Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability.

OBJECTIVES: The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC). MATERIALS AND METHODS: Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM. RESULTS: The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste. CONCLUSIONS: All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results. CLINICAL RELEVANCE: Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Human phase I in vitro liver metabolism of two bisphenolic diglycidyl ethers BADGE and BFDGE.

Root canal sealers are commonly used to endodontically treat teeth with periapical infections. Some root canal sealers based on epoxy resin contain bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The presence of these chemicals is of concern due to the close contact to the blood stream at the apex and the long setting times of up to 24 h. These chemicals, or any of their degradation products or metabolites, can then exert their toxic effects before being excreted. This study aimed to identify the phase I in vitro biotransformation products of BADGE and BFDGE using human liver microsomes. During incubation with microsomal fractions, the epoxides were rapidly hydrolysed in a NADPH independent manner resulting in the formation of BADGE.2H2O and BFDGE.2H2O. Further, oxidative reactions, such as hydroxylation and carboxylation, generated other BADGE metabolites, such as BADGE.2H2O-OH and BADGE.H2O.COOH, respectively. For BFDGE, further oxidation of BFDGE.2H2O led to the newly reported carboxylic acid, BFDGE.H2O.COOH. In total, three specific metabolites have been identified which can serve in future human biomonitoring studies of BADGE and BFDGE.

The synergistic effects of SrF2 nanoparticles, YSZ nanoparticles, and poly-ε-l-lysin on physicomechanical, ion release, and antibacterial-cellular behavior of the flowable dental composites.

Resin-based pit-and-fissure sealants (flowable resin composites) were formulated using bisphenol-A-glycerolatedimethacrylate (Bis-GMA)-triethylene glycol dimethacrylate-(TEGDMA)-diurethanedimethacrylate (UDMA) mixed monomers and multiple fillers, including synthetic strontium fluoride (SrF2) nanoparticles as a fluoride-releasing and antibacterial agent, yttria-stabilized zirconia (YSZ) nanoparticles as an auxiliary filler, and poly-ε-l-lysin (ε-PL) as an auxiliary antibacterial agent. Based on the physical, mechanical and initial antibacterial properties, the formulated nano-sealant containing 5 wt% SrF2, 5 wt% YSZ and 0.5 wt% ε-PL was selected as the optimal specimen and examined for ion release and cytotoxicity. The results showed an average release rate of 0.87 µg·cm-2·day-1 in the aqueous medium (pH 6.9) and 1.58 µg·cm-2·day-1 in acidic medium (pH 4.0). The maximum cytotoxicity of 20% toward human bone marrow mesenchymal stem cells (hMSCs) was observed according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) cytotoxicity assay and acridine orange staining test. A synergy between SrF2 nanoparticles and ε-PL exhibited a better antibacterial activity in terms of colony reduction compared to the other samples. However, the inclusion of SrF2 and ε-PL caused mechanically weakening of the sealants that was partly compensated by incorporation of YSZ nanoparticles (up to 10 wt%).

Bond strength and solubility of a novel polydimethylsiloxane-gutta-percha calcium silicate-containing root canal sealer.

BACKGROUND: Endodontic sealers are essential for sealing gutta-percha to the dentin walls. They help to ensure that the canal remains free of microorganisms which might lead to infection. In order to perform their intended function, the sealers should properly adhere to the dentin walls and remain insoluble when set in the canal. OBJECTIVES: The purpose of this study was to evaluate the bond strength and solubility of a novel polydimethylsiloxane-gutta-percha calcium silicate-containing root canal sealer (GuttaFlow® bioseal) and compare it with the zinc oxide and eugenol sealer (Zical®). MATERIAL AND METHODS: The endodontic sealers used in this study were GuttaFlow bioseal and Zical. The bond strength was assessed using push-out bond strength test in 3 root segments: coronal, middle and apical. The solubility was tested according to the American National Standards Institute / American Dental Association (ANSI/ADA) specification No. 57 at 3 different time intervals: 1, 7 and 14 days. RESULTS: The push-out bond strength in all root segments was significantly higher in Zical compared to GuttaFlow bioseal. The solubility was significantly higher on day 1 and 7 in Zical compared to GuttaFlow bioseal, and on day 14, the difference between them was not significant. CONCLUSIONS: Within the limitations of this study, the endodontic sealer GuttaFlow bioseal showed low bond strength values compared to Zical. The solubility of the set GuttaFlow bioseal and Zical were both within the recommended ANSI/ADA levels.

Addition of phosphates and chlorhexidine to resin-modified MTA materials.

To evaluate the properties of experimental mineral trioxide aggregate (MTA) resin-modified materials for root-end filling procedures, varying their compositions regarding the addition of hydroxiapatite (HA) or dicalcium phosphate dihydrate, with or without chlorhexidine digluconate. White MTA (Angelus, Londrina, Brazil) was used as a reference material. Degree of conversion (DC) was evaluated by Fourier transformed infrared (FTIr) spectroscopy (n = 5). Flowability (n = 3) and radiopacity (n = 3) were evaluated following ISO 6876:2001 methods. For splitting tensile strength analysis, cylindrical samples (n = 10) were subjected to compressive load using a universal testing machine (Instron Corporation, Norwood, MA). Water sorption and solubility tests were performed according to ISO 4049:2009 methods. Calcium ion release and pH analysis (n = 10) were evaluated using a pH meter (Orion, Watsonville, CA). Cytotoxicity (n = 8) of materials extracts was evaluated as cell viability percentage. Statistical analysis was performed using Kolmogorov-Smirnov for normal distribution and data was subjected to one-way ANOVA and Tukey test (α = 0.05). Addition of chlorhexidine digluconate reduced DC mean values for experimental materials (<50%). White MTA demonstrated lower flowability (5.3 mm) and higher radiopacity (9.8 mm Al), splitting tensile strength (9.1 MPa), solubility (8.2 µg/mm3 ), calcium ion release (~26.5 ppm), cytotoxicity (55.2%), and pH mean values (10.8), when compared to experimental materials. All groups demonstrated a decrease in calcium release (<85%) and pH (<13%). Formulation containing HA demonstrated similar pH values after 28 days when compared to white MTA. Evaluated experimental resin-modified MTA based materials without chlorhexidine digluconate showed satisfactory results for all physico-chemical properties tested and cytotoxicity. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2195-2201, 2019.

Sealer penetration and adaptation in root canals with the butterfly effect.

The butterfly effect is a phenomenon seen in some roots and is related to density of dentinal tubules. The aim was to investigate penetration depth and adaptation quality of root canal sealers and ProRoot MTA into bucco-lingual and mesio-distal aspects of roots with and without the effect. One hundred and twenty teeth were decoronated at the cemento-enamel junction. Canals were prepared and assigned to obturation groups: gutta-percha with a sealer (AH Plus, EndoREZ, Kerr Pulp Canal Sealer, MTA Fillapex) or ProRoot MTA alone (each containing 10 butterfly and 10 non-butterfly roots). Root sectioning yielded coronal and middle samples. Confocal laser scanning and scanning electron microscopy were used to assess penetration and adaptation. Teeth with the effect had greater mean penetration bucco-lingually (766 µm) than mesio-distally (184 µm, P = 0.003). Coronal sections had greater penetration (430 µm) compared with middle (247 µm, P = 0.006). In conclusion, greater penetration in roots with the effect may improve treatment outcomes.

Effect of Different Irrigation Systems on Sealer Penetration into Dentinal Tubules.

INTRODUCTION: Different irrigation systems have been developed to improve the efficacy and distribution of the irrigants. The aim of this study was to compare the effect of conventional endodontic needle irrigation with other irrigant delivery and/or agitation systems on sealer penetration into dentinal tubules. METHODS: Fifty single-rooted teeth with round-shaped root canals were distributed in 5 homogeneous groups characterized by the different cleansing system used: conventional endodontic needle irrigation, EndoActivator, Irrisafe, Self-Adjusting File, and EndoVac. After instrumentation, all teeth were filled by Thermafil obturators and rhodamine B dye labeled TopSeal sealer. Teeth were transversally sectioned at 2-, 5-, and 7-mm levels from the apex and observed under confocal laser scanning microscope. Maximum, mean, and percentage of sealer penetration inside tubules around the root canal were measured. Moreover, the integrity of the sealer layer perimeter was evaluated. RESULTS: No significant differences both in mean (p > .05) and in maximum penetration depth (p > .05) were observed among groups, whereas both parameters showed an increased trend within each group from the 2- to the 7-mm level from apex. Similarly, the percentage of penetration around the root canal wall did not differ among groups (p > .05) and showed an increasing trend within each group from the apical to the coronal portion of the canal. CONCLUSIONS: Sealer penetration into dentinal tubules is not affected by the irrigant delivery and/or agitation systems studied. Thermafil with TopSeal technique achieves complete sealer perimeter integrity in all groups.

Cytotoxicity and Antimicrobial Effects of a New Fast-Set MTA.

Purpose. To compare the biocompatibility and antimicrobial effectiveness of the new Fast-Set MTA (FS-MTA) with ProRoot MTA (RS-MTA). Methods. The agar overlay method with neutral red dye was used. L929 mouse fibroblast cells were cultured. The liquid and oil extracts and solid test material were placed on the agar overlay, four samples for each material. Phenol was used as the positive control and cottonseed oil and MEM extracts were used as negative controls. Cytotoxicity was examined by measuring the zones of decolorization and evaluating cell lysis under an inverted microscope using the established criteria after 24 and 48 hours. The antimicrobial test was performed using the Kirby-Bauer disk-diffusion method against S. mutans, E. faecalis, F. nucleatum, P. gingivalis, and P. intermedia. The size of the zone of inhibition was measured in millimeters. Results. There was no zone of decolorization seen under or around the test materials for FS-MTA and RS-MTA at 24 and 48 hours. The antimicrobial test demonstrated no inhibitory effect of FS-MTA or RS-MTA on any bacterial species after 24 and 48 hours. Conclusions. There was no cytotoxicity or bacterial inhibition observed by the new Fast-Set MTA when compared to the ProRoot MTA after setting.

Dentinal Tubule Penetration of Tricalcium Silicate Sealers.

INTRODUCTION: The treatments for which mineral trioxide aggregate (MTA)-based materials can be used in dentistry are expanding. Smaller particle size and easier handling properties have allowed the advent of tricalcium silicate sealers including EndoSequence BC Sealer (Brasseler USA, Savannah, GA), QuickSet2 (Avalon Biomed, Bradenton, FL), NeoMTA Plus (Avalon Biomed), and MTA Fillapex (Angelus, Londrina, Brazil). The objective of this study was to measure the tubule penetration with these sealers using continuous wave (CW) and single-cone (SC) obturation techniques. METHODS: Eighty single-rooted teeth were randomly divided into 8 groups of 10 and obturated with 1 of the previously mentioned sealers mixed with trace amounts of rhodamine using either the CW or SC technique. Teeth were sectioned at 1 mm and 5 mm from the apex and examined under a confocal laser microscope. The percentage of sealer penetration and the maximum sealer penetration were measured. RESULTS: The tricalcium silicate sealers penetrated tubules as deep as 2000 µm (2 mm). The percentage of sealer penetration was much higher 5 mm from the apex, with many specimens having 100% penetration for both SC and warm vertical techniques. MTA Fillapex, a resin-based sealer with less than 20% MTA particles, had significantly greater tubule penetration with a warm vertical technique versus the SC technique at the 1-mm level. CONCLUSIONS: Within the limitations of this study, the CW and SC techniques produced similar tubule penetration at both the 1-mm and the 5-mm level with the tricalcium silicate sealers BC Sealer, QuickSet2, and NeoMTA Plus.

Comparación in vitro de la difusión iónica de pastas de hidróxido de calcio usadas como medicación intraconducto con diferentes vehículos / In vitro comparison of ionic diffusion of calcium hidroxide pastes used as intracanal medication with different vehicles

La medicación intraconducto consiste en la colocación de un medicamento en el interior del conducto radicular. En la actualidad, la pasta de hidróxido de calcio es la más utilizada. Su mecanismo de acción se basa en la disociación de iones oxhidrilos y calcio, responsables de efectos antibacterianos y de reparación tisular. El objetivo de este trabajo fue comparar la difusión de iones calcio y oxhidrilos de la pasta de hidróxido de calcio en el tiempo, utilizando como vehículo agua tridestilada, polietilenglicol y gel de aloe vera. Se utilizaron 45 caninos, se realizó radiografías preoperatorias, aperturas, determinación de la longitud de trabajo para la preparación biomecánica de los conductos. Se rellenaron los especímenes con cada una de las pastas tomando radiografías postoperatorias. Se colocaron las muestras en un medio de análisis almacenándolas en estufa a 37ºC durante 3, 24, 72,168 y 336 horas. Se realizó por triplicado la determinación del pH con pH-metro Metrohm 692 y de la concentración de calcio total utilizando el método espectrofotométrico (reacción del calcio con cresolftaleína complexona a pH 11). Los datos se analizaron estadísticamente por medio de ANOVA aplicando el test de LSD (alfa= 0,05). El comportamiento difusional de las pastas alcalinas con vehículo agua tridestilada y polietilenglicol fue similar en las primeras etapas de experimentación y difirió en las etapas finales. La pasta alcalina con gel de aloe vera mostró un comportamiento de iones oxhidrilos diferente en las primeras etapas de experimentación, el comportamiento de iones calcio fue similar hasta las 168 horas

The intracanal medication consists in placing a medication inside the root canal. At present, the calcium hydroxide paste is most often used. Its mechanism of action is based on the dissociation of calcium ions and hydroxyls responsible for antibacterial effects and tissue repair. The aim of this study was to compare the diffusion of calcium ions and hydroxyls of calcium hydroxide paste in time, using triple distilled water as a vehicle, polietilienglicol and aloe vera gel. 45 canine teeth were used, was performed preoperative radiographs, openings, determining the working length to the biomechanical canal preparation. Specimens with each of the pastes were filled and postoperative radiographs were taken. The samples were placed in a medium of analysis were stored in an oven at 37 ° C for 3, 24, 72,168 and 336 hours. Was performed triplicate pH determination with Metrohm 692 pH meter and the total calcium concentration using the spectrophotometric method (reaction of calcium with cresolphthalein complexone to pH 11). The data were statistically analyzed by ANOVA using the LSD test ( = 0.05). The diffusional behavior of alkaline pasta with water tridistilled -polyethylene vehicle was similar in the initial stages of experiment and in the final stages different. The alkaline paste with aloe vera gel showed a different behavior of hydroxyls ions in the early stages of testing, the behavior of calcium ions was similar up the 168 h

Evaluación clínica y radiográfica del tratamiento de una reabsorción dentinaria interna. Control a los 21 años / Clinical and radiographic evaluation of a internal root resorption treatment. 21-years follow-up

La reabsorción radicular interna es una condición inflamatoria en dientes permanentes que se detecta durante una evaluación radiográfica. La terapia no quirúrgica del conducto radicular es el tratamiento de elección. El siguiente caso clínico describe el tratamiento endodóntico en dos incisivos centrales superiores afectados por extensa reabsorción radicular interna en un paciente joven sin antecedentes de trauma dental. El control radiográfico a los 21 años demostró la manutención de la salud de los tejidos periradiculares y una resolución satisfactoria del caso clínico (AU)

Internal root resorption is an inflammatory condition in permanent teeth that is detected during radiographic evaluation. Nonsurgical root canal therapy is the proposed treatment. The following case report describes the endodontic treatment on maxillary central incisors affected by extensive internal root resorption in a young patient without history of dental trauma. The follow-up radiograph at 21-years showed the maintenance of health of the periradicular tissues and a satisfactory resolution of the case satisfactory resolution of the case (AU)

Effects of intracanal mineral trioxide aggregate and calcium hydroxide during four weeks on pH changes in simulated root surface resorption defects: an in vitro study using matched pairs of human teeth.

INTRODUCTION: Diffusion of hydroxyl ions from intracanal calcium hydroxide (CH) through dentin is used to arrest external inflammatory root resorption. However, long-term and short-term CH placement has been associated with an increased risk of root fracture. Intracanal mineral trioxide aggregate (MTA) might provide an alternative to CH as a source of hydroxyl ions. This in vitro study compared the effects of intracanal MTA and CH on hydroxyl ion diffusion through dentin by measuring pH changes over time in simulated root surface resorption defects prepared in matched pairs of teeth; the null hypothesis tested was that there is no difference. METHODS: Root surface cavities were prepared 5 mm from the apex in extracted human permanent anterior teeth (21 matched pairs) and 7 additional teeth (controls). Root canals were instrumented to size 50/.04 and filled with either tooth-colored MTA (ProRoot) or CH (UltraCal XS); control teeth were filled with saline. The pH in root surface cavities was measured at 3 hours, 24 hours, 1 week, 2 weeks, 3 weeks, and 4 weeks. RESULTS: In controls, pH readings did not differ significantly during the 4 weeks (P > .05, repeated-measures analysis of variance [ANOVA]). For the experimental intragroup effects, significant pH changes occurred over time in the MTA group (P = .005, repeated-measures ANOVA) and the CH group (P < .0001). For the experimental intergroup effects, the overall mean pH was higher in the MTA group (8.66; standard error [SE], 0.07) compared with the CH group (8.46; SE, 0.07) (P = .014, paired t test). At 4 weeks pH was higher in the MTA group (8.30; SE, 0.16) compared with the CH group (7.90; SE, 0.11) (P = .011); at all other time points intergroup differences were insignificant. The null hypothesis was rejected. CONCLUSIONS: Intracanal MTA and CH groups differed in their overall effect on pH measured in simulated root surface resorption defects. At 4 weeks intracanal placement of MTA compared with CH resulted in a small but significantly higher pH.

Reacción del tejido conectivo de ratas a dos selladores endodónticos a base de resinas / Reaction of the rat conective tissue by two base don resin endodontic sealer

El propósito de este estudio fue evaluar la respuesta del tejido conectivo de ratas, ante dos selladores endodónticos a base resinas, el Abseal de la firma Meta Biomed Co Corea y AH36 de la firma De Trey/Dnstply-Maillefer EE.UU. Se utilizaron 40 ratas Wistar hembras de aproximadamente 150-200gr de peso. Los materiales fueron llevados en tubos de silicona e implantados en tejido celular subcutáneo de ratas. Para el control negativo se utilizaron tubos vacíos. Los animales fueron sacrificados en grupos de 10 a lso 7, 14,30 y 60 días. Se evaluó cualitativa y cuantitativamente la reacción inflamatoria producida por los implantes bajo microscopia óptica. Los resultados mostraron que el área de reacción inflamatoria en los tubos obturados con Adseal fue menor en los controles de 7,14 y 30 días. A los 60 días ambos materiales mostraron aéreas mínimas de inflación (AU)

The aim or this study was to evaluate the inflammatory reaction of the connective tissue of rats produced by two resin based endodontic sealers: Adseal (MetaBiomed Korea) and AH26 (De Trey/Densply-Zurich). For this study two groups of forty Wstar rats, 150-200 grams body weight, were employed. Silicons tubes were filled with the sealers and implanted in cellular subcutaneous tissue in rats. Emply tubes were used as negative control. They were then sacrified in groups of ten edach at 7, 14.30 and 60 days. The inflammatory reaction qualitative and quantitative was evaluated under optic microscopy. The results showed smaller inflammatory areas around Adseal tubes at 7,14, and 30 days. On the 60 days tests both materials showed minimal inflammatory areas (AU)

Synthesis and characterization of a new dimethacrylate monomer based on 5,50-bis(4-hydroxylphenyl)-hexahydro-4,7-methanoindan for root canal sealer application.

In this study, a new dimethacrylate monomer 5,5'-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]-hexahydro-4,7-methan-oindan (5,5'-BHMPHM) with molecular weight of 640 and large molecular volume was designed and synthesized. The structure of monomer 5,5'-BHMPHM was confirmed by FT-IR, 1H-NMR and elemental analysis. Degree of double bond conversion, volume shrinkage, contact angle, water sorption and solubility, diffusion coefficient value, flexure strength and modulus of 5,5'-BHMPHM/tri(ethylene glycol) dimethacrylate (TEGDMA) based resin were measured. 2,2-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]-propane(Bis-GMA)/TEGDMA based resin was used as reference. The result illustrated that the double bond conversion, polymerization shrinkage, and diffusion coefficient value of 5,5'-BHMPHM/TEGDMA based resin were significantly lower than that of Bis-GMA/TEGDMA based resin (P<0.05). Water sorption, solubility, flexure strength and modulus of 5,5'-BHMPHM/TEGDMA based resin were higher than that of Bis-GMA/TEGDMA based resin (P<0.05). There was no statistical difference between 5,5'-BHMPHM/TEGDMA based resin and Bis-GMA/TEGDMA based resin in contact angle (P>0.05).

Evaluation of the diffusion capacity of calcium hydroxide pastes through the dentinal tubules.

This study aimed to evaluate the diffusion capacity of calcium hydroxide pastes with different vehicles through dentinal tubules. The study was conducted on 60 extracted single-rooted human teeth whose crowns had been removed. The root canals were instrumented and divided into 4 groups according to the vehicle of the calcium hydroxide paste: Group I - distilled water; Group II - propylene glycol; Group III - 0.2% chlorhexidine; Group IV - 2% chlorhexidine. After placement of the root canal dressings, the teeth were sealed and placed in flasks containing deionized water. After 1, 2, 7, 15, 30, 45 and 60 days, the pH of the water was measured to determine the diffusion of calcium hydroxide through the dentinal tubules. The data were recorded and statistically compared by the Tukey test. The results showed that all pastes presented a similar diffusion capacity through dentin. Group IV did not present difference compared to group I. Group II presented difference compared to the other groups, as did Group III. In conclusion, groups I and IV presented a better diffusion capacity through dentin than groups II and III; 2% chlorhexidine can be used as a vehicle in calcium hydroxide pastes.

In vitro pharmacodynamic activities of root canal sealers on Enterococcus faecalis.

AIM: The aim of this study was to evaluate the antimicrobial efficiency of different root canal sealers on Enterococcus faecalis (E. Faecalis) at different time intervals. METHODS AND MATERIALS: All sealers used were mixed according to the manufacturers' instructions then 75 mg of each sealer was added to different sterile tubes and evaluated at 20 minutes, 24 hours, 7 days, and 30 days. A time-kill assay (TKA) was used to determine the antimicrobial efficiency of the sealers. RESULTS: AH Plus and MCS were found to be bactericidal at 20 minutes and 24 hours, but only MCS was bactericidal at the seventh and thirtieth days. Epiphany and Sealapex were found to be bacteriostatic at the seventh and thirtieth days but indifferent at 20 minutes and 24-hours. MCS and AH Plus were both found to be bactericidal in freshly mixed samples, but only MCS was bactericidal at longer time periods. Epiphany Sealer and Sealapex were found to be bacteriostatic at longer time periods but indifferent at 20 minutes and 24 hours. CONCLUSION: The antibacterial effect of MCS was greater than the other sealers evaluated. CLINICAL SIGNIFICANCE: Sealers containing eugenol and epoxy resin might be preferable due to their antibacterial effect.

Evaluation of the diffusion capacity of calcium hydroxide pastes through the dentinal tubules

This study aimed to evaluate the diffusion capacity of calcium hydroxide pastes with different vehicles through dentinal tubules. The study was conducted on 60 extracted single-rooted human teeth whose crowns had been removed. The root canals were instrumented and divided into 4 groups according to the vehicle of the calcium hydroxide paste: Group I - distilled water; Group II - propylene glycol; Group III - 0.2 percent chlorhexidine; Group IV - 2 percent chlorhexidine. After placement of the root canal dressings, the teeth were sealed and placed in flasks containing deionized water. After 1, 2, 7, 15, 30, 45 and 60 days, the pH of the water was measured to determine the diffusion of calcium hydroxide through the dentinal tubules. The data were recorded and statistically compared by the Tukey test. The results showed that all pastes presented a similar diffusion capacity through dentin. Group IV did not present difference compared to group I. Group II presented difference compared to the other groups, as did Group III. In conclusion, groups I and IV presented a better diffusion capacity through dentin than groups II and III; 2 percent chlorhexidine can be used as a vehicle in calcium hydroxide pastes.

Calcium ion diffusion from mineral trioxide aggregate through simulated root resorption defects.

The purpose of this study was to investigate the diffusion of calcium ions (Ca+2) through exposed dentinal tubules following intracanal application of mineral trioxide aggregate (MTA). Fifty-two single-rooted teeth were instrumented using 2.5% sodium hypochlorite for irrigation between each file size. Thereafter, standardized defects were created on the root surfaces so as to mimic external root resorption. The root canals and external defects received a final irrigation of 17% ethylenediaminetetraacetic acid and distilled water. MTA powder was then mixed with saline and placed into the canals. All root surfaces except the cavities were sealed with two coats of varnish. Teeth with unfilled canals (n = 26) served as controls. The teeth were immersed in saline after which the release of Ca+2 from the defects into the saline was measured at 1, 3, 7, 14, and 28 days. The results showed diffusion of Ca+2 through the defects in the dentin in MTA-filled roots with a significant increase in concentration within time.

The penetration of RealSeal primer and Tubliseal into root canal dentinal tubules: a confocal microscopic study.

AIM: To compare penetration depth into dentinal tubules of RealSeal with that of a well-established endodontic sealer (Tubliseal) by means of confocal microscopy. METHODOLOGY: Twenty sound extracted, single-rooted premolars were selected. Following completion of root canal instrumentation, the teeth were divided into two groups using a stratified sampling method, ranking teeth according to size. In group 1, 10 teeth were filled with Gutta-percha and Tubliseal using cold lateral condensation. In group 2, 10 teeth were filled with RealSeal. Both sealers were labelled with Rhodamine B dye. The teeth were sectioned parallel to their long axis resulting in 20 specimens per group. Confocal microscopy was used to assess the penetration depths of the sealers at three sites for each specimen (coronal, middle and apical). Data were analysed statistically using Stata Release 9.1. RESULTS: The penetration depth of RealSeal in each one of the thirds of the root canal was found to be higher than that of Tubliseal (P < 0.05). The penetration depths of the two sealers was found to be significantly different (P = 0.001). The mean penetration value for the RealSeal group was 908.8 microm whereas the mean value for the Tubliseal group was 139.5 microm. CONCLUSIONS: The penetration depth of RealSeal into the root dentinal tubules is significantly greater than that of Tubliseal.

Susceptibility of a polycaprolactone-based root canal filling material to degradation. Evidence of biodegradation from a simulated field test.

PURPOSE: To examine if Resilon, a polycaprolactone-based root filling material, was susceptible to microbial biodegradation by using a simulated field test that consisted of incubating the material in wet dental sludge under mesophilic and aerobic conditions. METHODS: Pressed disks prepared from Resilon, polycaprolactone (positive control) and gutta-percha (negative control) were incubated in wet dental sludge for up to 4 months and examined for topographical changes using scanning electron microscopy. RESULTS: Gutta-percha exhibited minimal changes in surface integrity, while polycaprolactone and Resilon exhibited severe surface pitting and erosion. In the latter, disappearance of the polymer matrix was accompanied by exposure of mineral and bioactive glass fillers. Bacteria and hyphae-like structures were present on the disk surfaces.