A feasible in vitro method to evaluate bacterial infiltration in three implant-abutment connection systems / Método in vitro factible para evaluar la infiltración bacteriana en tres sistemas de conexión implante-pilar

Introduction: Microorganism infiltration through the im-plant-abutment interface causes oral health problems such as periimplantitis, leading to implant loss. Materials and Methods: A feasible new method to quantify the Streptococcus mutans (S. mutans) infiltration through the implant-abutment interface gap is introduced in the present work. Internal hexagon (IH; n = 10), external hexagon (EH; n = 10), Morse taper (MT; n = 10), and a control for each group (n = 1) were tested. Bacteria suspension was prepared at 1.5x108 CFU/mL (CFU: colony forming units), and the implants were individually submerged up to the connection level, allowing the bacteria to contact it. The abutment was removed, and bacteria count was performed. Results: The implant sets were tested under normal bacterial growth and early and late biofilm growth conditions. Colony-forming units per mL were obtained, and the results were compared among groups. Differences in bacterial count between the MT and EH (p<0.001) and the MT and IH (p<0.001) groups were significantly higher in the MT-type implant. There was a significant increment of bacterial infiltration in the MTs submitted to late biofilm growth conditions. EH and IH connections are more effective in preventing bacterial infiltration independent of the growth condition. Conclusions: The proposed methodology is feasible to evaluate the infiltration of microorganisms through the implant-abutment interface.

Introducción: La infiltración de microorganismos a través de la interfaz implante-pilar provoca problemas de salud bucal como la periimplantitis, que conduce a la pérdida del implante. Materiales y Métodos: En el presente trabajo se presenta un nuevo método factible para cuantificar la infiltración de Streptococcus mutans (S. mutans) a través de la brecha de la interfaz implante-pilar. Se probaron el hexágono interno (IH; n = 10), el hexágono externo (EH; n = 10), el cono Morse (MT; n = 10) y un control para cada grupo (n = 1). Se preparó una suspensión de bacterias a 1,5x108 UFC/mL y los implantes se sumergieron individualmente hasta el nivel de conexión, permitiendo que las bacterias entraran en contacto con él. Resultados: Se retiró el pilar y se realizó recuento de bacterias. Los conjuntos de implantes se probaron en condiciones de crecimiento bacteriano normal y de crecimiento temprano y tardío de biopelículas. Se obtuvieron unidades formadoras de colonias por ml y los resultados se compararon entre grupos. Las diferencias en el recuento bacteriano entre los grupos MT y EH (p<0,001) y MT e IH (p<0,001) fueron significativamente mayores en el implante tipo MT. Hubo un incremento significativo de la infiltración bacteriana en los MT sometidos a condiciones tardías de crecimiento de biopelículas. Las conexiones EH e IH son más efectivas para prevenir la infiltración bacteriana independientemente de las condiciones de crecimiento. Conclusión: La metodología propuesta es factible para evaluar la infiltración de microorganismos a través de la interfaz implante-pilar.

Protocolo para la medición de espacios vacíos dentro de la obturación endodóntica con microtomografía / A protocol for the measurement of voids within the endodontic filling with microtomography

La microtomografía es un estudio que utiliza la ra-diación X para obtener imágenes de tamaños de mi-lésimas de milímetros y de alta resolución. Las imá-genes 2D son procesadas por diferentes softwares para lograr obtener volúmenes capaces de ser ana-lizados tridimensionalmente. La microtomografía es el estudio de elección a la hora de evaluar caracte-rísticas muy pequeñas con gran precisión. La obtu-ración endodóntica buscar lograr un sellado que no tenga espacios vacíos dentro de la masa de obtura-ción. Esto es importante debido a que los poros pue-den permitir, si están en contacto con la pared den-tinaria, la entrada de microorganismos al conducto radicular. El objetivo de este trabajo fue describir el procedimiento para el análisis y visualización de los espacios vacíos dentro de la obturación endodónti-ca, utilizando la microtomografía de rayos x, y esta-blecer un protocolo para ser utilizado por cualquier investigador(AU)

Microtomography is a study that uses X-radiation to obtain high-resolution images of sizes of thousandths of millimeters. The 2D images are processed by different software to obtain volumes capable of being analyzed three-dimensionally. Microtomography is the study of choice when evaluating very small features with great precision. Endodontic filling seeks to achieve a seal that does not have voids within the filling obturation. This is important because the voids can allow, if they are in contact with the dentin wall, the entry of microorganisms into the root canal. The objective of this work was to describe the procedure for the analysis and visualization of voids within the endodontic filling using microtomography and to establish the protocol to be used by any researcher (AU)

Is it necessary to pre-treat Dentine before GIC Restorations? Evidence from an in Vitro Study / É necessário pré tratar a dentina antes das restaurações de CIV? Evidência de um estudo in vitro

ABSTRACT The aim of this study was to assess the influence of differentpretreatmentapproaches on glass ionomer cement (GIC)bond strength (BS) to dentine. Sixty bovine incisors wereallocated into six groups according to substrate - sound orcariesaffecteddentine; and substrate pretreatmentapproach -no conditioning (control), polyacrylic acid for 10 s andphosphoric acid for 7 s. Teeth in the cariesaffecteddentinegroup were previously submitted to cariogenic pHcyclingchallenge. After dentine pretreatment,according to experi mentalgroups, polyethylene tubes were placed on flat dentinesurfaces and filled with GIC. Teeth were stored in distilledwater for 24 h at 37 °C and then submitted to microshear test(0.5 mm/min). Failure pattern analysis was performed understereomicroscope (400x). Data were analysed using twowayANOVA and Tukey's test (α=5%). Statistically significantdifferences were found for the pretreatmentapproach,regardless of substrate (p<0.001). The polyacrylic acid groupand control group had similar BS values, and were both betterthan the phosphoric acid group. In general, GIC had betterbonding performance in sound dentine than in cariesaffecteddentine. In conclusion, dentine pretreatmentwith polyacrylicacid did not improve the performance of GIC restoration onclinically relevant substrates.

RESUMO O objetivo deste estudo foi avaliar a influência de diferentesprétratamentosna resistência de união (RU) de cimentos deionômero de vidro (CIV) a dentina. Sessenta incisivos bovinosforam alocados em 6 grupos de acordo com o substrato -hígido ou cariado; e com a abordagem de prétratamento-sem condicionamento (controle), ácido poliacrílico por 10 s, eácido fosfórico por 7 s. Os dentes pertencentes aos grupos dedentina cariada foram previamente submetidos ao desafiocariogênico por meio da ciclagem de pH. Após o prétratamentoda dentina, de acordo com os grupos experimentais,tubos de polietileno foram colocados sobre superfícies planas dedentina e preenchidos com CIV. Os dentes foram armazenadosem água destilada por 24 h a 37°C e então submetidos ao testede microcisalhamento (0,5 mm/min). A análise do padrão defratura foi realizada em estereomicroscópio (400x). Os dadosobtidos foram analisados usando ANOVA de dois fatores e testede Tukey (α=5%). Diferença estatisticamente significante foiencontrada para as diferentes abordagens de prétratamento,independente do substrato (pp<0,001). Aplicação de ácidopoliacrílico resultou em valores de RU similares aos do grupocontrole. Entretanto, ambos os grupos mostraram um melhordesempenho quando comparado a aplicação de ácidofosfórico. De forma geral, CIV apresentou melho5 desempenhoadesivo em dentina sadia quando comparada a dentinacariada. Em conclusão, o prétratamentoem dentina comácido poliacrílico não melhora o desempenho das restauraçõesde CIV em substratos clinicamente relevantes.

Influence of Surface Sealants on Microleakage in Composite Restorations / Estudio de la Influencia de los Sellantes de Superficie sobre la Microfiltración en Restauraciones de Composite

ABSTRACT: Polymerization shrinkage of composites can generate stress that results in the formation of microgaps at the resin-enamel interface and marginal leakage. The aim of the present work was to evaluate the influence of surface sealants on microleakage in composite restorations. Enamel-dentin occlusal cavities were prepared in 30 non-carious upper and lower premolars. The cavities were restored with One Coat Bond SL and Brilliant New Generation (Coletene), following the manufacturers' instructions, and polished appropriately. The samples were randomly assigned to one of the following six treatment groups: Group I (Control-no sealant); Group II: Single Bond (3M/ESPE); Group III: Perma Seal (Ultradent); Group IV: Heliobond (Vivadent); Group V: Biscover LV (Bisco); Group VI: Bioforty (Biodinâmica). The samples were then immersed in 2 % aqueous methylene blue solution for 48 hours, and thermocycled 100 times from 5 ºC to 55 ºC. The obtained specimens were ground in a bucco-palatal orientation to reach the medial plane, and observed under a stereoscopic loupe at 40X. The degree of microleakage was evaluated by assessing the penetration of the dye to the tooth-restoration interface, using a 0 to 3 grading scale. The obtained data were analyzed using the Kruskal-Wallis non-parametric test. Significant differences were observed between all rebonded groups and the control group; no differences were observed among Single Bond, Perma Seal and bioforty, or between Heliobond and Biscover LV. It would seem convenient to apply a surface sealant over composite restorations to improve marginal integrity and reduce microleakage.

RESUMEN: La contracción de polimerización de los composites puede generar fuerzas que determinan la formación de microbrechas en la interfase resina-esmalte y filtración marginal. El objetivo de este trabajo fue evaluar la influencia de los sellantes de superficie, en restauraciones de composite, sobre la microfiltración. Se utilizaron 30 premolares superiores e inferiores, libres de caries, donde se realizaron preparaciones oclusales amelodentinarias que fueron obturadas con One Coat Bond SL y Brilliant New Generation (Coletene), siguiendo las indicaciones del fabricante y pulidas adecuadamente. Luego las muestras se distribuyeron aleatoriamente en seis grupos, según los materiales experimentales: Grupo I (Control), Grupo II: Single Bond (3M/ESPE), Grupo III: Perma Seal (Ultradent), Grupo IV: Heliobond (Vivadent), Grupo V: Biscover LV (Bisco), Grupo VI: bioforty (biodinámica). Posteriormente las piezas fueron sometidas a ciclaje térmico por 100 ciclos entre 5 ºC y 55 ºC, sumergidas en una solución acuosa de azul de metileno al 2 % durante 48 horas y desgastadas en sentido V-P, hasta el plano medial, para ser observadas con lupa estereoscópica a 40 X. El grado de filtración se evaluó por la penetración del colorante en la interfase diente-restauración en una escala de O a 3. Los datos obtenidos fueron analizados mediante la muestra no paramétrica de Kruskal-Wallis. Se encontraron diferencias significativas de todos los grupos con respecto al grupo control (p= 0,0167), no existiendo significación entre Single Bond, Perma Seal y bioforty ni entre Heliobond y Biscover LV. En restauraciones de composite, sería conveniente la aplicación de sellantes de superficie para mejorar la integridad marginal y disminuir la microfiltración.

Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT® hydro

ABSTRACT Objectives The aim of this study was to characterise the new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface. Conclusion Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface.

Capacidad de sellado coronario de dos cementos endodónticos a base de óxido de cinc y eugenol: un estudio ex vivo / Coronal sealing ability of two zinc-oxide and eugenol-based endodontic sealers: an ex vivo study

Objetivo: comparar, mediante un modelo de filtración bacteriana, la capacidad de sellado coronario de obturaciones realizadas con conos de gutapercha complementados con Kleppmetthasona (KMS; Klepp/Raysan, Buenos Aires, Argentina); y Pulp Canal Sealer EWT (PCS; Sybron-Endo, Glendora, Estados Unidos). Materiales y métodos: se utilizaron 24 (n=24) premolares humanos sanos extraídos. En todos los casos, los conductos radiculares fueron preparados por medio de instrumentos rotatorios ProTaper Universal (Dentsply/Tulsa Dental, Tulsa, OK, Estados Unidos) hasta un instrumento #F3. Se distribuyeron 20 de los dientes en dos grupos experimentales (Grupo I y Grupo II) de 10 (n=10) especímenes cada uno. En cada grupo se agregaron un especimen de control positivo (n=1) y un especimen de control negativo (n=1). En el grupo 1, los conductos se obturaron con un cono de gutapercha ProTaper de conicidad correspondiente al instrumento #F3 y se complementó mediante la condensación lateral de conos accesorios. El sellador utilizado fue KMS, a base de óxido de cinc y eugenol que incluye un corticoide en su composición. En el Grupo 2 se realizó el mismo procedimiento, pero se utilizó PCS, un sellador a base de óxido de cinc y eugenol convencional. Para cada especimen, el proceso de filtración bacteriana se realizó por medio de un sistema individual de doble cámara, cada uno de las cuales contenía el medio de cultivo. En todos los casos, el medio de la cámara superior se inoculó con un cultivo de Enterococcus faecalis y el sistema se incubó durante 60 días. En la cámara inferior, la filtración bacteriana se controló diariamente hasta la finalización del experimento. Los datos registrados se analizaron con la prueba de supervivencia de Kaplan-Meyer yla prueba de Fischer, con un nivel de significación de P<0.05. Resultados: todos los controles positivos demostraron filtración bacteriana dentro de las primeras 48 horas. No hubo filtración en ninguno de los controles negativos.

A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline / Avaliação laboratorial da infiltração bacteriana em plugs apicais de mta expostos ao tampão fosfato-salino

O presente estudo avaliou a influência da exposição do agregado de trióxido mineral (MTA) – com e sem cloreto decálcio (CaCl2) – ao tampão fosfato-salino (PBS) sobre a microinfiltração apical. Sessenta segmentos radiculares foram divididos em 4 grupos experimentais (n=15). As cavidades apicais foram preenchidas com MTA, com ou sem CaCl2, e os canais radiculares receberam uma bolinha de algodão umedecida ou PBS, como medicação intracanal: 1) MTA/bolinha de algodão umedecida; 2) MTA/PBS; 3) MTA+10%CaCl2/ bolinha de algodão umedecida; 4) MTA+10% CaCl2/PBS. Após 2 meses, a penetração de E. faecalis ao longo dos plugs apicais foi avaliada. As amostras foram observadas semanal -mente durante 70 dias e a infiltração detectada através da turbidez do meio em contato com os segmentos radiculares. Dentes pertencentes aos grupos controle (n=2) foram mantidos completamente impermeáveis ou sem plug apical. A análise de sobrevivência e a comparação das curvas foram realizadas por meio dos testes Kaplan-Meier e Log-rank (p<0.05), respectiva -mente. Todas as amostras do grupo controle positivo apresentaram evidência de infiltração dentro de 24h, enquanto nenhuma amostra do grupo controle negativo apresentou infiltração aolongo dos 70 dias. Não houve diferença significativa entre os grupos experimentais (p=0.102). O uso do PBS como medicação intracanal pode melhorar a capacidade de selamento do MTA,mas não é capaz de impedir a infiltração bacteriana. A adição de CaCl2 ao MTA não melhora sua capacidade de selamento.

This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride(CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2months, E. faecalis penetration was analyzed a long the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan–Meier method was used to analyze survival and the Log-rank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statisticall y significant difference among the experimental groups (p=0.102).The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.

Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1), with gutta-percha + Sealapex (G2), and with gutta-percha + AH Plus (G3). Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0), applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively), whereas G1 showed significantly higher values (mean: 105.2 ng mL-1). At 60 days, leakage values were 182.6 ng mL-1for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

Capacidad de sellado de tres agentes cementantes para restauraciones coronarias indirectas / Sealing ability of three luting agents used for cementation of indirect coronal restorations

Objetivo: comparar ex vivo, por medio de un modelo de filtración bacteriana, la capacidad de sellado de un ionómero vítreo modificado con resinas, de un ionómero vítreo convencional y de un cemento de fosfato de cinc, utilizados para la cementación de coronas coladas (AU). Materiales y métodos: un total de 30 premolares humanos sanos, extraídos, fueron preparados de forma estandarizada para recibir una corona metálica con terminación en chamfer sobre dentina. Se realizaron impresiones, se vaciaron en densita tipo IV, se enceraron y se colaron en aleación de oro tipo III. Luego fueron separadas al azar en tres grupos de 10 (n=10) especímenes cada uno. Las coronas del grupo 1 fueron cementadas con Rely-X Luting Plus (3M/ESPE); y las del grupo 2, con Ketac-Cem (3m/ESPE); y las del grupo 3 (control), con el cemento de fosfato de cinc Harvard Cement (Harvard Debtal International GmbH, Hoppengarten, Alemania). Todos los especímenes fueron termociclados. Posteriormente, la superficie metálica oclusal fue reducida 1 mm hasta exponer la dentina, y las muestras se esterilizaron en autoclave. El proceso de filtración se realizó por medio de un sistema de doble cámara con medio de cultivo. El medio de la cámara superior se inoculó con E. faecalis y el sistema fue incubado durante 60 días. En la cámara inferior, la filtración bacteriana se controló diariamente. Los datos registrados fueron analizados por medio de las pruebas de Kaplan-Meyer y de Fischer, con un nivel de significación de P<0,05. Resultados: el tiempo de supervivencia para Rely-X Luting Plus no pudo ser estimado, ya que fue superior a los 60 días, tiempo máximo de duración de la experiencia. Para Ketac-Cem fue de 60 días, con un intervalo de confianza (95 por ciento) de 29,6-90,4. Y para Harvard Cement fue de 40 días, con un intervalo de confianza de 32,6-47,4. Las diferencias entre los grupos fueron estadísticamente significativas. Conclusión: Rely-X Plus demostró una capacidad de sellado superior.

Efecto de la humedad sobre el fraguado del MTA: estudio "in vitro" / The effect of moisture on the setting of MTA: an in vitro study

Objetivo: evaluar el efecto de la humedad sobre el fraguado del ProRoot MTA, en sus superficies intraconducto y apical. Materiales y métodos: se emplearon 20 probetas cilíndricas huecas, de silicona transparente, instaladas sobre un block de gomaespuma humedecido con suero fisiológico. Las probetas fueron obturadas con 4 mm de espesor de ProRoot MTA (Dentsply Tulsa Dental, OK, Estados Unidos) y divididas al azar en dos grupos de 10 probetas cada uno. En el grupo 1 se colocó sobre el material una torunda de algodón seco, mientras que en el grupo 2 el algodón estaba humedecido con agua destilada. Los orificios superiores de las probetas se obturaron con cemento de óxido de zinc reforzado Zoer´s (Laboratorio SL SA, Buenos Aires, Argentina). Los especímenes se mantuvieron a 37ºC de temperatura y 100% de humedad. A las 4 y 6 horas fueron removidos de la gomaespuma, se retiraron el Zoer´s y el algodón y se registró el fraguado en las superficies del MTA intraconducto -subgrupos 1A y 2A- y apical -subgrupos 1B y 2B-, empleando una aguja Gillmore. El procedimiento estadístico fue realizado mediante la prueba de Chi cuadrado. Resultados: a las 4 horas, se encontraba fraguado el 50 por ciento de las muestras del subgrupo 1A, el 80 por ciento de las del subgrupo 1B, el 90 por ciento de las del subgrupo 2A y el 100 por ciento de las del subgrupo 2B. A las 6 horas de control, todas las muestras se encontraban fraguadas (100 por ciento). Se registraron diferencias estadísticamente significativas -a las 4 horas- entre los subgrupos 1A y 2A (P<0,05); entre los subgrupos 1ºB y 2B no las hubo (P>0,05). Tampoco hubo diferencias estadísticamente significativas entre los subgrupos 1A y 1B ni entre los subgrupos 2A y 2B (P>0,05). Conclusión: la presencia de un algodón húmedo en contacto con el MTA acelera el fraguado de la superficie intraconducto del material, en tanto no influye en el fraguado de su superficie apical

A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols

The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin. Objective: The objective of the present study was to evaluate the effect of different irrigant protocols on coronal bacterial microleakage of gutta-percha/AH Plus and Resilon/Real Seal Self-etch systems. Material and Methods: One hundred ninety pre-molars were used. The teeth were divided into 18 experimental groups according to the irrigation protocols and filling materials used. The protocols used were: distilled water; sodium hypochlorite (NaOCl)+eDTA; NaOCl+H3PO4; NaOCl+eDTA+chlorhexidine (CHX); NaOCl+H3PO4+CHX; CHX+eDTA; CHX+ H3PO4; CHX+eDTA+CHX and CHX+H3PO4+CHX. Gutta-percha/AH Plus or Resilon/Real Seal Se were used as root-filling materials. The coronal microleakage was evaluated for 90 days against Enterococcus faecalis. Data were statistically analyzed using Kaplan-Meier survival test, Kruskal-Wallis and Mann-Whitney tests. Results: No significant difference was verified in the groups using chlorhexidine or sodium hypochlorite during the chemo-mechanical preparation followed by eDTA or phosphoric acid for smear layer removal. The same results were found for filling materials. However, the statistical analyses revealed that a final flush with 2% chlorhexidine reduced significantly the coronal microleakage. Conclusion: A final flush with 2% chlorhexidine after smear layer removal reduces coronal microleakage of teeth filled with gutta-percha/AH Plus or Resilon/Real Seal SE. .

Ex vivo microbial leakage after using different final irrigation regimens with chlorhexidine

Objective: To assess the influence of final irrigation protocols with chlorhexidine in the coronal leakage of Enterococcus faecalis in filled root canals. Material and Methods: Seventy single-root canals from extracted teeth were prepared using ProTaper instruments. The irrigation protocol accomplished an alternating irrigation with 5 mL of 2.5% sodium hypochlorite (NaOCI) and 17% EDTA between each file. The teeth were randomly divided into four experimental groups (n=15) according to the final irrigation regimen: group 1, without final irrigation; group 2, irrigation with 10 mL 2.0% chlorhexidine (CHX); group 3, with a final application of EC40™; and group 4, irrigation with the combination (1:1) of 0.2% CHX + 0.1% cetrimide (CTR). All the teeth were mounted in a two-chamber apparatus and the coronal access was exposed to E. faecalis. The presence of turbidity in the BHI broth over a period of 180 days was observed. The Friedman test was used for statistical analysis. Results: EC40™ varnish showed the least leakage at 180 days, and was statistically similar to 2% CHX. No significant differences were observed between the group without final irrigation and the 2% CHX group or 0.2% CHX + 0.1% CTR. Conclusions: In this ex vivo study, EC40™ showed the longest delayed coronal leakage of E. faecalis, although without significant differences from 2% CHX.

Sealability of MTA and calcium hydroxidecontaining sealers

OBJECTIVES: The aim of this study was to evaluate the apical sealability of Fillapex®, endo-CPM-Sealer® and Sealapex®. Material and Methods: Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukey's tests at 5% significance level. Results: Fillapex® and Sealapex® showed significantly less dye leakage than endo-CPM-Sealer® (p<0.05). Conclusions: It was concluded that Fillapex® and Sealapex® were able to prevent apical dye leakage differently from endo-CPM-Sealer®.

Evaluación de tres sistemas de endopostes: segunda parte: evaluación in vitro de microfiltración de tres sistemas de endopostes / Evaluation of three endoposts systems: second part: an in vitro microleakage evaluation of three endoposts systems

Objetivos: en este estudio in vitro, se comparó la microfiltración de tres sistemas de endopostes (colados, de titanio y de cerámica inyectada con estructura de circonia), utilizados para reconstruir incisivos centrales, caninos y premolares unirradiculares superiores. Materiales y métodos: se prepararon 90 muestras. Para las pruebas de microfiltración, los elementos se sometieron primero a un test de termociclado (5º y 55ºC), luego se los sumergió en una solución de azul de metileno al 0,5 por ciento. Finalmente fueron desgastados en sentido longitdinal en una de sus caras proximales, donde posteriormente se midió la penetración y concentración del colorante en un analizador de imágenes. Los datos obtenidos fueron analizados estadísticamente con el test de Kruskal-Wallis. Resultados: los resultados demostraron diferencias no significativas, lo que nos permitió concluir que la preparación adecuada del conducto radicular y del remanente dentario, el uso de un cemento adhesivo y la elección correcta del sistema de postes a utilizar en la reconstrucción del diente desvitalizado, nos garantiza una mejor resistencia y una disminución de la filtración de la interface diente-cemento-perno, al haber un correcto sellado de la restauración.

Efeito do Bisel no Esmalte Sobre a Microinfiltração em Preparos Classe I em Molares Decíduos / Effect of Enamel Bevel on Microleakage in Class I Cavities in Primary Molars

Objetivo: Avaliar in vitro a influência da terminação marginal do preparo cavitário Classe I sobre a qualidade adesiva em restaurações compósitas realizadas em primeiros e segundos molares decíduos.Método: Dois preparos cavitários foram realizados na oclusal de vinte molares decíduos hígidos, sendo 20 preparos em primeiros molares e 20 em segundos molares, totalizando quarenta preparos cavitários. Após escolha aleatória, 20 preparos não receberam o bisel reto (grupo controle, GI, n=20) enquanto os demais preparos, grupo experimental, (GII, n=20) receberam um bisel reto com 0,5 mm de extensão no ângulo cavo û superficial feito com ponta diamantada ultra-fina 2200 FF. Para o procedimento restaurador, utilizou-se condicionamento ácido total com ácido fosfórico a 37% por 30s, sistema adesivo Prime & Bond NT® e compósito TPH® Spectrum cor A2. Para avaliação da qualidade adesiva, os dentes foram isolados com verniz, exceto às restaurações e 1,0 mm além das suas margens, e permaneceram em contato direto com uma solução aquosa de nitrato de prata a 50%, por 24 h. Em seguida, estes dentes foram clivados mesiodistalmente, e as restaurações avaliadas com 40 vezes de aumento. Dois avaliadores calibrados classificaram independentemente as restaurações de acordo com escores que variaram de zero (ausência de microinfiltração) a três (máxima microinfiltração). Os dados foram analisados descritivamente e tratados com os testes de Wilcoxon, Qui-quadrado e exato de Fisher a um nível de confiança de 95%.Resultados: O GII mostrou maiores escores de microinfiltração que o GI (p<0.001; p=0.0001). Os primeiros molares decíduos sofreram mais microinfiltração na presença de bisel (p=0.0003). Conclusão: O bisel no ângulo cavo-superficial em preparos Classe I aumentou a infiltração marginal nas restaurações compósitas em molares decíduos, principalmente nos primeiros molares

Objective: To evaluate in vitro the influence of Class I cavity marginal preparation on the adhesive quality in composite resin restorations placed in first and second primary molars.Method: Two cavities were prepared on the oclusal face of twenty sound primary molars, being twenty cavities in first molars and twenty in second molars, totalizing forty cavities. After random allocation, twenty cavities did not receive a straight bevel (control group, GI, n=20) while in the other cavities (experimental group, GII, n=20) a 0.5 mm straight bevel was made in the cavosurface angle with ultra-fine diamond bur 2200 FF. The restorative procedure included 37% phosphoric acid etching for 30 s, application of Prime & Bond NT®adhesive system and placement of TPH®Spectrum composite resin (shade A2). For evaluation of the adhesive quality, the teeth were coated with varnish, except for the restorations and a 1.0-mm-wide window beyond its margins, and were immersed in a 50% silver nitrate aqueous solution for 24 h. Next, the teeth were cleaved mesiodistally and the restorations were examined at ×40 magnification. Two independent calibrated examiners classified the restorations according to scores from zero (absence of microleakage) to three (maximum microleakage). Data were analyzed descriptively and treated with Wilcoxon, Chi-Square and FisherÆs exact tests at a confidence level of 95%.Results: GII presented higher microleakage scores than GI (p<0.001; p=0.0001). The primary first molars showed greater microleakage in the presence of bevel (p=0.0003). Conclusion: Beveling the cavosurface angle in Class I cavities increased marginal microleakage in the composite resin restorations placed in primary molars, especially in the first molars

Effect of calcium hydroxide-based dressing on apical sealing in immature teeth filled with MTA / Efeito da medicação à base de hidróxido de cálcio no selamento apical de dentes imaturos obturados com MTA

OBJECTIVES: To evaluate the effects of a calcium hydroxide-based intracanal dressing on the initialapical adaptation and leakage of fillings performed with mineral trioxide aggregate (MTA) in teeth withopen apices. STUDY DESIGN: A total of 24 canals were manually prepared and randomly divided intotwo groups (n = 12). In the experimental group, root canals were dressed with calcium hydroxide-basedpaste for 21 days; in the control group, no medication was applied prior to the filling of root canalswith mineral trioxide aggregate. Apical sealing was evaluated on the basis of rhodamine B penetrationand the detection of microscopic apical defects at the filling interface (SEM). The data obtained werecompared by means of t- and Fisher’s Exact tests (á = 0.05). RESULT S: The difference in mean dyeleakage between the experimental (5.03±1.97 mm) and control (4.14±1.13 mm) groups was not statisticallysignificant (ñ < 0.05). The number of microscopic fissures at the experimental group interface (2/12)was significantly lower than that observed for the control group (9/12) (ñ < 0.05). CONCLUSIONS:The use of a calcium hydroxide-based intracanal dressing did not interfere with the initial apical sealingof immature teeth filled with MTA.

OBJETIVOS: Avaliar os efeitos da medicação intracanal à base de hidróxido de cálcio sobre a adaptação apical inicial e selamento de obturações realizadas com agregado de trióxido mineral (MTA) em dentes com ápice aberto. PLANEJAMENTO DO ESTUDO: Um total de 24 canais foram manualmente preparados e aleatoriamente divididosem dois grupos (n = 12). No grupo experimental, canais radiculares foram preenchidos com pasta à base de hidróxido de cálcio por 21 dias; no grupo controle, nenhuma medicação foi aplicada antes da obturação dos canais com agregado de trióxido mineral. O selamento apical foi avaliado com base na penetração de rodamina B e na detecção microscópica de defeitos apicais na interface das obturações (MEV). Os dados obtidos foram comparados por intermédio dos testes “t” e Exato de Fisher (α = 0,05). RESULTADOS: A diferença nos níveis médios de infiltraçãoentre os grupos experimental (5.03±1.97 mm) e controle (4.14±1.13 mm) não se mostrou estatisticamente significante (ρ < 0,05). O número de fendas microscópicas na interface das obturações do grupo experimental (2/12) apresentou-se estatisticamente inferior ao detectado para o grupo controle (9/12) (ρ < 0,05). CONCLUSÕES: O uso de medicação intracanal à base de hidróxido de cálcio não interferiu no selamento apical inicial de dentes imaturos obturados com MTA.

Seal capability of interim post and core crown with temporary cements

The purpose of the present study was to evaluate the in vitro seal capability of interim post and core crown restorations. Eighty teeth were selected and divided into 8 groups. Four experimental groups received interim posts and core crowns. Half of each group was decoronated at the cementum-enamel junction, groups PCCH and PCZO. The other half was sectioned 2 mm coronal to the cementum-enamel junction, groups PCrZO and PCrCH. The interim post and core crowns were luted with Rely X Temp NE, groups PCrZO and PCZO; Hydro C was used for Groups PCrCH and PCCH. The control groups, PC and PCr, received uncoated post and core crowns; groups OTg and OT were left without interim post and core crowns and were totally open. Infiltration was accessed by dye exposure followed by demineralization of the teeth. The length of the infiltration was measured using digital images taken from the specimens. The images were inserted into the Image Tool 3.0 software. Kruskal-Wallis analysis of variance and Dunn's multiple comparison method were used to test for significant differences among test groups (P < .05). Groups PCrZO and PCrCH showed the least dye penetration, followed by groups PCZO and PCCH. Teeth restored with interim post and core crowns will be subject to leakage. Ethics Committee: 095/2008.

Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs

OBJECTIVE: This study used dye leakage assay and scanning electron microscopy to evaluate, respectively, the sealing ability and marginal adaptation of three root-end filling materials used as apical plugs, as well as the possible correlation between these properties. MATERIAL AND METHODS: Ninety-eight single-rooted human teeth were prepared to simulate an open apex. The teeth were allocated to three experimental groups (n = 30), which received a 5-mm thick apical plug of (1) gray MTA AngelusTM, (2) CPM TM and (3) MBPc, and two controls groups (n = 4). After immersion in 0.2 percent Rhodamine B solution for 48 h, the teeth were sectioned longitudinally and analyzed by Image Tool 3.0 software. The marginal adaptation between apical plugs and the root canal walls were analyzed by SEM. RESULTS: MBPc had significantly less (p<0.05) apical leakage than the other materials. Regarding marginal adaptation, CPM TM showed the best numerical results, though without statistical significance from the other materials (p<0.05). There was no correlation between the two properties. CONCLUSIONS: When used as apical plugs, the tested root-end filling materials had similar marginal adaptation to the dentin walls, but MBPc had the best sealing ability, as demonstrated by the least apical leakage from all tested materials.

Dimensional alterations and solubility of new endodontic sealers

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

O presente estudo avaliou a alteração dimensional e solubilidade de 2 cimentos experimentais (à base de resina do óleo de Copaíba - Biosealer e cimento do polímero da mamona - Poliquil), mantidos em diferentes meios de armazenamento. Foram confeccionados 20 espécimes de cada cimento com 3 mm de diâmetro e 2 mm de altura os quais foram divididos em 2 grupos (n=10) de acordo com o meio de armazenamento (fluido tissular simulado ou água destilada). Os espécimes foram atidos nas soluções durante 90 dias, sendo removidos a cada 30 dias para pesagem das amostras, no entanto as soluções foram trocadas a cada 15 dias. Os resultados foram submetidos aos testes de Dunn (5 por cento) e Mann-Whitney. Os meios de armazenamento causaram influência no comportamento dos cimentos em relação ao peso (p=0,0001). Poliquil apresentou alta variação de peso independente da solução (p=0,239). Biosealer também apresentou alta variação de peso independente da solução (p=0,0001). A solubilidade do Biosealer foi diferente do Poliquil, entretanto, ambos cimentos mostraram baixa solubilidade no fluido tissular simulado. Nas condições do experimento, nenhum cimento está de acordo com a especificação da ADA.