Effects of different irrigation activation methods on root canal treatment of primary teeth.

There is currently a lack of research on the application of newly developed irrigation techniques in root canal treatment of primary teeth. This study aimed to evaluate the effects of various irrigation activation techniques on two key parameters: apical debris extrusion (ADE) and dentinal tubule penetration depth (DTPD) of the root canal filling material. A total of 96 primary mandibular second molars were randomly divided into 4 groups: Group 1-Conventional Needle Irrigation (CNI), Group 2-XP-Endo Finisher (XPF), Group 3-EndoActivator (EA), and Group 4-Passive Ultrasonic Irrigation (PUI). In all groups, the One Reci single-file system was used for root canal preparation. For ADE measurement, each group was rinsed with distilled water. For DTPD assessment, sodium hypochlorite (NaOCl) was applied. ADE quantification was performed by collecting debris in pre-weighed Eppendorf tubes. A combination of fluorescent dye and root canal filling material (DiaPex Plus) was used for root canal filling. In order to examine DTPD, horizontal cross-sections of the coronal and apical regions of the teeth were taken with a thickness of 1 mm. The maximum and mean DTPD was examined by confocal laser scanning microscopy. Data were analyzed using the Kruskal-Wallis, One-way ANOVA, and Mann-Whitney U tests (p = 0.05). As a result, PUI had the highest mean ADE and CNI had the lowest mean ADE, while CNI had the highest mean DTPD in both the coronal and apical regions, whereas PUI had the lowest mean DTPD in the coronal region, and EA had the lowest mean DTPD in the apical region. There were no statistically significant differences in DTPD and ADE among the four groups. Comparing intragroup maximum DTPD across all groups, it was significantly higher in the coronal region than in the apical region (p < 0.05). ADE and DTPD of root canal filling materials in primary teeth did not differ significantly among CNI, XPF, EA and PUI irrigation activation techniques.

Antimicrobial action and cytotoxicity of hypochlorous acid obtained from an innovative electrolytic device - An in vitro study.

OBJECTIVE: This study evaluated the antimicrobial effect and cytotoxicity of hypochlorous acid(HClO) obtained from an innovative electrolytic device. DESIGN: The root canals of fifty extracted human teeth were inoculated with Enterococcus faecalis and divided into 5 groups (n = 10): DW (control); 2% chlorhexidine gel(CHX); 2.5% sodium hypochlorite(NaOCl); 250 ppm HClO and 500 ppm HClO. The counting of colony forming units evaluated the decontamination potential of each group. Cytotoxicity was evaluated after inoculation of tested protocols in fibroblastic cells for 3 min, calculating the cell viability. Specific statistical analysis was performed (α = 5%). RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences from each other (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences from each other (p < 0.05). CONCLUSIONS: It could be concluded that HClO presented high antimicrobial activity and low cytotoxicity at both tested concentrations.

Comparative Analysis of AH Plus Bond Strength to Root Canal Dentin and Adhesive Interface Quality after Calcium Hydroxide Removal using Different Irrigation Protocols.

INTRODUCTION: To evaluate the push-out bond strength (POBS) of AH Plus sealer to root dentin and the adhesive interface quality after calcium hydroxide (Ca(OH)2) intracanal dressing removal with different final irrigation protocols. METHOD: After root canal instrumentation and irrigation, 40 root canals were filled with Ca(OH)2 and sealed. After 14 days, the specimens were randomly distributed according to the irrigation protocols for Ca(OH)2 removal (n = 10): GH2O (control) - distilled water; GNaOCl - 1% NaOCl; GEDTA - 17% EDTA; GEDTA + NaOCl - 17% EDTA + 1% NaOCl. The root canals were filled with AH Plus sealer and gutta-percha. After 7 days, the roots were sectioned into dentin slices and submitted to POBS test and analysis of the adhesive interface under scanning electron microscope. The POBS data were statistically evaluated (analysis of variance and Tukey test). The Kruskal-Wallis and Mann-Whitney tests were used to analyze the adhesive interface (α = 0.05). RESULTS: GH2O, GNaOCl, and GEDTA + NaOCl had similar POBS values, with higher values on the apical third, in comparison with other thirds (P < .05). A homogeneous and free-of-gaps adhesive interface was observed for GH2O, GNaOCl, and GEDTA + NaOCl, with difference between GH2O and GEDTA (P < .05). GH2O and GEDTA + NaOCl presented higher sealer tags formation (P < .05). CONCLUSION: The final rinse with EDTA for Ca(OH)2 dressing removal had a negative effect on the POBS of the filling material to root dentin. The use of EDTA followed by NaOCl had results similar to the distilled water, providing uniform and free-of-gaps adhesive interface, and a higher number of sealer tags.

Comparative evaluation of Sapindus Mukorossi extract with 17% EDTA on smear layer removal in various parts of the tooth root.

OBJECTIVES: This study aimed to compare the effectiveness of an experimental root canal irrigant and 17% Ethylene-di-amine tetra acetic acid for removal of the smear layer in the coronal, middle and apical portions of the root canal. MATERIALS AND METHODS: Ninety human single rooted maxillary and mandibular teeth were selected for this study. The teeth were randomly divided into two experimental groups and one control group as follows: Group A (Ethanolic extract of Sapindus Mukorossi), Group B (17% EDTA), and Group C (Distilled water). The root canals of all three groups were prepared with stainless steel K-files by means of the standard step-back technique and irrigated with 5.25% sodium hypo chloride. The teeth were decoronated, following the irrigation and divided longitudinally into two-halves and visualized using scanning electron microscope (SEM) for the amount of smear layer present utilizing the three-point score system. The observations were noted both before and after the treatment. Nonparametric tests were applied for the comparison and p-value ⩽ 0.05 was considered as statistically significant. RESULTS: It was evident from that smear layer was completely removed in coronal portion of 27 out of 30 teeth in-group A. For middle and apical areas of group A, 24 and 19 teeth showed complete smear layer removal. In-group B it was found that there were 24, 21, and 3 teeth at coronal, middle and apical, areas respectively where smear layer were completely absent. Intra group comparison showed a significant difference (p = 0.002) in smear layer removal was found for group A at coronal, middle and apical thirds. Similarly, a significant difference (p = 0.001) was also found for group B; however heavy smear layer was found among the three parts of the canal for group C. CONCLUSIONS: Ethanolic extract of Sapindus Mukorossi have higher effectiveness in removing the smear layer from the root canal in comparison to 17% EDTA.

Impact of photodynamic therapy on the marginal adaptation of Biodentine used as root-end filling material.

BACKGROUND: The marginal adaptation of root-end filling materials and the effective antibacterial control in a surgical site are crucial for the successful outcome of endodontic surgery. OBJECTIVE: This study aimed to evaluate the effect of retrograde application of photodynamic therapy on the marginal adaptation of Biodentine used as a root-end filling material. METHODS: Twenty single-rooted anterior teeth were selected, instrumented and obturated with gutta-percha and AH Plus. The apical 3 mm of the roots were resected and root-end cavities were prepared with an ultrasonic retro-tip. The teeth were randomly divided into two groups (n = 10). In the first group, photodynamic therapy (PDT) was applied in the retrograde cavity prior to the root-end filling. In the second group retro cavity was filled without PDT. All specimens were obturated with Biodentine and afterwards sectioned longitudinally. The gap width at the material-dentin interface was measured using a scanning electron microscope. The results were statistically analyzed. RESULTS: The produced gap width by Biodentine/PDT was 3.85 µm versus 2.68 µm in the Biodentine control group with significant differences in-between. CONCLUSION: Under the conditions of this study, PDT has a negative effect on the marginal adaptation of Biodentine used as root-end filling material.

Effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots / Efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar raíces debilitadas

Background: This study evaluated the effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots. Material and Methods: Sixty-four roots of extracted human maxillary canines were weakened, prepared and filled with two different endodontic sealers (Endofill and AH Plus). In half of the sample, set aside for each respective sealer, excess filling material was cleaned. In the other half, the weakened areas were not cleaned, and the excess of sealer was spread on the intraradicular dentin. Intentionally worn areas inside each root were restored with a microhybrid light-cure composite resin (Z100) to reinforce them, with and without acid etching. Prefabricated metal posts were fixed with a dual resin cement (RelyX ARC), and the specimens were submitted to a pull-out test. Statistical analysis was performed by means of Shapiro-Wilk, analysis of variance (one-way ANOVA) and Tukey-Kramer tests (p<0.05). Results: The groups filled with Endofill (GI, GII, GIII, GIV) had the lowest bond strength values, which were similar among each other (p>0.05).The greatest bond strength values were observed in roots filled with AH Plus (GV, GVI, GVII, GVIII), mainly without cleaning of the weakened areas, and followed by acid etching (GVII), and also with cleaning of the weakened areas, however, with no acid etching (GVI) (p<0.05). Conclusion: The greatest bond strength values were observed in roots filled with AH Plus; (1) without cleaning of the weakened areas and with acid etching, and; (2) with cleaning of the weakened areas, but without acid etching.

Antecedentes: este estudio evaluó los efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar las raíces debilitadas. Material y Métodos: Sesenta y cuatro raíces de caninos maxilares humanos extraídos fueron debilitadas, preparadas y rellenadas con dos selladores endodónticos diferentes (Endofill y AH Plus). En la mitad de la muestra, reservada para cada sellador respectivo, se limpió el exceso de material de relleno. En la otra mitad, las áreas debilitadas no se limpiaron y el exceso de sellador se esparció sobre la dentina intrarradicular. Las áreas desgastadas intencionalmente dentro de cada raíz se restauraron con una resina compuesta fotopolimerizable microhíbrida (Z100) para reforzarlas, con y sin grabado ácido. Los postes metálicos prefabricados se fijaron con un cemento de resina dual (RelyX ARC) y los especímenes se sometieron a una prueba de extracción. El análisis estadístico se realizó mediante Shapiro-Wilk, análisis de varianza (ANOVA de una vía) y pruebas de Tukey-Kramer (p<0,05). Resultados: Los grupos rellenos con Endofill (GI, GII, GIII, GIV) presentaron los valores más bajos de fuerza de unión, los cuales fueron similares entre sí (p>0,05). Los mayores valores de fuerza de unión se observaron en raíces rellenas con AH Plus (GV, GVI, GVII, GVIII), principalmente sin limpieza de las áreas debilitadas, seguido de grabado ácido (GVII), y también con limpieza de las áreas debilitadas aunque sin grabado ácido (GVI) (p<0.05). Conclusión: Los mayores valores de fuerza de unión se observaron en las raíces rellenas con AH Plus; (1) sin limpieza de las áreas debilitadas y con grabado ácido, y; (2) con limpieza de las áreas debilitadas, pero sin grabado ácido.

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.

Antimicrobial Effect of Calcium Hydroxide Combined with Electrolyzed Superoxidized Solution at Neutral pH on Enterococcus faecalis Growth.

OBJECTIVE: To evaluate the effect of the combination of calcium hydroxide (Ca(OH)2) and a novel electrolyzed superoxidized solution at neutral pH, known as OxOral® on Enterococcus faecalis growth in root canals. METHODS: Sixty human teeth were used, from which root canals were infected and randomly divided into the following treatment groups: saline solution, saline solution plus Ca(OH)2, OxOral®, and OxOral® plus Ca(OH)2. RESULTS: A permanent reduction in bacterial growth was observed at days 1, 6, 12, and 18 after OxOral® plus Ca(OH)2 treatment from 4.4 ± 0.074 log10 CFU/mL to 0.0 ± 0.001 log10 CFU/mL. In addition, alkaline conditions maintenance was observed from application time (pH = 12.2 ± 0.033) to 18 d posttreatment (pH = 12.6 ± 0.083). CONCLUSION: The combination of OxOral® and Ca(OH)2 provides an alkaline pH and inhibits E. faecalis growth into the root canals. Our study opens the possibility for further research on the use of OxOral® in endodontic therapy.

Evaluation of the anti-biofilm effect of poloxamer-based thermoreversible gel of silver nanoparticles as a potential medication for root canal therapy.

The purpose of this study was to design silver nanoparticles (AgNPs) poloxamer thermoreversible gel (AgNPs-PL) and investigate whether this gel could provide sustained antibacterial activity against Enterococcus faecalis (E. faecalis) in the root canal. The gels fabricated were characterized in terms of gelatin temperature, particle size, in-vitro Ag+ release, and elemental content. Cytotoxicity of AgNPs-PL on primary human periodontal ligament fibroblasts (HPDLFs) was examined by CCK-8 assay. Characterization of AgNPs-PL gel revealed that it contained particles existing as large clumps/fused aggregates of different shapes, with a mean diameter of 21.624 ± 14.689 nm, exhibited sustained release of Ag+ for 9 days, and non-toxic to HPDLFs at a low dose (4-32 µg/mL) through 24, 48, and 72 h exposures. The antibacterial effect of 16 and 32 µg/mL concentrations of AgNPs-PL was compared with blank poloxamer gel (PL) and calcium hydroxide (CH) using three methods: (I) agar counting plate, (II) scanning electron microscope (SEM) observations, and (III) confocal laser scanning microscope (CLSM) analysis. AgNPs-PL at the two doses above was more effective than PL and CH in removing E. faecalis biofilm at 1, 3, 9 days. Thus, AgNPs-PL exhibits strong activity against E. faecalis and is easy to produce, with a continuous release profile of Ag+. AgNPs-PL gel may be a candidate for a new root canal disinfection.

Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal.

To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 µm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and ß-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm-1 band and an increase in the 870 cm-1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.

Root Canal Disinfection Using Highly Effective Aggregation-Induced Emission Photosensitizer.

Root canal (RC) therapy is the primary treatment of dental-pulp and periapical diseases. The mechanical method and chemical irrigation have limitations in RC therapy. Much attention has focused on exploring more controllable and efficacious antimicrobial methods. Although the introduction of photodynamic therapy (PDT) has provided the ideas for RC debridement, the problems of low photosensitive efficiency and nonsignificant germicidal potency of traditional photosensitizers (e.g., methylene blue) have not been solved. Since the concept of "aggregation-induced emission" (AIE) was proposed, optimization of photosensitizers has been boosted considerably. Herein, an AIE photosensitizer, DPA-SCP, with a strong ability to generate singlet oxygen, is proposed for use as an antibacterial application in infected RCs. The antimicrobial activity of DPA-SCP against Enterococcus faecalis suspensions was tested. To explore the antibacterial ability of this photosensitizer against bacterial-biofilm colonization on the inner walls of RCs, we established a model of bacterial biofilm infection. PDT mediated by DPA-SCP had a significant germicidal effect on E. faecalis suspensions and 21-day biofilms in human RCs. PDT mediated by DPA-SCP could achieve efficiency equivalent to that observed using 1% NaOCl, and lead to no significant change in the dentin surface, chemical corrosion, or cytotoxicity.

The use of different adhesive filling material and mass combinations to restore class II cavities under loading and shrinkage effects: a 3D-FEA.

3D tooth models were virtually restored: flowable composite resin + bulk-fill composite (A), glass ionomer cement + bulk-fill composite (B) or adhesive + bulk-fill composite (C). Polymerization shrinkage and masticatory loads were simulated. All models exhibited the highest stress concentration at the enamel-restoration interfaces. A and C showed similar pattern with lower magnitude in A in comparison to C. B showed lower stress in dentine and C the highest cusps displacement. The use of glass ionomer cement or flowable composite resin in combination with a bulk-fill composite improved the biomechanical behavior of deep class II MO cavities.

Development of Chlorhexidine Digluconate and Lippia sidoides Essential Oil Loaded in Microemulsion for Disinfection of Dental Root Canals: Substantivity Profile and Antimicrobial Activity.

The dental intracanal disinfection is crucial to achieve the success of endodontic treatment, avoiding the maintenance of endodontic infections. Chlorhexidine digluconate can act as an irrigating agent for it. However, it can cause tissue irritation in high concentrations. Therefore, combinations with other antimicrobial agents and more efficient therapeutic alternatives are studied, which make it possible to administer drugs more safely and with minimal adverse effects. Thus, the objective of this study was the development of a microemulsion containing chlorhexidine digluconate and essential oil of Lippia sidoides to be used for disinfection of dental root canals and to evaluate its profile of substantivity and antimicrobial activity. The microemulsions were obtained through phase diagrams, using the spontaneous formation method. We completed a physical-chemical characterization and evaluate the stability of the microemulsions, in addition to the substantivity profile in a bovine root dentin model, and in vitro antibacterial effect on Enterococcus faecalis. A method for quantifying chlorhexidine was developed using UV-Vis spectroscopy. The microemulsions showed acid pH, conductivity above 1.3 µScm-1, and dispersion index similar to water. The microemulsions showed antimicrobial inhibition halos similar to the commercial gel conventionally used, but with four times more substantivity to dentinal tissues. Microemulsions were obtained as a therapeutic alternative to formulations available on the market, presenting themselves as a system with great potential for the administration of drugs for disinfection of root canals.

Post preparation: cleanness achieved by different irrigating protocols.

The aim of this study was to evaluate the ability of different irrigation protocols to remove from the walls of the root canal and entrance to dentinal tubules the smear layer produced during preparation for a fiber post. Fifty decoronated human lower premolars were treated endodontically and the apical third of the canal was filled with a single gutta-percha point using warm vertical compaction. Ten millimeters were left free for post preparation, which was done by sequential use of a Largo #1 drill and Exacto #3 pilot drill (Angelus, Brazil), with irrigation with distilled water upon each instrument change. Samples were distributed randomly into 5 groups (n=10). G 1: No irrigation after post preparation. G 2: Distilled water activated for 60 s + distilled water. G 3: 5.25% NaOCl 15 s+ distilled water. G 4: 17% EDTA (Farmadental, Argentina) 60 s + 5.25% NaOCl 15 s + distilled water. G 5: 10% polyacrylic acid (Densell) 15 s + distilled water. Irrigant was activated mechanically with a low-speed conical brush. Roots were then split longitudinally in vestibular-lingual direction. Each surface was observed under SEM in its different thirds. Microphotographs were taken at 150X and 600X magnification and results analyzed statistically using Kruskall Wallis and Friedman tests (p<0.05). The results [mean (standard deviation)] were: for 150X: G1 11.00 (1.33), G2 7.50 (3.13), G3 6.30 (2.58), G4 2.20 (2.80), G5 4.30 (1.50), and for 600X G1 11.40 (0.84), G2 10.00 (1.94), G3 7.70 (3.33), G4 5.80 (3.70), G5 7.20 (2.65). The statistical analysis showed significant differences between irrigants (p<0.05) but not between root thirds (p>0.05). The EDTA+NaOCl combination and polyacrylic acid showed greater capacity to remove the smear layer created during post preparation.

El objetivo del presente trabajo fue evaluar la capacidad de diferentes protocolos de irrigación para remover el barro dentinario de las paredes del conducto y entrada de los túbulos dentinarios, producido durante la preparación para anclaje intarradicular. Se utilizaron 50 premolares inferiores humanos a los cuales se les cortó la corona clínica. Luego se les realizó tratamiento endodóntico y obturación del tercio apical con cono único de conicidad aumentada y compactación vertical caliente. Se dejaron libres 10 mm para la preparación para poste que se realizó utilizando secuencialmente fresa de Largo # 1y fresa piloto Exacto #1(Angelus, Brasil), irrigando a cada cambio de instrumento con agua destilada. Las muestras fueron distribuidas aleatoriamente en 5 grupos (n=10). G 1: No se efectuó ningún lavaje. Los irrigantes fueron activados con cepillo mecánico cónico a baja velocidad. G 2: Agua destilada activada 60 s+ agua destilada G 3: NaOCl al 5,25%, 15 s+ agua destilada. G 4: EDTA al 17% (Farmadental, Argentina) 60 s +NaOCl al 5,25% 15 s , + agua destilada. G 5 : Ácido poliacrílico al 10% ( Densell) 15 s + agua destilada. Posteriormente, las raíces fueron seccionadas longitudinalmente en sentido vestíbulo lingual. Cada superficie fue observada al MEB en sus diferentes tercios. Las micrografías se realizaron a 150 y 600 X y los resultados analizados estadísticamente mediante test de Kruskall Wallis y Friedman (p<0,05), Los resultados [Medias (desviaciones estándar)] fueron: para 150X G1 11,00(1,33), G2 7,50 (3,13), G3 6,30 (2,58), G4 2,20 (2,80), G5 4,30 (1,50) y para 600X G1 11,40 (0,84), G2 10,00 (1,94), G3 7,70 (3,33), G4 5,80 (3,70), G5 7,20 (2,65). El análisis estadístico mostró diferencia significativa entre irrigantes (p<0,05) pero no entre tercios radiculares (p>0,05). La combinación de EDTA+NaOCl y el ácido poliacrílico tendrían mayor capacidad de remoción del barro dentinario creado durante la preparación para poste.

Post preparation: cleanness achieved by different irrigating protocols / Preparación para poste: limpieza lograda por diferentes protocolos de irrigación

ABSTRACT The aim of this study was to evaluate the ability of different irrigation protocols to remove from the walls of the root canal and entrance to dentinal tubules the smear layer produced during preparation for a fiber post. Fifty decoronated human lower premolars were treated endodontically and the apical third of the canal was filled with a single gutta-percha point using warm vertical compaction. Ten millimeters were left free for post preparation, which was done by sequential use of a Largo #1 drill and Exacto #3 pilot drill (Angelus, Brazil), with irrigation with distilled water upon each instrument change. Samples were distributed randomly into 5 groups (n=10). G 1: No irrigation after post preparation. G 2: Distilled water activated for 60 s + distilled water. G 3: 5.25% NaOCl 15 s+ distilled water. G 4: 17% EDTA (Farmadental, Argentina) 60 s + 5.25% NaOCl 15 s + distilled water. G 5: 10% polyacrylic acid (Densell) 15 s + distilled water. Irrigant was activated mechanically with a low-speed conical brush. Roots were then split longitudinally in vestibular-lingual direction. Each surface was observed under SEM in its different thirds. Microphotographs were taken at 150X and 600X magnification and results analyzed statistically using Kruskall Wallis and Friedman tests (p<0.05). The results [mean (standard deviation)] were: for 150X: G1 11.00 (1.33), G2 7.50 (3.13), G3 6.30 (2.58), G4 2.20 (2.80), G5 4.30 (1.50), and for 600X G1 11.40 (0.84), G2 10.00 (1.94), G3 7.70 (3.33), G4 5.80 (3.70), G5 7.20 (2.65). The statistical analysis showed significant differences between irrigants (p<0.05) but not between root thirds (p>>0.05). The EDTA+NaOCl combination and polyacrylic acid showed greater capacity to remove the smear layer created during post preparation.

RESUMEN El objetivo del presente trabajo fue evaluar la capacidad de diferentes protocolos de irrigación para remover el barro dentinario de las paredes del conducto y entrada de los túbulos dentinarios, producido durante la preparación para anclaje intarradicular. Se utilizaron 50 premolares inferiores humanos a los cuales se les cortó la corona clínica. Luego se les realizó tratamiento endodóntico y obturación del tercio apical con cono único de conicidad aumentada y compactación vertical caliente. Se dejaron libres 10 mm para la preparación para poste que se realizó utilizando secuencialmente fresa de Largo # 1y fresa piloto Exacto #1(Angelus, Brasil), irrigando a cada cambio de instrumento con agua destilada. Las muestras fueron distribuidas aleatoriamente en 5 grupos (n=10). G 1: No se efectuó ningún lavaje. Los irrigantes fueron activados con cepillo mecánico cónico a baja velocidad. G 2: Agua destilada activada 60 s+ agua destilada G 3: NaOCl al 5,25%, 15 s+ agua destilada. G 4: EDTA al 17% (Farmadental, Argentina) 60 s +NaOCl al 5,25% 15 s , + agua destilada. G 5 : Ácido poliacrílico al 10% ( Densell) 15 s + agua destilada. Posteriormente, las raíces fueron seccionadas longitudinalmente en sentido vestíbulo lingual. Cada superficie fue observada al MEB en sus diferentes tercios. Las micrografías se realizaron a 150 y 600 X y los resultados analizados estadísticamente mediante test de Kruskall Wallis y Friedman (p<0,05), Los resultados [Medias (desviaciones estándar)] fueron: para 150X G1 11,00(1,33), G2 7,50 (3,13), G3 6,30 (2,58), G4 2,20 (2,80), G5 4,30 (1,50) y para 600X G1 11,40 (0,84), G2 10,00 (1,94), G3 7,70 (3,33), G4 5,80 (3,70), G5 7,20 (2,65). El análisis estadístico mostró diferencia significativa entre irrigantes (p<0,05) pero no entre tercios radiculares (p>0,05). La combinación de EDTA+NaOCl y el ácido poliacrílico tendrían mayor capacidad de remoción del barro dentinario creado durante la preparación para poste.

Comparación de desinfección de diferentes marcas de punta de gutapercha con hipoclorito de sodio / Comparison of disinfection of different brands of gutta-percha tip with sodium hypochlorite

En la terapia endodóncica uno de los principales objetivos es eliminar y prevenir la infección o reinfección del sistema de conductos radiculares y/o los tejidos perirradiculares. Los materiales de obturación utilizados podrían introducir microorganismos a este sistema previamente desinfectado e impedir el éxito del tratamiento. Diversos estudios han demostrado que los conos de gutapercha pueden estar contaminados al ser tomados directamente del empaque, aún sellado y recién abierto. Objetivo: Comparación del grado de desinfección de tres marcas diferentes de puntas de gutapercha. Material y métodos: Es un estudio experimental, comparativo, observacional y de corte transversal. En el cual se analizarán tres marcas diferentes de gutaperchas #35 (Maillefer, Hygienic y Meta-Biomed) para saber qué desinfección hay con el hipoclorito de sodio (NaOCl) al 5.25%. Se llevó a cabo el análisis descriptivo para determinar medidas de tendencia central y medidas de dispersión mediante la prueba estadística de ANOVA p ≤ 0.05. Conclusión: De acuerdo con los resultados de nuestro estudio no se encontró diferencia significativa sobre la marca de gutapercha y el grado de descontaminación después de un minuto de ser sumergidas en hipoclorito de sodio al 5.25% (AU)

In endodontic therapy one of the main objectives is to eliminate and prevent infection or reinfection of the root canal system and/or periradicular tissues. The sealing materials used could introduce microorganisms to this previously disinfected system and impede the success of the treatment. Several studies have shown that gutta-percha cones can be contaminated by being taken directly from the package, still sealed and newly opened. Objective: Comparison of the degree of disinfection of 3 different brands of gutta-percha points. Material and methods: It is an experimental, comparative, observational and cross-sectional study. Where 3 different brands of gutta percha # 35 (Maillefer, Hygienic and Meta-Biomed) will be analyzed to know what disinfection there is with sodium hypochlorite (NaOCl) at 5.25%. The descriptive analysis was carried out to determine measures of central tendency and measures of dispersion through the statistical test of ANOVA p ≤ 0.05. Conclusion: According to the results of our study there is no significant difference on the gutta-percha brand and its decontamination at the moment of being submerged in 5.25% sodium hypochlorite (AU)

Sonic irrigant activation for root canal disinfection: power modes matter!

BACKGROUND: Sonic irrigant activation has gained widespread popularity among general dentists and endodontists alike in recent years. This in vitro study aimed to evaluate the impact of three power modes of a sonic activation device (EDDY) on its antimicrobial effectiveness in infected root canals. METHODS: The root canals of straight, human roots (n = 120) were prepared to size 40/.06. In a short-term infection experiment, the root canals were inoculated with different microbial species for three days. The following irrigation protocols, using 4 ml of normal saline as irrigant, were performed: negative control, manual rinsing, sonic irrigant activation at power modes "low", "medium" and "high". In a second, long-term experiment, testing the same irrigation protocols, inoculation lasted 21 days and sodium hypochlorite was used as irrigant. Sequential infection control samples were assessed using culture assays. The statistical analysis included one-way analysis of variance of log10-scaled counts of colony-forming units (CFU) with post-hoc comparisons using Bonferroni corrections and Chi2 tests (α = 0.05). RESULTS: In the short-term experiment, the sonic irrigation protocols decreased the number of CFUs by 1.88 log10 units compared with the negative control (p < 0.001). The power modes "medium" and "high" achieved the most effective reduction of the microbial load. In the long-term experiment, microbial regrowth occurred after 7 days unless the device was used at its highest power setting. CONCLUSIONS: The power modes of the sonic irrigation device have a significant impact on the effectiveness for endodontic disinfection. The sonic irrigation device should always be used at the highest power setting in order to maximize its antimicrobial effectiveness.

Pretreatment of Root Canal with Photodynamic Therapy Facilitates Adhesion, Viability and Differentiation of Stem Cells of the Apical Papilla.

This study was to test the hypothesis that root canal pretreated with photodynamic therapy (PDT) would promote stem cells from the apical papilla (SCAP) adhesion, proliferation and differentiation without affecting smear layer removal and microhardness of root canal. Standardized root canals were randomized into four groups (n = 30/group): (1) sodium hypochlorite(NaOCl) group, (2) NaOCl + ethylene diaminetetraacetic acid (EDTA) group, (3) NaOCl + PDT group, (4) NaOCl + EDTA + PDT group. After treatments, smear layer removal and microhardness of root canal were evaluated. SCAP with hydroxyapatite-based scaffolds were seeded into root canals for 7 days. SCAP adhesion was observed by scanning electron microscope (SEM), and viable cells were calculated by CellTiter-Glo Luminescent kit. Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) expression of SCAP were evaluated by Quantitative Reverse Transcriptase-Polymerase Chain Reaction. There was no significant difference in the smear layer removal and microhardness of root dentin between the groups with and without PDT treatment (P > 0.05). SCAP with elongated cytoplasmic processes and cell-cell contact were observed on the dentin surfaces treated with PDT. Elevated cell viability, PDGF and VEGF expression were found in root canal treated with PDT (P < 0.05). Under the experimental conditions, PDT could provide positive microenvironment for SCAP growth.

Effect of different laser types on bonding strength of CAD/CAM-customized zirconia post to root canal dentin: an experimental study.

In clinical dentistry, the strength of bonding zirconia posts to root canal dentinal walls currently needs enhancement, and laser application can be an important contribution owing to its features that accommodate adjustable modifications on dental materials. Herein, the effect of different laser treatments applied to dentin surfaces on the strength of bonding zirconia posts to root canal dentinal walls is evaluated by using the pull-out bond strength test in a laboratory setting. A total of 40 single-rooted permanent mandibular premolar teeth that were freshly extracted were used here. The root canal preparation steps were performed using the crown-down technique. Custom-made zirconia posts were produced using CAD/CAM technology. Prior to the application of resin cement, the internal surfaces of the root canals were irradiated using Nd:YAG, Er:YAG, and KTP lasers. Pull-out tests were performed on each specimen by using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were used to compare the pull-out bond strength data. The bond strengths of the laser-treated specimens were greater than those of the untreated controls (p < 0.05). While the value of the pull-out bond strength after Nd:YAG laser treatment was significantly higher than the values obtained after the applications of the Er:YAG and KTP lasers (p < 0.05), the pull-out bond strength after Er:YAG laser treatment was considerably greater than that after KTP laser treatment (p < 0.05). The bond strength between the root canal dentin and the CAD/CAM custom-made zirconia post was improved upon using all the laser modalities in current laboratory settings, among which, application of the Nd:YAG laser was the most successful.

The effects of various irrigation protocols on root canal wall adaptation and apical microleakage in primary teeth.

Objective: The objective of this study is to evaluate the wall adaptation and apical microleakage values following the application of various irrigation protocols in primary teeth.Material and methods: For the two parts of the study, extracted upper incisor primary teeth were randomly included to the 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl and 0.9% physiological saline (PS) groups. Canal wall adaptation and apical microleakage were assessed by scanning electron microscopy (SEM) and stereomicroscope, respectively.Results: 6% CA + 1% NaOCl group was found to be the most successful irrigation protocol in providing strong canal wall adaptation and less apical microleakage, followed by 10% EDTA +1% NaOCl. 6% CA +1% NaOCl was significantly superior regarding apical microleakage (p < .05).Conclusions: Due to the ability to provide appropriate changes in the root canal walls to make a well-adapted and leak-proof canal filling, 6% CA + 1% NaOCl can be recommended as an irrigation protocol in primary teeth.