α-IRAK-4 Suppresses the Activation of RANK/RANKL Pathway on Macrophages Exposed to Endodontic Microorganisms.

Periapical lesions are common pathologies affecting the alveolar bone, often initiated by intraradicular lesions resulting from microbial exposure to dental pulp. These microorganisms trigger inflammatory and immune responses. When endodontic treatment fails to eliminate the infection, periapical lesions persist, leading to bone loss. The RANK/RANKL/OPG pathway plays a crucial role in both the formation and the destruction of the bone. In this study, the objective was to inhibit the RANK/RANKL pathway in vitro within exposed Thp-1 macrophages to endodontic microorganisms, specifically Enterococcus faecalis, which was isolated from root canals of 20 patients with endodontic secondary/persistent infection, symptomatic and asymptomatic, and utilizing an α-IRAK-4 inhibitor, we introduced endodontic microorganisms and/or lipoteichoic acid from Streptococcus spp. to cellular cultures in a culture plate, containing thp-1 cells and/or PBMC from patients with apical periodontitis. Subsequently, we assessed the percentages of RANK+, RANKL+, and OPG+ cells through flow cytometry and measured the levels of several inflammatory cytokines (IL-1ß, TNF-α, IL-6, IL-8, IL-10, and IL-12p70) in the cellular culture supernatant through a CBA kit and performed analysis by flow cytometry. A significant difference was observed in the percentages of RANK+RANKL+, OPG+ RANKL+ cells in thp-1 cells and PBMCs from patients with apical periodontitis. The findings revealed significant differences in the percentages of the evaluated cells, highlighting the novel role of the IRAK-4 inhibitor in addressing this oral pathology, apical periodontitis, where bone destruction is observed.

Increased IL-12p70 and IL-8 Produced by Monocytes in Response to Streptococcus spp. and Actinomyces spp. Causals of Endodontic Primary Infections.

We sought to evaluate the effect of endodontic-causative microorganisms of primary infections on mononuclear cells such as CD14+, CD4+, CD8+, CD19+ and Tregs Foxp3+. Facultative anaerobic microorganisms were isolated from radicular conducts and peripheral blood samples, which were taken from patients with primary infections. Cellular cultures were performed with peripheral blood mononuclear cells (PBMC) with and without Actinomyces spp. and Streptococcus spp. during 48, 72, and 96 h of contact in culture (concentration 5 × 105 cells/well) in a round plate bound with 48 wells. Later, PBMC was collected for analysis by flow cytometry, with the monoclonal antibodies αCD14, αCD4, αCD8, αCD19 and αFoxp3, and acquired using an FACSCanto II cytometer. The supernatant of cellular cultures was analyzed for the quantification of inflammatory cytokines. Data analysis was performed in FlowJo v10.8.2 and FCAPArray software, and statistical analysis was performed using GraphPad v5.0. software. We observed an increase in the percentage of CD14+ cells in patients at different hours of cellular culture in the presence of both Actinomyces spp. and Streptococcus spp. microorganisms, compared to healthy controls. This study demonstrates the role played by the innate immune system in the pathogeny of endodontic primary infections, explaining the effects that generate the more common microorganisms in this oral pathology.

Root canal microorganisms and their antibiotic susceptibility in patients with persistent endodontic infections, with and without clinical symptoms.

Secondary/persistent infections are present in teeth with previous root canal treatment, and a great variety of anaerobic microorganisms has been observed in these infections. The antibiotics prescription is occasional; however, in some cases, it is essential, particularly when the general health condition of the patient is compromised. The aims of this study were to identify the associated microorganisms in diagnosis of persistent or secondary apical periodontitis and to evaluate the susceptibility level to the antibiotics most used. Fifteen patients with persistent or secondary apical periodontitis requiring endodontic re-treatment were included. Microbiological samples were taken from the root canals and incubated in thioglycollate under anaerobic conditions. Anaerobic CDC agar (formulated by the Center for Disease Control and Prevention) was employed as a culture medium and the microorganisms were identified using the API system. The microorganisms were subjected to antibiograms with three different antibiotics. Twenty-six microorganisms were identified, the most common genus was Enterococcus (26.8%), Streptococcus (19.22%), Aerococcus (19.1%), and Clostridium (11.4%). 48% of them were susceptible to amoxicillin, with 28% of resistance. For clavulanic acid/amoxicillin, the susceptibility occurred in 32%, with 28% of resistance; and for clindamycin, the susceptibility was present in 40%, with 52% of resistance. The most frequently detected associated microorganism for secondary infections was genus Enterococcus, which exhibited high resistance to the studied antibiotics.

Aerobic and anaerobic microorganisms and antibiotic sensitivity of odontogenic maxillofacial infections.

This study aimed to identify the aerobic and anaerobic causal microorganisms of odontogenic infections and their antibiotic sensitivity. Purulent exudates were taken from patients with odontogenic infections by transdermal puncture, and aerobic and anaerobic microorganisms were identified using biochemical tests. Susceptibility to antibiotics was tested using the Kirby-Bauer method; the inhibition halos were measured according to NCCLS, and based on the results, the microorganisms were classified as susceptible, intermediate or resistant to each antibiotic. Frequencies of species and percentages of resistance were calculated. The microorganisms associated with odontogenic infections were principally anaerobic (65.3% anaerobic vs. 35.7% aerobic), and the susceptibility to antibiotics was higher in anaerobic than in aerobic microorganisms. The majority of isolated microorganisms (82%) showed susceptibility to amoxicillin/clavulanic acid. The causal agents of odontogenic infections were anaerobic microorganisms, which exhibited high resistance to antibiotics.

Sustained release of calcium hydroxide from poly(DL-lactide-co-glycolide) acid microspheres for apexification.

Calcium hydroxide (CH) loaded poly(DL-lactide-co-glycolide) acid (PLGA) microspheres (MS) might be used for apexification requiring a sustained release of Ca(2+). The aim of this study was to formulate and characterize CH-PLGA-MS. The CH-loaded MS were prepared by either oil-in-water (O/W) or water-in-oil/in-water (W/O/W) emulsion solvent evaporation technique. MS produced by the O/W technique exhibited a larger diameter (18.63 ± 7.23 µm) than the MS produced by the W/O/W technique (15.25 ± 7.37 µm) (Mann-Whitney U test P < 0.001). The CH encapsulation efficiency (E e) and Ca(2+) release were calculated from data obtained by absorption techniques. Ca(2+) release profile was evaluated for 30 days. To know the E e, the CH-loaded MS were dissolved in 1 M NaOH to release all its content and a Ca(2+) colorimetric marker was added to this solution. The reagent marked the Ca(2+) in blue color, which was then measured by a UV-Vis system (650 nm). The percentage of E e was calculated on the basis of the theoretical loading. The E e of the O/W-produced MS was higher (24 %) than the corresponding percentage of the W/O/W-produced MS (11 %). O/W- and W/O/W-produced MS released slower and lower Ca(2+) than a control CH paste with polyethylene glycol 400 (Kruskal-Wallis test). O/W-produced MS released higher Ca(2+) than W/O/W-produced MS (statistically significant differences; P < 0.05). In conclusion, the CH-PLGA-MS were successfully formulated; the technique of formulation influenced the size, encapsulation efficiency and release profile. The MS were better sustained release system than the CH paste.

Efficacy of the HBW Ultrasonic Ring for retrieval of fragmented manual or rotatory instruments.

A study was conducted to evaluate the success rates of bypassing or removing fragments of instruments that had fractured within the roots of mandibular molars using a HBW Ultrasonic Ring. Forty extracted first permanent mandibular molars with root canal curvature were included. The teeth were distributed randomly into four groups according to the type of instrument and the root canal third where they had fractured. The success rate for removal of instrument fragments was 100% for both of two stainless steel groups, 90% for a nitinol middle third group, and 80% for a nitinol apical third group. The mean time required for instrument removal was around 40 min. The HBW Ultrasonic Ring showed acceptable experimental results for retrieval of broken instrument fragments.

MTA-Based Cements: Biocompatibility and Effects on the Gene Expression of Collagen Type 1 and TGF-ß1.

Objective: This study sought to evaluate the biocompatibility of Neomineral Trioxide Aggregate (Neo-MTA), MTA Repair High Plasticity (MTA-HP), and Mineral Trioxide Aggregate-Angelus white (MTA-Ang) in fibroblasts of human dental pulp. Materials and Methods: Morphology was evaluated after 24 h of incubation. LIVE/DEAD assay and cell adhesion tests were performed at 24 h of treatment. Cell proliferation assays (MTSs) and Annexin V were performed at 48 h incubation with different treatments. The expression of Col-1 and TGF-ß1 was tested by endpoint PCR at 5 days of treatment. Results: Morphological changes were observed in all groups. Neo-MTA and MTA-Ang were associated with increased cell viability, and all materials induced apoptosis, with a higher percentage in the MTA-HP group than in the other groups. In the LIVE/DEAD assay, there was more damage to the cell membrane in the group of cells treated with MTA-HP than in the other groups. Conclusion: Neo-MTA and MTA-Ang presented similar biocompatibility, and both showed greater biocompatibility than MTA-HP. MTA-HP and MTA-Ang increased Col-1A gene expression, and Neo-MTA and MTA-Ang increased TGF-ß1 gene expression in a similar way.

Comparison between rotary and manual techniques on duration of instrumentation and obturation times in primary teeth.

OBJECTIVE: The aim of this study was to compare the duration of instrumentation and obturation times and quality of root canal filling between rotary and manual instrumentation techniques in primary teeth. STUDY DESIGN: A randomized, controlled clinical trial was performed that included deciduous teeth with pulp necrotic. Forty necrotic teeth were included; 20 were instrumented with a rotary technique (experimental group) and 20 with a manual technique (control group). The time taken for instrumentation and for obturation were recorded in minutes, and the quality of the root canal filling was recorded as optimal, under-filled, or overfilled. RESULTS: The use of the rotary technique diminished the time of instrumentation to 63% and time of obturation to 68%, and it improved the quality of the root canalfilling. CONCLUSION: The use of rotary instruments in the pulpectomy of primary molars represents a promising technique; the time is significantly reduced.

Evaluation of in vitro biofilm elimination of Enterococcus faecalis using a continuous ultrasonic irrigation device.

This study sought to evaluate biofilm elimination using the HBW Ultrasonic Ring based on continuous ultrasonic irrigation. Forty-five premolars and molars with complex curvatures were included. An Enterococcus faecalis biofilm was established for 30 days on the extracted teeth. The teeth were then stratified into three experimental groups for instrumentation and irrigation (i.e. HBW Ultrasonic Ring, conventional irrigation, and passive ultrasonic irrigation). Pre- and post-instrumentation samples were collected, and reductions of bacterial load were evaluated by McFarland's scale, counting of colony-forming units, and scanning electronic microscopy. The HBW Ultrasonic Ring promoted a higher reduction in bacterial load relative to conventional irrigation (P < 0.05) and a similar reduction compared with passive ultrasonic irrigation (P > 0.05). These results suggest the HBW Ultrasonic Ring is a promising alternative modality for simultaneous instrumentation and irrigation during root canal treatment, achieving an appropriate level of bacterial reduction and allowing the passage of the irrigating solution throughout the entire working length.

The effect of Emdogain and 24% EDTA root conditioning on periodontal healing of replanted dog's teeth.

Controversies still exist as for the regenerative role of enamel matrix derivatives and the need for removal of the periodontal ligament in replanted teeth. The purpose of this study was to evaluate the effect of Emdogain and 24% ethylenediamine tetraacetic acid (EDTA) root conditioning on periodontal healing of replanted dog's teeth. Teeth were extracted, endodontically treated and preconditioned as follows: group 1, Emdogain; group 2, Emdogain + EDTA and group 3, EDTA. Teeth were replanted after 30 min extraoral time, splinted for 15 days and animals sacrificed after 8 weeks of observation. Histological evaluation was performed using hematoxylin/eosin and Masson trichrome and results scored based on previously reported criteria for histological evaluation. Replacement root resorption was histologically diagnosed in all groups except in the negative control. A parametric analysis showed no statistically significant differences between experimental groups. Root preconditioning with Emdogain alone or in combination with 24% EDTA showed no evidence of regeneration of collagen fibers and consequently did not prevent the development of replacement root resorption on replanted dog's teeth.

Cytotoxicity, Cell Adhesion, and Apoptotic Gene Expression in Periodontal Ligament Fibroblasts treated with Endodontic Sealers.

OBJECTIVE: The present study assessed cytotoxicity, cell adhesion, and apoptotic gene expression in periodontal ligament fibroblasts (PLF) treated with 2 endodontic sealers. METHODS: PLF cells were obtained from nonerupted third molars and cultured. MTS and LIVE/DEAD assays were performed using different treatments and time periods. Cellular adhesion was evaluated using immunocytochemistry for integrin ß1 and vinculin expression, and the gene expressions of nuclear factor kB (NF-кB), P53, and apoptotic protease-activating factor 1 (Apaf-1) were evaluated using PCR. RESULTS: Cell proliferation at 12, 24, and 48 h was statistically significant in the control and PLF groups receiving different treatments; PLF treated with culture medium containing non-hardened (NH) sealers showed a decrease in the number of cells. PLF treated with culture medium containing hardened (H) sealers also exhibited a decreased cell population. Integrin ß1 and vinculin were expressed in both cell cultures treated with Acroseal (NH and H); however, the cell morphology changed and the cell population decreased. The gene expression of NF-kB and that of P53 were significantly different between the control group and the groups treated with the different sealers; mineral trioxide aggregate (MTA) (NH and H) inhibited Apaf-1, and PLF treated with Acroseal H exhibited increased Apaf-1 expression. CONCLUSION: Both sealers showed a certain level of cytotoxicity. The gene expression of NF-κB and P53 in PLF treated with the sealers showed significant changes compared to that of the control group, and MTA inhibited Apaf-1.

Biocompatibility of bioactive sealers Bio-C sealer vs MTA repair HP in human fibroblasts / Biocompatibilidad de selladores bioactivos Bio-C Sealer vs MTA Repair HP en fibroblastos humanos

Abstract Bioactive cements based on tricalcium silicate have been introducedto the market for use in dentistry, with a variety of clinical applications. These cements are in contact with vital tissues such as dental pulp or periodontium in cases of unintentional extrusion; thus, it is important to know the genotoxicity and cytoxicity of these materials. The objective of this study was to evaluate the cytotoxicity and genotoxicity of bioactive sealers, Bio-C® Sealer and MTA Repair HP®, in human fibroblasts. Discs of bioactive sealers Bio-C® Sealer, and MTA Repair HP®, were prepared and set for 24h under sterile conditions. The discs were placed in culture medium at 2.5mg/mL inside a SRT6D roller mixer (Stuart, UK) at 60rpm for 24h. The eluates obtained were incubated for 24h with previously activated and cultured ATCC cell line fibroblasts at 80% confluence. The cytotoxicity was evaluated by Alamar Blue® and LIVE/ DEAD assays, as well as the analysis of the Tunel and Mitotracker assays to evaluate genotoxicity using the confocal laser-scanning microscope. In the Alamar Blue® assay, the Bio-C® Sealer presented a cell proliferation of 87%, while the MTA Repair HP® Sealer was 72%. A statistically significant difference was found between the MTA Repair HP® Sealant and the negative control (p=<0.001). Regarding the genotoxicity tests, in the Tunel assay, both materials stain the nucleus of the fibroblast cells exposed to the eluates, while in the Mitotracker assay, the MTA Repair HP® Sealer showed greater mitochondrial function than the Bio-C® Sealer. Calcium silicate-based sealers, Bio-C® Sealer and MTA Repair HP®, are not cytotoxic and have low genotoxicity.

Resumen Los cementos bioactivos a base de silicato tricálcico se introdujeron en el mercado para uso en odontología, con una variedad de aplicaciones clínicas. Estos cementos pueden estar en contacto con tejidos como la pulpa dental o el periodonto, en caso de extrusión no intencionada. Por lo tanto, es importante conocer la genotoxicidad y la citoxicidad de estos materiales. El objetivo de este estudio fue evaluar la citotoxicidad y genotoxicidad de los selladores bioactivos Bio-C® Sealer y MTA Repair HP® en fibroblastos humanos. Se prepararon discos de selladores bioactivos Bio-C® Sealer y MTA Repair HP® y se colocaron durante 24h en condiciones de esterilidad. Los discos se colocaron en medio de cultivo a 2,5mg/mL dentro de un mezclador de rodillos SRT6D (Stuart, Reino Unido) a 60rpm durante 24h. Los eluidos obtenidos se incubaron durante 24h con fibroblastos de la línea celular ATCC previamente activados y cultivados al 80% de confluencia. La citotoxicidad se evaluó mediante ensayos Alamar Blue® y LIVE/DEAD; así como el análisis de los ensayos Tunnel y Mitotracker para evaluar la genotoxicidad, utilizando el microscopio confocal láser de barrido. En el ensayo Alamar Blue®, el Sellador Bio-C® presentó una proliferación celular del 87%, mientras que el sellador MTA Repair HP® fue del 72%. Se encontró una diferencia estadísticamente significativa entre el sellador MTA Repair HP® con respecto al control negativo (p=<0.001). En cuanto a las pruebas de genotoxicidad, en el ensayo Tunel, ambos materiales tiñen el núcleo de las células fibroblásticas expuestas a los eluidos, mientras que el ensayo Mitotracker, el sellador MTA Repair HP®, mostró una mayor función mitocondrial que el Bio-C® Sealer. Los selladores a base de silicato de calcio, Bio-C® Sealer y MTA Repair HP® no son citotóxicos y tienen una baja genotoxicidad.

[Frequency of Candida in root canals of teeth with primary and persistent endodontic infections]. / Frecuencia de Candida en conductos radiculares de dientes con infección endodóntica primaria y persistente.

BACKGROUND: Microbiological identification in endodontic infections has focused mainly on bacteria without giving much attention to yeasts, which, due to their virulence factors, can affect the outcomes of root canal treatment. AIMS: To determine the frequency of Candida in anaerobic conditions in root canals with primary and persistent endodontic infection, as well as to evaluate a microbiological sampling method using aspiration compared to the traditional absorption method with paper points. METHODS: Fifty microbiological samples were obtained from teeth of 47 patients requiring endodontic treatments, due to either primary or persistent infections. Two microbiological sampling methods were used: an aspiration method, and the traditional paper point absorption method. In each of these methods, two types of medium were used (M1-M4). Samples were cultured under anaerobic conditions until reaching 0.5 McFarland turbidity, and then inoculated on Sabouraud dextrose, as well as on anaerobic enriched blood agar plates. Macroscopic and microscopic observations of the colonies were performed. The germ-tube test, growth on CHROMagar, and biochemical identification were performed on the isolated yeasts. RESULTS: Fungal infection was found in 18 (36%) samples out of the 50 teeth evaluated. In the 18 samples positive for fungal infection, 15 out of 36 (41.6%) teeth were taken from a primary infection, and 3 out of 14 (21.4%) from a persistent infection. The aspiration method using Sabouraud dextrose medium recovered a greater diversity of species. CONCLUSIONS: Yeasts frequency was higher in teeth with primary infections compared to teeth with persistent infections. The predominant yeast species was Candida albicans. The aspirating sampling method was more efficient in the recovery of Candida isolates than the traditional absorption method.

Chronic Bi-Maxillary Osteomyelitis Caused by Actinomycetes in a Patient with Severe COVID-19 / Osteomyelitis bi-maxilar crónica causada por Actinomycetes en un paciente con COVID-19 severo

Abstract Osteomyelitis is defined as the inflammation of the either medullary, cortical, or cancellous bone, including nerves and blood vessels, causing necrosis and bone sequestrum formation; this condition has become a rare pathology, and odontogenic infections are considered the most frequent causal factor. This case shows a patient with bi-maxillary osteomyelitis caused by Actinomyces spp, which was worsened for severe COVID-19 infection. Patient was submitted at surgery as, amplified total bilateral maxillectomy through the surgical technique Weber-Fergusson, and prolonged use of combination of antibiotics, achieved a good recovery. Two years later follow- up, the patient no show imaging or clinical evidence of the infection of osteomyelitis. The present case shows an interesting relationship between a rare infection and its association with COVID-19.

Resumen La osteomielitis se define como la inflamación del hueso medular, cortical o esponjoso, incluyendo nervios y vasos sanguíneos, causando necrosis y formación de secuestro óseo; esta condición es una patología rara, y las infecciones odontogénicas son consideradas como el factor causal más frecuente. En este caso, se muestra un paciente con osteomielitis bi-maxilar causada por Actinomyces spp, la cual empeoró por la infección de COVID-19 severo. El paciente fue sometido a una cirugía, maxilectomía bilateral total amplificada, a través de la técnica quirúrgica de Weber- Fergusson, y el uso prolongado de una combinación de antibióticos, logrando una buena recuperación. A los 2 años de seguimiento, el paciente no mostró evidencia clínica o imagenológica de la infección de osteomielitis. El presente caso muestra una interesante relación entre una infección rara y su asociación con COVID-19.

Elimination of E. faecalis and C. albicans Biofilm: A comparison between single and multiple file systems in an Ex Vivo study

To evaluate whether the WaveOne Gold and Reciproc single file instrumentation systems, are effective in reducing the microbial load of a mixed biofilm and the cleaning of apical third compared to the Twisted File Adaptive system (multiple- file system). Seventy mesial roots of the first and second molars were included and randomly divided into three experimental groups (n=20, n=10 controls). Biofilms were formed inside canals over 31 days. After instrumentation with the unique file systems, WaveOne Gold and Reciproc and the multiple file system Twisted File Adaptive, using 2.25% sodium hypochlorite as an irrigant in all cases, a count of colony forming units was performed using serial dilutions, cleaning of the apical third was evaluated using scanning electron microscopy. Comparisons amongst groups were made by using parametric and non-parametric statistics, according to a normal or non-normal data distribution, respectively. No significant differences in the reduction of the microbial load after employing a single-file system in comparison to the multiple-file system were found; in addition, the cleaning of the apical third was similar for the three different instrumentation systems. The single-file system is equal in effectiveness compared with the multiple-file system in reducing the microbial load.

Evaluar si los sistemas de instrumentación de lima única, como WaveOne Gold y Reciproc son efectivos para reducir la carga microbiana de un biofilm mixto y la limpieza del tercio apical, comparado con los sistemas de limas múltiples, como Twisted File Adaptive. Setenta raíces mesiales de primeros y segundos molares fueron incluidos y divididos de forma aleatoria en tres grupos experimentales (n=20, n=10 controles). El biofilm fue formado en el interior de los conductos durante 31 días. Después se instrumentó con los sistemas de lima única (WaveOne Gold y Reciproc) y el sistema de limas múltiples Twisted File Adaptive, usando hipoclorito de sodio al 2.5% en todos los casos. El conteo de unidades formadoras de colonias se realizó usando diluciones seriales, la limpieza del tercio apical se evaluó empleando el microscopio electrónico de barrido. La comparación entre grupos se realizó con pruebas paramétricas y no paramétricas, de acuerdo con la distribución normal y no normal de los datos, respectivamente. No hubo una diferencia significativa en la reducción de la carga microbiana después de emplear los sistemas de lima única en comparación a los de limas múltiples, además, la limpieza del tercio apical fue similar en los 3 diferentes sistemas de instrumentación. Los sistemas de lima única son igual de efectivos para reducir la carga microbiana comparados con los sistemas de limas múltiples.

Cytotoxicity and Initial Biocompatibility of Endodontic Biomaterials (MTA and Biodentine™) Used as Root-End Filling Materials.

Objective. The aim of this study was to evaluate the cytotoxicity and cellular adhesion of Mineral Trioxide Aggregate (MTA) and Biodentine (BD) on periodontal ligament fibroblasts (PDL). Methods. PDL cells were obtained from nonerupted third molars and cultured; MTS cellular profusion test was carried out in two groups: MTA and BD, with respective controls at different time periods. Also, the LIVE/DEAD assay was performed at 24 h. For evaluation of cellular adhesion, immunocytochemistry was conducted to discern the expression of Integrin ß1 and Vinculin at 12 h and 24 h. Statistical analysis was performed by the Kruskal-Wallis and Mann-Whitney U tests. Results. MTA and BD exhibited living cells up to 7 days. More expressions of Integrin ß1 and Vinculin were demonstrated in the control group, followed by BD and MTA, which also showed cellular loss and morphological changes. There was a significant difference in the experimental groups cultured for 5 and 7 days compared with the control, but there was no significant statistical difference between both cements. Conclusions. Neither material was cytotoxic during the time evaluated. There was an increase of cell adhesion through the expression of focal contacts observed in the case of BD, followed by MTA, but not significantly.

Elimination of an intraradicular biofilm composed of enterococcus faecalis and candida albicans using a negative apical pressure irrigation system / Eliminación de una biopelícula intraradicular compuesta por enterococcus faecalis y candida albicans utilizando un sistema de irrigación de presión apical negativa

Endodontic treatment consists of the cleaning and disinfecting the root canal system, which is achieved using adequate mechanical instru-mentation and chemical irrigation. Endodontic microorganisms are present in root canals in the form of a biofilm, and their elimination ensures the success of endodontic treatment. Irrigation is a key factor contributing to the elimination of this intraconduct biofilm, and different irrigator agents and irrigation techniques, such as irrigation with negative apical pressure, a novel automated irrigation mechanism based on suction intraconduct, have been used. In this study, we evaluated the ability of a negative apical pressure system with different concentrations of sodium hypochlorite and durations to reduce the microbial load. Materials and Methods: An intraradicular biofilm composed of Enterococcus faecalis and Candida albicans was generated during twenty-one days of static culture on one hundred mesio-vestibular roots of upper molars with complex curvatures greater than 30°C, and the roots were classified in six groups with different concentrations and contact times of sodium hypochlorite. Subsequently, the reduction in the microbial load was measured with McFarland scale and the enumeration of colony forming units and was evaluated with scanning electronic microscopy. Results: We observed a significant difference in the reduction of the microbial load prior to instrumentation compared with postinstrumentation between the groups treated with 2.25% and 5.25% NaOCl for 30, 60 and 90 seconds of contact time (p<0.05), but we did not observe differences in the reduction of microbial load between different contact times and concentrations of sodium hypochlorite employed (p>0.05). Conclusion: Negative apical pressure is a good option for irrigation in endodontics, as it allows the passage of the irrigation fluid along the total length of the root canal and produces a better antimicrobial effect.

El tratamiento de endodoncia consiste en la limpieza y desinfección del sistema de conducto radicular, lo que se logra utilizando instrumentación mecánica adecuada y riego químico. Los microorganismos endodónticos están presentes en los conductos radiculares en forma de una biopelícula, y su eliminación asegura el éxito del tratamiento endodóntico. La irrigación es un factor clave que contribuye a la eliminación de esta biopelícula intraconductora, y se han utilizado diferentes agentes irrigadores y técnicas de irrigación, como la irrigación con presión apical negativa, un nuevo mecanismo automatizado de irrigación basado en la intraconducción de succión. En este estudio, evaluamos la capacidad de un sistema de presión apical negativa con diferentes concentraciones de hipoclorito de sodio y duraciones para reducir la carga microbiana. Material y Métodos: Se generó una biopelícula intraradicular compuesta por Enterococcus faecalisy Candida albicans durante veintiún días de cultivo estático en cien raíces mesio-vestibulares de molares superiores con curvaturas complejas superiores a 30°C, y las raíces se clasificaron en seis grupos con diferentes concentraciones y tiempos de contacto de hipoclorito de sodio. Posteriormente, la reducción en la carga microbiana se midió con la escala de McFarland y la enumeración de las unidades formadoras de colonias y se evaluó con microscopía electrónica de barrido. Resultado: Observamos una diferencia significativa en la reducción de la carga microbiana antes de la instrumentación en comparación con la postinstrumentación entre los grupos tratados con NaOCl 2.25% y 5.25% durante 30, 60 y 90 segundos de tiempo de contacto (p<0.05), pero lo hicimos No se observan diferencias en la reducción de la carga microbiana entre los diferentes tiempos de contacto y las concentraciones de hipoclorito de sodio empleado (p>0.05). Conclusión:La presión apical negativa es una buena opción para el riego en endodoncia, ya que permite el paso del líquido de riego a lo largo de todo el conducto radicular y produce un mejor efecto antimicrobiano.

Evaluation of Apical Transportation by Three Rotary Systems in Extracted Teeth with Curved Canals / Evaluación de la transportación apical con tres sistemas rotatorios en dientes extraídos con conductos curvos

Abstract The aim of this study was to compare the apical transportation in extracted teeth using three different rotary nickel-titanium systems (Mtwo, Hyflex CM, and Typhoon). Sixty extracted first molars were randomly divided into three groups (n=20 in each group) with similar root canal curvatures (25-52 degrees). All root canals were prepared to size 30 using a crown-down preparation technique for each rotary system. Loss of working length and apical transportation were determined by X-ray evaluation. Comparisons between the groups were performed using one-way analysis of variance (ANOVA) or Kruskal-Wallis tests, and the post hoc analyses employed were Dunn´s or Tukey´s multiple comparison tests. No significant differences were detected between the different rotary systems in the loss of working length and apical transportation. This in vitro study showed that the use of these three rotary systems are safe and useful for instrumentation in curved canals; however, further in vivo research is essential to compare the effectiveness and safety of these systems for use in curved canals.

Resumen El objetivo del presente estudio fue comparar la transportación apical en dientes extraídos utilizando tres sistemas rotatorios de níquel-titanio (Mtwo, Hyflex CM y Typhoon). Sesenta primeros molares extraídos se dividieron aleatoriamente en tres grupos (n=20 en cada grupo) con curvaturas del conducto radicular similares (25-52 grados). Todos los conductos radiculares se prepararon usando una técnica corono apical para cada sistema rotatorio. La pérdida de la longitud de trabajo y la transportación apical se determinaron mediante evaluación radiográfica. Las comparaciones entre los grupos se realizaron utilizando análisis de varianza de una vía (ANOVA) o Kruskal-Wallis, y los análisis post hoc empleados fueron las pruebas de comparación múltiple de Dunn o Tukey. No se detectaron diferencias significativas entre los diferentes sistemas rotatorios en la pérdida de la longitud de trabajo y transportación apical. Este estudio demostró que el uso de estos tres sistemas es seguro y útil para su instrumentación en conductos curvos; sin embargo, investigación in vivo es necesaria para comparar la efectividad y seguridad de estos sistemas para su uso en conductos curvos.

Automatic Electronic Device Used for the Evaluation of Cyclic-Fatigue Resistance of Nickel-Titanium Instruments

he aim of this study was to evaluate the cyclic-fatigue fracture of different Nickel-Titanium motor-driven rotary instruments (ProTaper® Universal, ProFile®, and Mtwo® systems) in artificial canals by means of an Automatic Electronic Device (AED). The study was performed using NickelTitanium instruments 25/0.06 evaluated in canals with a 45-degree curvature and 2-mm radius. The analyses evaluated two parameters: fracture by cyclic fatigue, and time of fracture; in addition, the length of separated fragment was evaluated. Medians and range values were calculated for each group. Data were analyzed by the Kruskall-Wallis and Mann-Whitney U tests to determine statistical difference. The ProFile motor-driven rotator system exhibited highest resistance to fracture due to cyclic fatigue and highest fracture time compared with the ProTaper and Mtwo systems (p <0.05). The equipment proposed in this study (AED) demonstrated efficiency for recording information, automation, scheduled work times and durations, cycle number, time of fracture, pressure changes and, principally control of the human factor.

l objetivo del presente estudio fue evaluar la fractura a la fatiga cíclica de diferentes instrumentos rotatorios de Niquel-Titanio (sistemas ProTaper® Universal, ProFile® y Mtwo®) en conductos artificiales por medio de un Dispositivo Electrónico Automático (DEA). Se usaron instrumentos de Niquel-Titanio 25/0.06, los cuales se evaluaron en conductos con una curvatura de 45 grados y 2 milímetros de radio. Se analizaron dos parámetros: Fractura a la fatiga cíclica y tiempo a la fractura; además se evaluó la longitud del fragmento separado. Medianas y rangos fueron calculados para cada uno de los grupos. Los resultados fueron analizados por las pruebas de Kruskall-Wallis y U de Mann-Whitney para determinar diferencias estadísticas. El Sistema ProFile mostró una mayor resistencia y tiempo a la fractura en comparación con los sistemas ProTaper y Mtwo (p <0.05). El equipo propuesto en este estudio (DEA) demostró eficiencia para el registro de la información, tiempos de trabajo y duración, número de ciclos, tiempo a la fractura, cambios en la presión y principalmente control del factor humano.

Clinical efficacy of low level laser therapy in reducing pain and swelling after periapical surgery: a preliminary report / Eficacia clínica de láser terapéutico de bajo nivel de emisión en la reducción de dolor e inflamación posterior a cirugía periapical: reporte preliminar

The objective of this study was to evaluate the efficacy of the low level laser therapy (LLLT) in postoperative pain and swelling associated with periapical surgery. A double-blind, randomized, controlled clinical trial was carried out in 2 groups of 10 patients each, undergoing periapical surgery. The experimental group was treated with an intraoral application of an 810 nm-GaAsAl-laser, having an output power of 100 mW, with overlapping movements over the wound. In the control group, the same procedure was carried out, without therapeutic laser activation. Postoperative pain, swelling, and rescue medication were registered. The experimental group exhibited a decrease in pain intensity after periapical surgery compared with control group (p<0.05). There was not significant statistical difference between the groups in terms of swelling. Six patients of the control group required rescue medication. The use of LLLT in the postoperative management of patients having periapical surgery, using the protocol of this study reduced postoperative pain...

El objetivo del estudio fue evaluar la eficacia del láser terapéutico de bajo nivel de emisión (LTBNE) en el dolor postoperatorio e inflamación asociados con cirugía periapical. Se realizó un ensayo clínico controlado aleatorizado doble ciego en 2 grupos de 10 pacientes cada uno, que requirieron de cirugía periapical. El grupo experimentalfue tratado con una aplicación intraoral de laser de GaAsAl de 810 nm, con una potencia de 100 Mw, con movimientos oscilatorios sobre la herida quirúrgica. En el grupo control, se llevó a cabo el mismo procedimiento, sin la activación del láser terapéutico. Se registraron dolor postoperatorio, inflamación y medicación de rescate. El grupo experimental mostró una disminución en la intensidad del dolor posterior a la cirugía periapical en comparacióncon el grupo control (p<0.05). No se encontró diferencia estadísticamente significativa entre los grupos entérminos de inflamación. Seis pacientes del grupo control requirieron medicación de rescate. El uso de LTBNE en el manejo postoperatorio de pacientes sometidos a cirugíaperiapical, usando el protocolo del presente estudio redujo el dolor postoperatorio...