); conventional needle irrigation (CNI) + saline solution (CNI/SS); CNI + 1% NaOCl (CNI/NaOCl); No irrigation (control). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). Data were obtained in CFU mL^-1 and subjected to analysis by ANOVA and Tukey's tests at 5% significance level. The post-irrigation samples did not demonstrate statistical difference between PUI/SS and CNI/SS nor between PUI/NaOCl and CNI/NaOCl (p>0.05), but PUI/NaOCl and CNI/NaOCl had lower CFU mL^-1 number than the other groups (p>0.05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0.05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. PUI or CNI with 1% NaOCl contribute to disinfection, but are unable to eradicate E. faecalis from the root canal system.

A irrigação endodôntica visa à limpeza e desinfecção do sistema de canais radiculares. A irrigação ultrassônica passiva (IUP) baseia-se na utilização de um instrumento ultrassônico ativado no interior do canal radicular preenchido com a solução irrigadora. O objetivo deste estudo foi avaliar, ex vivo, a eficácia da IUP na eliminação de Enterococcus faecalis dos canais radiculares. Foram usados 75 dentes humanos unirradiculares extraídos. Após o preparo biomecânico dos canais radiculares, foram inoculados com E. faecalis e incubados a 37 °C por 21 dias. Os espécimes foram distribuídos em cinco grupos (n=15), de acordo com o método de irrigação: IUP + solução salina (IUP/SS); IUP + NaOCl a 1% (IUP/NaOCl); irrigação manual convencional (IMC) + solução salina (IMC/sol); IMC + NaOCl a 1% (IMC/NaOCl); Sem irrigação (controle). Foram realizadas três coletas microbiológicas: inicial (21 dias após a inoculação), pós-irrigação (imediatamente após a irrigação), e final (7 dias após a irrigação). Os dados foram obtidos em UFC mL^-1 e submetidos aos testes de ANOVA e Tukey. A coleta pós-irrigação não demonstrou diferença estatisticamente significante entre IUP/SS e IMC/SS nem entre IUP/NaOCl e IMC/NaOCl (p>0,05), mas IUP/NaOCl e IMC/NaOCl apresentaram menor número de UFC mL^-1 comparado aos outros grupos (p>0,05). Diferença estatisticamente significante foi observada entre as coletas iniciais e pós-irrigação e entre a pós-irrigação e a coleta final (p<0,05) em todos os grupos, exceto no controle. Na coleta final, todos os grupos apresentaram contagem bacteriana similar à coleta inicial. IUP ou IMC com NaOCl a 1% contribuem para a desinfecção, mas não eliminam E. faecalis do sistema de canais radiculares.

Passive ultrasonic irrigation in calcium hydroxide removal from root canals: a sem/ eds analysis

AIM: The aim of this study was to evaluate the efficacy of different lengths of time of passive ultrasonic irrigation (PUI) in removing calcium hydroxide (CH) paste from root canal, using scanning electron microscopy and energy dispersive spectrometry (SEM/EDS). MATERIAL AND METHODS: Fifty-four human premolars were used. After coronal access, a size #15 K-file was used to obtain apical patency. Root canal preparation was performed using WaveOne 40.08 instruments. CH paste was placed into the root canal. Specimens were stored in a humid environment, and after seven days, they were divided into five groups (n=12) according to the irrigation protocols: Manual­ a size #40 K-file; PUI/1­ 1 min; PUI/2­ 2 min; PUI/3­ 3 min; and Control­ without CH paste. An elementary chemical microanalysis (SEM/EDS) was performed to quantify the presence of calcium on the dentinal walls. RESULTS: The percentage of calcium was higher in all experimental groups when compared to the control group (P < 0.05); but no differences among them were found (P > 0.05). CONCLUSION: The amount of calcium hydroxide paste on the dentinal walls was not dependent on length of time of ultrasonic activation. SEM/EDS analysis seems to be a reliable method to assess CH paste removal from the root canals.

Radiographic evaluation of root canal cleaning, main and laterals, using different methods of final irrigation / Avaliação radiográfica da limpeza de canais radiculares, principal e laterais, utilizando diferentes métodos de irrigação final

Objective: To evaluate the efficacy of passive ultrasonic irrigation (PUI) using intermittent or continuous flushing and conventional manual irrigation (CMI) on the cleaning of main and simulated lateral root canals. Material and Method: The root canals of 24 artificial teeth were prepared and simulated lateral canals were made in the medium and apical thirds of the root. The specimens were divided into three groups: G1- CMI, G2- PUI 1 (intermittent flushing) and G3- PUI 2 (continuous flushing). Root canals were filled with contrast solution and the roots were radiographed pre- and post-irrigation. The digital images were transferred to Image Tool 3.0 software and the areas of root canal completely filled with contrast, and after irrigation with contrast remnant, were measured to obtain percentage data. Statistical analysis between groups was performed by ANOVA and Tukey tests. Result: In the apical third, G2 and G3 (PUI) groups showed higher percentage of cleaning than G1 (CMI) (p<0.05). Conclusion: Passive ultrasonic irrigation using intermittent flushing promoted a higher cleaning of simulated lateral canals than conventional manual irrigation in the apical third. There were no differences between groups in the main root canal and the middle third. .

Objetivo: O objetivo deste estudo foi avaliar a eficácia da irrigação ultrassônica passiva (IUP), utilizando os fluxos intermitente ou contínuo, e da irrigação manual convencional (IMC) na limpeza de canais radiculares, principal e laterais simulados. Material e Método: Os canais radiculares de 24 dentes artificiais foram preparados e os canais laterais foram confeccionados nos terços médio e apical. Os espécimes foram divididos em três grupos: G1- IMC, G2- IUP 1 (fluxo intermitente) e G3- IUP 2 (fluxo contínuo). Os canais radiculares foram preenchidos com uma solução de contraste e as raízes foram radiografadas antes e após a irrigação. As imagens digitais foram importadas para o programa Image Tool 3.0 e as áreas do canal totalmente preenchidas com o contraste, e após a irrigação, com remanescente do contraste, foram mensuradas para obtenção de dados percentuais. A análise estatística entre os grupos foi realizada por meio dos testes ANOVA e Tuckey. Resultado: No terço apical, os grupos G2 e G3 (IUP) mostraram melhor limpeza do que o grupo G1 (IMC) (p<0.05). Não houve diferenças estatisticamente significantes entre os grupos G2 e G3 (p>0.05). Conclusão: Irrigação ultrassônica passiva com fluxo intermitente promoveu melhor limpeza dos canais laterais simulados do que a irrigação manual convencional no terço apical do canal radicular. Não houve diferenças entre os grupos no canal principal e no terço médio. .

Fracture resistance of endodontically-treated teeth submitted to bleaching treatment with hydrogen peroxide and titanium dioxide nanoparticles photoactivated by LED-laser / Resistência à fratura de dentes tratados endodonticamente submetidos a tratamento clareador com peróxido de hidrogênio e nanopartículas de dióxido de titânio fotoativado por LED-laser

Objective: The aim of this study was evaluate the fracture resistance of endodontically-treated teeth after bleaching treatment using 15% hydrogen peroxide plus titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser, in comparison with protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP) or sodium perborate (SP). Material and method: After endodontic treatment, fifty bovine extracted incisors were divided into five groups (n = 10): G1- without bleaching; G2- 35HP; G3- 37CP; G4- 15HPTiO2 photoactivated by LED-laser and G5- SP. In G2 and G4, the bleaching protocol was applied in 4 sessions, with a 7 day interval between each session. In G3 and G5, the materials were kept in the pulp chamber for 21 days, but replaced every 7 days. After 21 days, the crowns were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until fracture. The data were submitted to ANOVA and Tukey tests (p = 0.05). Result: The bleaching treatment in endodontically-treated teeth with 15HP plus TiO2 nanoparticles and photoactivated by LED-laser caused reduction of the fracture resistance similarly provided by 35HP, 37CP or SP (p>0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p<0.05). Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other. .

Objetivo: Avaliar a resistência à fratura de dentes tratados endodonticamente após tratamento clareador usando peroxido de hidrogênio a 15% com nanopartículas de dióxido de titânio (15HPTiO2) fotoativado por LED-laser, em comparação aos protocolos usando peróxido de hidrogênio 35% (35HP), peróxido de carbamida 37% (37CP) ou perborato de sódio (SP). Material e método: Após tratamento endodôntico, 50 incisivos bovinos extraídos foram divididos em 5 grupos (n = 10): G1- sem clareamento; G2- 35HP; G3- 37CP; G4- 15HPTiO2 fotoativado por LED-laser e G5- SP. Nos grupos G2 e G4, o protocolo de clareamento foi aplicado em 4 sessões, com 7 dias de intervalo entre cada sessão. Nos grupos G3 e G5, os materiais foram inseridos na câmara pulpar por 21 dias e trocados a cada 7 dias. Após 21 dias, as coroas foram submetidas à força de compressão com velocidade de 0,5 mm/min, aplicada a 135º em relação ao longo eixo da raiz. empregando máquina de ensaios mecânicos, até a fratura. Os dados foram submetidos aos testes de ANOVA e Tukey (p = 0.05). Resultado: O tratamento clareador em dentes tratados endodonticamente com 15HP e nanopartículas de TiO2 fotoativado por LED-laser proporcionou redução da resistência à fratura semelhante ao 35HP, 37CP ou SP (p>0,05). Todos os tratamentos clareadores reduziram a resistência coronária à fratura quando comparados aos dentes sem tratamento (p<0,05). Conclusão: Todos os protocolos de clareamento reduziram a resistência à fratura dos dentes tratados endodonticamente, sem diferenças estatisticamente significantes entre os grupos. .

Influência do diâmetro foraminal do canal radicular, do tipo e da penetração de agulha, e do fluxo da solução irrigadora na limpeza e na extrusão apical / Influence of apical foramen diameter, design and penetration depth of the needle and irrigating solution flow rate on cleaning and apical extrusion

Introdução: A irrigação do canal radicular visa a limpeza e desinfecção do sistema de canais radiculares, sem promover extrusão apical. Objetivo: Avaliar a influência do diâmetro foraminal do canal radicular, da penetração e do tipo de agulha, e do fluxo na limpeza e na extrusão apical da solução irrigadora. Material e método: Doze dentes incisivos inferiores humanos com canal único foram instrumentados e, após ampliação foraminal com diferentes diâmetros (LK #40 e 60), os canais radiculares foram preenchidos com solução de contraste radiológico espessada com propilenoglicol e óxido de zinco. Foram utilizados dois tipos de agulhas de irrigação 27G com diferentes designs (abertura apical ou lateral), dois fluxos correspondentes a 15 ou 25 mL/min, e com penetração das agulhas em duas profundidades (3 e 6 mm aquém do ápice). Antes e após irrigação, os dentes foram radiografados utilizando um sistema radiográfico digital. As áreas do canal radicular antes (preenchido pelo contraste) e após irrigação (remanescente do contraste) foram submetidas à subtração de imagens no programa Adobe Photoshop CS4 e mensuradas por meio do programa Image Tool 3.0, obtendo o percentual de limpeza e de extrusão. Os dados foram analisados por meio dos testes ANOVA e Tukey, com nível de significância de 5%. Resultado: Não houve diferença estatística entre o diâmetro foraminal, o tipo e a profundidade de penetração da agulha, e a velocidade do fluxo de irrigação nos parâmetros limpeza (acima de 97%) e extrusão apical (menor do que 0,38 mm2), com p>0,05. Conclusão: Todos os protocolos de irrigação avaliados proporcionaram limpeza do canal radicular e pequena extrusão ...

Introduction: The root canal irrigation aims to clean and disinfect the root canal system, without causing apical extrusion. Objective: To evaluate the influence of apical foramen diameter, needle penetration depth and needle design, and the irrigating solution flow rate on the cleaning and apical extrusion. Material and method: Roots of human mandibular incisors with single-canal were instrumented and after enlarged with two different root apical sizes (40 and 60 K-files), the root canals were filled with contrast solution thickened with propylene glycol and zinc oxide. Two types of irrigation needles (27-gauge) with different designs (apical or lateral opening) were used, two flow rates corresponding to 15 or 25 mL/min and needle penetration at two depths (3 and 6 mm from the apex). Before and after irrigation, the teeth were radiographed using a digital radiographic system. Pre-irrigation (canals filled with contrast) and post-irrigation (canals with remaining contrast) images were submitted to digital subtraction using the Adobe Photoshop CS4 software and the areas were measured using the Image Tool 3.0 software, obtaining the percentage of cleaning and extrusion. Data obtained were subjected to one-way ANOVA and Tukey's tests with the significance level of 5%. Result: There was no statistical difference between the apical foramen diameter, needle penetration depth and needle design, and the irrigating solution flow rate on the cleaning results (more than 97%) and the level of apical extrusion (less than 0.38 mm2), (p>0,05). Conclusion: All irrigation protocols evaluated provided cleaning of the root canal and low apical extrusion of irrigating solution. .

Apexification with white MTA in an immature permanent tooth with dens invaginatus

Dens invaginatus, also known as “dens in dente”, is a developmental dental anomaly resulting in an invagination of the enamel organ into the dental papilla. These cases present technical difficulties to the root canal treatment. Apexification using an apical plug of mineral trioxide aggregate (MTA) has been indicated as an alternative to long-term intracanal use of calcium hydroxide in immature permanent teeth. It is considered as a simple and rapid technique. This paper reports a case of Oehlers’ Type 1 dens invaginatus in an immature permanent maxillary right lateral incisor, which presented pulp necrosis secondary to dental trauma and was treated by apexification with white MTA apical plugging followed by conventional root canal therapy. The operative procedures are described and the technique is discussed. The physical and biological properties of MTA, associated with appropriate instrumentation and obturation techniques, make this material an excellent option in the endodontic therapy of immature permanent teeth with dens invaginatus.

Incomplete vertical root fracture associated with lateral compactiontechnique: a microscopic analysis / Fratura radicular vertical incompleta associada com a técnica de condensação lateral: Análise microscópica

Objective: This study evaluated the effects of root canal obturation employing lateral compaction technique and spreader load of 1.5 kg on the incidence of complete (CVRF) or incomplete vertical root fractures (IVRF). Material and Methods: Twenty-seven distal roots of extracted human mandibular molars were used. All root canals were prepared by biomechanical step-back technique and obturated by lateral compaction technique. The prepared roots were distributed into two groups: G1- experimental (n = 17)= and G2- control (n = 10). During obturation, load of 1.5 kg was applied to a size # 30 finger spreader. Pre- and post-obturation images of the coronal portion of the roots were captured by inverted digital microscopy and analyzed by one trained examiner. Data were evaluated by Fisher’s test (p < 0.05) using GrapH Pad Prism 5.0. Results: No roots exhibited CVRF. All fractures observed before and after obturation were IVRF or “other defects”. In G2 (control group), there was no increase of IVRF number. Interestingly, G1 presented an increase in the IVRF number to 70.59% in the 12 teeth out of 17 teeth studied. The statistical analysis showed that the mean of IVRF increased significantly in G1 when compared to G2 (p < 0.05). Conclusion: The application of a 1.5 kg spreader load during lateral compaction technique does not produce complete vertical root fractures, but may produce incomplete fractures or “other defects”.

Objetivo: Este estudo avaliou os efeitos da obturação dos canais radiculares, empregando a técnica de condensação lateral com uma força do espaçador de 1,5 kg, na incidência de fraturas radiculares verticais completas (FRVC) ou incompletas (FRVI). Material e Métodos: Foram usadas 27 raízes distais de dentes molares mandibulares humanosextraídos. Todas as raízes foram instrumentadas por meio da técnica clássica ápice-coroa e obturadas pela técnica de condensação lateral. Após o preparo biomecânico, as raízes foram distribuídas em 2 grupos: G1- experimental (n = 17) e G2- controle (n = 10). Durante a obturação, uma força de 1,5 kg foi aplicada ao espaçador digital # 30. As imagens pré- e pós-obturação da superfície coronal das raízes foram capturadas por meio de um microscópio digital invertido e analisadas por um examinador treinado. Os dados obtidos foram avaliados por meio do teste de Fisher (p < 0,05) usando o programa GrapH Pad Prism 5.0. Resultados: Não foram detectadas FRVC. Todas as fraturas observadas antes e após a obturação foram FRVI ou “outros defeitos”. No G2 (grupo controle), não houve um aumento no número de FRVI. Curiosamente, G1 apresentou um aumento das FRVI em 70,59% (12/17 raízes). A análise estatística mostrou que a média de FRVI aumentou significativamente no G1 quando comparado ao G2 (p < 0,05). Conclusão: A aplicação de uma força de 1,5 kg ao espaçador durante a realização da técnica de condensação lateral não produz fraturas radiculares verticais completas, mas pode produzir fraturas incompletas ou “outros defeitos”.

Eficácia da irrigação ultrassônica passiva na limpeza e eliminação de Enterococcus faecalis dos canais radiculares / Efficacy of passive ultrasonic irrigation in cleaning and elimination of Enterococcus faecalis from root canals

O objetivo deste estudo foi avaliar a eficácia da Irrigação Ultrassônica Passiva (IUP) na limpeza e eliminação Enterococcus faecalis de canais radiculares, em comparação à Irrigação Manual Convencional (IMC). O estudo foi dividido em dois capítulos. No capítulo I, foram utilizadas raízes de 75 dentes unirradiculados humanos extraídos. Após o preparo biomecânico, os espécimes foram divididos em cinco microplacas de cultura e esterilizados em óxido de etileno. Os canais radiculares foram contaminados com Enterococcus faecalis (ATCC 29212) e incubados a 37ºC durante 21 dias. As microplacas com os espécimes foram divididas em cinco grupos de acordo com o protocolo de irrigação utilizado (n=15): G1- IUP com solução salina; G2- IUP com NaOCl 1%; G3- IMC com solução salina; G4- IMC com NaOCl 1%; G5- controle (sem irrigação). Foram realizadas três coletas microbiológicas: inicial (após 21 dias de contaminação do canal), imediatamente após irrigação e final (após 7 dias dos tratamentos realizados). Após diluições decimais seriadas e semeadura, foi determinado o número de unidades formadoras de colônia por mililitro de solução (UFC/mL). No capítulo II, foram utilizadas raízes de dentes artificiais unirradiculados. Após o preparo dos canais radiculares, foram realizados quatro canais laterais nos terços apical e médio da raiz, nas superfícies vestibular e lingual. Posteriormente, os canais foram preenchidos com uma solução de contraste radiológico. Os espécimes foram divididos aleatoriamente em três grupos de acordo com o protocolo de irrigação (n=08): GI- IMC com agulha 30G, GII- IUP1 com fluxo intermitente, GIII- IUP2 com fluxo contínuo. Antes e após irrigação, os dentes foram radiografados no sentido proximal utilizando um sistema radiográfico digital. As áreas do canal radicular e canais laterais simulados antes (preenchido pelo contraste) e após irrigação (remanescente do contraste) foram mensuradas por meio do programa Image Tool 3.0. Os dados obtidos nos dois experimentos foram analisados por meio dos testes ANOVA e Tukey, com nível de significância de 5%. Na avaliação antimicrobiana, a coleta pós-irrigação não mostrou diferença estatisticamente significante entre G1 e G3 nem entre G2 e G4 (p>0,05), mas G2 e G4 mostraram uma contagem inferior de UFC/mL comparado aos demais grupos (p<0,05). Houve diferença estatisticamente significante entre a coleta inicial e pós-preparo e entre pós-preparo e a final (p<0,05) em todos os grupos, exceto no grupo controle. Na coleta final, todos os grupos apresentaram valores similares aos da coleta final. No teste avaliando a capacidade de limpeza, não houve diferença significante entre os grupos na remoção da solução de contraste do canal radicular principal mostrando porcentagem de limpeza similar (p>0,05). Nos canais laterais simulados, os resultados não mostraram diferenças significativas entre os grupos no terço médio (p>0,05). No terço apical, o grupo IUP1 mostrou-se superior, obtendo maior porcentagem de limpeza quando comparado ao grupo de IMC com diferença significante (p<0,05). Conforme as metodologias empregadas, pode-se concluir que a IUP e IMC associada à NaOCl a 1% contribui para diminuição da contaminação sem eliminar completamente de E. faecalis do sistema de canais radiculares. Quanto à remoção da solução de contraste dos canais radiculares e canais laterais simulados, a IUP com fluxo intermitente promoveu maior limpeza de canais laterais simulados no terço apical comparada à IMC

The aim of this study was to evaluate the cleaning efficacy and elimination of Enterococcus faecalis from the root canal provided by passive ultrasonic irrigation (PUI) compared with conventional needle irrigation (CNI). The study was divided into two chapters. In chapter I, seventy-five extracted human singlerooted teeth were used. After root canal instrumentation, specimens were randomly divided into cell culture microplates. The microplates containing the specimens were wrapped and sterilized by ethylene oxide. Root canals were inoculated with Enterococcus faecalis (ATCC 29212) and incubated at 37ºC for 21 days. The microplates containing the roots were randomly divided in five groups, according to the irrigation method: G1- PUI with saline solution, G2- PUI with 1% NaOCl, G3- CNI with saline solution, G4- CNI with 1% NaOCl, G5- control (no irrigation). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). After serial decimal dilutions, the inocula were seeded and was determined the number of CFU/mL. In chapter II, single-rooted artificial teeth were used. After root canal instrumentation, four lateral canals were performed in the middle and apical thirds. After, the root canals were filled with a contrast solution. The roots were randomly divided into three groups, according to the irrigation technique (n=8): GI- IMC with 30-gauge needle, GII- IUP1 with intermittent flow and GIII- IUP2 with continuous flow. Before and after irrigation, the roots were radiographed using a digital radiographic system. The areas of the root canal and lateral canals simulated before (filled by contrast) and after irrigation (remainder of contrast) were measured using Image Tool 3.0 software. Data obtained from the two experiments were subjected to ANOVA and Tukey tests (5%). In antimicrobial test, the post-irrigation samples did not demonstrate statistically significant difference between G1 and G3 nor between G2 and G4 (p>0,05), but G2 and G4 showed a lower CFU/mL than the other groups (p<0,05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0,05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. In the ability cleaning test, there was no statistically significant difference between all groups in the removal of contrast solution of the root canal. In lateral canal simulated, the results showed no significant differences between all groups in the middle third. In the apical third, PUI1 (intermittent flow) was better, resulting greater percentage of cleaning when compared to group I (CNI) with significant differences. According with the methodologies employed, it can be concluded that PUI or CNI with 1% NaOCl contribute to the reduction of contamination without complete removal of E. faecalis from the RCS. Concerning the removal of the contrast solution of root canals and lateral canals simulated, PUI with intermittent flow was significantly effective in cleaning the lateral canals in the apical third in comparison with NCI