Probiotics enhance alveolar bone microarchitecture, intestinal morphology and estradiol levels in osteoporotic animals.

BACKGROUND AND OBJECTIVE: Osteoporosis is associated with bone microarchitecture alterations, and the depletion of estrogen during menopause is a major contributing factor to its development. The literature highlights the noteworthy role of gut microbiota in bone metabolism, particularly in the progression of osteoporosis. Periodontal disease leads to alveolar bone loss, which may be influenced by estrogen deficiency, and this mechanism is intricately associated with an imbalance in systemic microbiota. The aim of this study was to evaluate the effects of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) and Lacticaseibacillus casei 01 (L. casei 01) administrations on an osteoporosis animal model. MATERIALS AND METHODS: Thirty-three female rats were randomly divided into three groups: control (C-OVX), C-OVX-HN019 and C-OVX-LC01. All animals were ovariectomized. In groups C-OVX-HN019 and C-OVX-LC01, the probiotics were administered for 4 months. All animals were euthanized after 16 weeks from ovariectomy. Microtomographic, histopathological and immunohistochemical examinations were conducted on periodontal tissues, whereas histomorphometry, histopathological and immunohistochemical analyses were carried out on the intestine. The levels of estradiol were assessed in blood using an immunoenzymatic assay. The data were subjected to statistical analyses (p < .05). RESULTS: The C-OVX-LC01 group exhibited a significant reduction in alveolar bone porosity and an increase in connective tissue density compared to C-OVX (p < .05). The C-OVX-HN019 and C-OVX-LC01 groups presented reduced expression of TRAP and RANKL compared to the C-OVX (p < .05). The C-OVX group presented villi defects, mild neutrophil infiltration, decrease in both villous height and intestinal crypts and reduced expression of intestinal junctional epithelium markers e-cadherin and claudin 01 compared to C-OVX-HN019 and C-OVX-LC01 (p < .05). The C-OVX group had lower estradiol levels than C-OVX-HN019 and C-OVX-LC01 (p < .05). CONCLUSION: The probiotic therapy promoted a reduction in alveolar bone destruction and intestinal permeability as well as an increase in estradiol levels in ovariectomized rats. Specifically, the probiotic strain Lacticaseibacillus casei 01 exhibited greater effectiveness compared to Bifidobacterium animalis subsp. lactis HN019, indicating strain-dependent outcomes.

Spectrophotometric Analysis of Apical Extrusion of Sodium Hypochlorite using Different Irrigation Protocols in an Ex Vivo Model of Immature Teeth.

OBJECTIVE: To evaluate the effect of different agitation methods on apical extrusion of 1.5% sodium hypochlorite (NaOCl) in an ex vivo model of immature teeth. METHODS: Sixty extracted human inferior incisors were prepared to simulate immature teeth and embedded in an artificial root socket made of silicone impression material. The teeth were then divided into four groups: Conventional needle irrigation (CNI) alone, CNI supplemented with Ultrasonic Irrigant Activation (UIA), EasyClean (EC), or XP-endo Finisher (XPF). Extruded NaOCl was collected, reacted with m-cresol purple, and its absorbance values were measured. The data were statistically analyzed using One-way analysis of variance with a significance level of 5%. RESULTS: All groups showed apically extruded irrigating solution, and the mean volumes of extruded NaOCl did not differ significantly between any of the test groups (p⟩0.05). CONCLUSION: The activation of 1.5% NaOCL by UIA, EC, or XPF as supplementary to CNI does not promote greater apical extrusion when compared to CNI alone in simulated immature teeth.

Bismuth release from endodontic materials: in vivo analysis using Wistar rats.

Calcium silicate-based materials are used to block the communication between the root canal and the periodontal ligament space. This brings the materials into contact with tissues and the potential for local and systemic elemental release and movement. The aim of the study was to evaluate the elemental release of bismuth from ProRoot MTA in contact with connective tissues after 30 and 180 days as well as any accumulation in peripheral organs using an animal model. Tricalcium silicate and hydroxyapatite containing 20% bismuth oxide (HAp-Bi) were used as controls. The null hypothesis was that bismuth migrates from tricalcium silicate-based materials when associated with silicon. The materials were examined using scanning electron microscopy, energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction prior to implantation as well as using SEM/EDS, micro X-ray fluorescence and Raman spectroscopy after implantation to assess elemental presence in surrounding tissues. Histological analysis was used to evaluate the changes in tissue architecture and inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the elemental deposition. For the systemic investigation, routine blood analysis was performed and organs were obtained to evaluate the presence of bismuth and silicon using ICP-MS after acid digestion. In the histological analysis of the implantation sites, macrophages and multinucleated giant cells could be observed after 30 days which after 180 days became a chronic infiltrate; although, no major differences were identified in red and white blood cell analyses and biochemical tests. Implantation altered the materials as observed in the Raman analysis and bismuth was detected both locally and within kidney samples after both periods of analysis, indicating the potential for accumulation of bismuth in this organ. Smaller amounts of bismuth than observed in the kidney were also detected in blood, liver and brain for the ProRoot MTA and HAp-Bi after 180 days. Bismuth was released from the ProRoot MTA locally and was detected systemically and in samples without silicon; thus, the null hypothesis was rejected. The bismuth release demonstrated that this element accumulated both locally and systemically, mainly in the kidneys in comparison with brain and liver regardless of the material base.

Quantitative analysis of culturable bacteria, levels of endotoxins, inflammatory mediators and substance P in teeth with symptomatic irreversible pulpitis and in teeth with vital normal pulp tissues.

AIM: To comparatively analyse the levels of culturable bacteria, endotoxins (LPS), tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß) and substance P in teeth with symptomatic irreversible pulpitis (SIP) and vital normal pulp (VNP) tissues. METHODOLOGY: Thirty-two patients were included (20 teeth with SIP and 12 teeth with VNP tissues) in this cross-sectional study. Samples were collected from the full length of the root canals (microbial analysis) and periapical tissues (2 mm beyond the apex for immunological analysis), using sterile absorbent paper points. The levels of culturable bacteria (culture method), endotoxins (LAL Pyrogent 5000), TNF-α, IL-1ß and substance P (ELISA) were assessed. The Mann-Whitney test was used for comparisons between the levels of CFU/mL, LPS, TNF-α, IL-1ß and substance P in the SIP and VNP groups. The statistical analysis was performed with the significance level set at 5%. RESULTS: Culturable bacteria were recovered from all teeth with SIP. On the other hand, no positive cultures were observed in the VNP tissues group (p > .05). The levels of LPS were approximately four times higher in teeth with SIP than in teeth with VNP tissues (p < .05). Higher levels of TNF-α and substance P were detected in teeth with SIP (p < .05). On the other hand, no difference in the levels of IL-1ß was detected between the two groups (p > .05). CONCLUSION: Teeth with symptomatic irreversible pulpitis present higher levels of culturable bacteria, endotoxins, TNF-α and substance P than those with vital normal pulp tissues. On the other hand, the levels of IL-1ß were similar in teeth from both groups suggesting reduced implications of this inflammatory mediator in the early stages of infection.

Tomografía computarizada en la identificación de la sinusitis odontogénica de origen endodóntico: reporte de un caso / Computerized tomography in the identification of odontogenic sinusitis of endodontic origin: report of a case

Objetivo: se presenta el caso clínico de sinusitis de origen endodóntico, conocida como síndrome en-doantral, haciendo énfasis en la dificultad de diag-nóstico con radiografía periapical y la importancia de la tomografía computarizada. Caso clínico: una mujer de 32 años, con antecedentes de apretamiento dental nocturno y sinusitis recurrente, fue remitida para evaluación endodóntica. El examen clínico reve-ló sensibilidad a la percusión y palpación en la unidad dental. La radiografía periapical no indicó lesión en el diente 16 y la prueba de sensibilidad pulpar fue ne-gativa, además, la tomografía computarizada reveló una extensa lesión periapical y comunicación entre la raíz del diente 16 y el seno maxilar, confirmada por la pérdida de la continuidad de la imagen hiperdensa en el suelo del seno, lo que llevó al tratamiento endo-dóntico. El control de la infección dental resolvió la sinusitis, resaltando la importancia del diagnóstico preciso y el tratamiento en casos de sinusitis odon-togénica. Conclusión: este caso destaca el valor de la tomografía computarizada como herramienta diag-nóstica crucial en contextos clínicos complejos (AU)

Objective: the clinical case of sinusitis of endodontic origin, known as endoantral syndrome, is presented, emphasizing the difficulty of diagnosis with periapical radiography and the importance of computed tomography. Clinical case: a 32-year-old woman, with a history of tooth clenching and recurrent sinusitis, was referred for endodontic evaluation. The clinical examination revealed sensitivity to percussion and palpation in the dental unit. The periapical radiograph did not indicate a lesion in tooth 16 and the pulp sensitivity test was negative, in addition, the computed tomography revealed an extensive periapical lesion and communication between the root of tooth 16 and the maxillary sinus, confirmed by the loss of continuity of the hyperdense image in the sine floor, which led to endodontic treatment. Dental infection control resolved sinusitis, highlighting the importance of accurate diagnosis and treatment in cases of odontogenic sinusitis. Conclusion: this case highlights the value of computerized tomography as a crucial diagnostic tool in complex clinical contexts (AU)

Electrochemotherapy as palliative treatment in patients with recurrent and/or metastatic head and neck tumours: features analysis for an early determination of the partial responsive patients.

OBJECTIVE: The aim of this study was to identify features mainly involved in determining the partial response (PR) to the Electrochemotherapy (ECT) in patients with recurrent and/or metastatic head and neck (H&N) tumor; the identified features were also used in a decision chart in order to provide the clinician with a support tool in deciding further therapies. PATIENTS AND METHODS: 131 patients (186 treatment sessions) with recurrent and/or metastatic H&N neoplasm were subjected to ECT. Treatment response was evaluated based on Response Evaluation Criteria in Solid Tumors (RECIST) v. 1.1 two months after the ECT. The grade of bleeding and pain before, at the end and one week after ECT treatment were evaluated. Univariate and multivariate analysis were performed to identify features involved in determining the patient PR. RESULTS: In the context of the univariate analysis, tumor size significantly influenced the response to ECT, with higher PR rate of 58.3%: 28 among 48 patients with lesion size ≤ 3 centimeters (p-value < 0.001 at Chi-square test). Pain and bleeding pre-treatment were positively correlated to PR (p-value < 0.001 at Chi-square test). A difference in the current flowing in the tissue during treatment was also observed in partially responsive patients, where the median current value (6.6 A) was higher than that achieved in patients that did not show PR (3.3 A). In the context of the multivariate analysis, the best performances are achieved with the BART method (accuracy of 84%). The main clinical factors to predict the partial response, among investigated features, that have shown to be considered were the pain value felt before performing the treatment and the median current delivered during the ECT treatment. A decision-making support tool to predict the patient prognosis in terms of response rate could be represented by the decision tree obtained with CART algorithm, where a pain pre-treatment more than 5 and a median delivered current not less than 2.8 A led to the prediction a partial responsive patient with an accuracy of 75%. CONCLUSIONS: The study confirmed that ECT is an interesting antitumoral therapy in advanced chemo- and radio-refractory H&N neoplasms, able to reduce frequent symptoms and to improve the quality of life. Pain pre-treatment and delivered current are the most important variables when predicting the partial response of patients.

Heating stability, physical and chemical analysis of calcium silicate-based endodontic sealers.

AIM: To evaluate possible modifications in root canal sealers subjected to a variety of heating conditions using vibrational spectroscopy and analysis of physical and chemical properties. METHODOLOGY: EndoSequence BC Sealer HiFlow, Bio-C Sealer, BioRoot RCS and AH Plus were analysed chemically using Raman spectroscopy (25-220 °C) and Fourier-transform infrared spectroscopy (FT-IR) (37-100 °C ). For FT-IR, the materials were tested individually and mixed with root dentine powder. Scanning electron microscopy (SEM) and coupled energy dispersive spectroscopy (EDS) were used to evaluate surface and chemical elements. ISO 6876-2012 and ASTM-C266-07 specifications were followed to evaluate flow, setting time (moist and dry), solubility and radiopacity. Also, pH analysis at 37 and 100 °C was performed. Shapiro-Wilk and Mixed ANOVA (within and between the effects of the subjects), Levene, and a post hoc analyses with Bonferroni correction were performed (P < 0.05). RESULTS: Vibrational spectroscopy revealed peaks of tricalcium silicate, dicalcium silicate and zirconium dioxide. Chemical changes in the Raman spectra during heating were discrete, as the inorganic content predominated the signalling for all root canal sealers. FT-IR analysis exhibited spectral changes in water absorption for EndoSequence BC Sealer HiFlow and Bio-C Sealer, probably related to dehydration. For BioRoot RCS and AH Plus, no significant chemical changes were observed. Bio-C Sealer exhibited a band of polyethylene glycol only after heating to 100 °C, probably related to its thermal decomposition. SEM/EDS analysis corroborated the composition results observed in vibrational spectroscopy for all materials. Heating to 100 °C significantly changed the flowability of all calcium silicate-based sealers with a wide variation in setting times at both temperatures, along with solubility levels above ISO standards. For all tested sealers, radiopacity fulfilled the requirements, and pH exhibited alkaline values. CONCLUSIONS: The tested calcium silicate-based sealers were affected by heating. Calcium silicate-based root canal sealers had high solubility which is a concern for their clinical use. AH Plus was the only root canal sealer that was stable after heating.

Bacteria and virulence factors in periapical lesions associated with teeth following primary and secondary root canal treatment.

AIM: This cross-sectional study aimed to investigate the microbial profile and to quantify the levels of endotoxins (LPS) and lipoteichoic acid (LTA) present in periapical lesions associated with root filled teeth and those that had received root canal retreatment. It also aimed to investigate the association between microorganisms and their virulence factors with clinical and radiographic features. METHODOLOGY: Patients with periapical lesions in teeth with post-treatment endodontic disease following primary root canal treatment (n = 19) and unsuccessful root canal retreatment (n = 13) were treatment planned for endodontic microsurgery, where the periapical lesions were collected. Clinical and radiographic data were also collected. For microbiological analysis, nested polymerase chain reaction was used to detect 17 bacterial species. Levels of LPS and LTA were determined using limulus amebocyte lysate and enzyme-linked immunosorbent assays, respectively. The Student t-test or Wilcoxon-Mann-Whitney tests were applied to compare the data on LPS and LTA with clinical and radiographic features. The associations between the clinical and radiographic features and the bacterial species were analysed using the Fisher's exact test. A significance level of 5% was adopted. RESULTS: Bacterial DNA, LPS and LTA were detected in all samples. Parvimonas micra was the most commonly detected species in all groups, followed by Enterococcus faecalis, Fusobacterium nucleatum and Porphyromonas endodontalis. The type of endodontic treatment, whether a primary root canal treatment or retreatment, was not associated with the presence of any bacterial species in periapical lesions. The levels of LPS and LTA in periapical lesions of root filled teeth were not significantly different from those that had been retreated. Associations between the levels of LPS and LTA with clinical signs and symptoms were found. No association was found between specific bacteria and clinical features. CONCLUSION: Periapical lesions associated with teeth after primary root canal treatment and retreatment had similar polymicrobial composition. The levels of LPS and LTA in periapical lesions associated with teeth after primary root canal treatment and retreatment were similar, and both were associated with the same symptomatology.

Efficacy of reciprocating and ultrasonic activation of 6% sodium hypochlorite in the reduction of microbial content and virulence factors in teeth with primary endodontic infection.

AIM: To evaluate in a clinical trial the efficacy of reciprocating and ultrasonic activation of 6% sodium hypochlorite (NaOCl) in the microbial composition and reduction in microbial load as well as in levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) in teeth with primary endodontic infections. METHODOLOGY: Samples were collected from 24 root canals with pulp necrosis and periapical lesions, before and after chemo-mechanical canal preparation. The teeth were randomly divided according to the activation protocol as follows: control group without activation (WA, n = 8), reciprocating activation group using Easy Clean tip (EC, n = 8) and ultrasonic activation group using Irrisonic insert (US, n = 8). Microbiological specimens were processed using a culture technique and microbiota composition was analysed using the checkerboard technique. The levels of LPS and LTA were quantified using limulus amebocyte lysate (LAL) and enzyme-linked immunosorbent assay (ELISA), respectively. The Fisher's exact test, Kruskal-Wallis, Dunn's and Wilcoxon's test with a significance level of P < 0.05 were used for statistical analysis. RESULTS: All initial specimens had growth of viable bacteria in fastidious anaerobe agar (FAA), with an average of 105  CFU mL-1 , whereas only one case had such growth after chemo-mechanical canal preparation. LPS and LTA were recovered in 100% of the cases. Chemo-mechanical canal preparation significantly decreased the levels of LPS and LTA (P < 0.05), but no significant differences were found between the groups (P > 0.05). Through the checkerboard technique, bacteria were found in 100% of the initial specimens with concentrations between <105 and 106 . The most frequently identified microorganisms were Prevotella nigrescens and Enterococcus hirae. After chemo-mechanical canal preparation, many species were not detected in any of the three groups tested. A significant reduction occurred in Group US, followed by Groups EC and WA. CONCLUSIONS: Activation of 6% NaOCl reduced the levels of LPS and LTA with no differences between the groups. However, ultrasonic activation was associated with a greater reduction in microbial load within root canals.

Nontargeted Analytical Methods as a Powerful Tool for the Authentication of Spices and Herbs: A Review.

Food fraud in herbs and spices is an important topic, which has led to new technologies being studied as potential tools for fraud identification. Nontargeted technologies have proven to be a useful tool for the authentication of herbs and spices. The present review focuses on the use of near-infrared, hyperspectral imaging, Fourier-transform infrared, Raman, nuclear magnetic resonance, and electron spin resonance spectroscopy for the authentication of spices, which includes the determination of origin and irradiated spices and the identification of adulterants. The methods developed based on vibrational spectroscopy combined with chemometric techniques seem to be promising tools for determining the presence of adulterants and contaminants in herbs and spices. On the other hand, nuclear magnetic resonance seems to be the most efficient technology to determine the origin of herbs and spices although, for some cases, studies with near-infrared spectroscopy can be a viable substitute. Electron spin resonance spectroscopy is the technique par excellence used for the authentication of irradiated herbs and spices, so its use should be expanded to many more spices' varieties. Portable devices are preferred by those involved in the food industry, due to its manageability and low cost. Data fusion and big data are shown as promising tools for spice fraud control. In conclusion, spectroscopic techniques show a great efficiency to authenticate spices, although their evaluation must be expanded to other spice varieties, to new strategies of data analysis (as data fusion and big data), and to the use of portable devices.

Relación entre el piso del seno maxilar y las raíces de las piezas posteriores superiores, mediante tomografía computada / Relationship between maxillary sinus floor and the posterior upper teeth roots, by means of computed tomography

Objetivo: El objetivo de este estudio fue evaluar la frecuencia con que las raíces de premolares y molares superiores se encuentran dentro del seno maxilar. Conocer la relación entre dichas estructuras es importante para planificar los procedimientos endodónticos y quirúrgicos a ser realizados en esa región. Materiales y métodos: Se realizó el análisis cualitativo dinámico de 82 tomografías computadas de haz cónico (CBCT) unilaterales, analizándose 738 raíces correspondientes a premolares y molares de una sola hemiarcada superior. Se utilizó sala con iluminación controlada y la observación fue realizada por un solo examinador. El criterio de inclusión requería que la cortical inferior del seno maxilar debía ser visible para poder establecer la relación. Se utilizaron los tres planos tomográficos de visualización, permitiendo ajustes de brillo y contraste. La escala de clasificación de cada raíz consideró su relación como: dentro o fuera del seno maxilar. Los datos obtenidos fueron sometidos a las pruebas de Chi-cuadrado y Test Exacto de Fisher. Resultados: el primer premolar superior mostró una proyección hacia el interior del seno maxilar significativamente menor que las otras piezas dentarias posteriores (p>0.05), observándose su raíz vestibular sin proyección. La raíz palatina del primer premolar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% del total de las raíces analizadas (p<0,05). El segundo molar superior mostró considerable proximidad con el seno maxilar, pero con menor incidencia con relación a la raíz palatina del primer molar. Conclusión: los procedimientos endodónticos o quirúrgicos a realizarse en cercanía al seno maxilar deben considerar siempre la relación raíz/seno, para evitar maniobras que lo invadan. La raíz palatina del primer molar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% (AU)

The effect of mixing method on tricalcium silicate-based cement.

AIM: To evaluate the effect of three methods of mixing on the physical and chemical properties of tricalcium silicate-based cements. METHODOLOGY: The materials evaluated were MTA Angelus and Portland cement with 20% zirconium oxide (PC-20-Zr). The cements were mixed using a 3 : 1 powder-to-liquid ratio. The mixing methods were manual (m), trituration (tr) and ultrasonic (us) activation. The materials were characterized by means of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy. Flowability was analysed according to ANSI/ADA 57/2012. Initial and final setting times were assessed following ASTM C266/08. Volume change was evaluated using a micro-CT volumetric method. Solubility was analysed according to ADA 57/2012. pH and calcium ion release were measured after 3, 24, 72 and 168 h. Statistical analysis was performed using two-way analysis of variance. The level of significance was set at P = 0.05. RESULTS: The SEM analysis revealed that ultrasonic activation was associated with a homogeneous distribution of particles. Flowability, volume change and initial setting time were not influenced by the mixing method (P > 0.05). Solubility was influenced by the mixing method (P < 0.05). For pH, at 168 h, significant differences were found between MTA-m and PC-20-Zr-m (P < 0.05). For calcium ion release, PC-20-Zr-tr had higher values than MTA-m at 3 h, and MTA-tr had higher values than PC-20-Zr-m at 168 h (P < 0.05). CONCLUSIONS: The ultrasonic and trituration methods led to higher calcium ion release and pH compared with manual mixing for all cements, whilst the ultrasonic method produced smaller particles for the PC-20-Zr cement. Flow, setting times and volume change were not influenced by the mixing method used; however, it did have an impact on solubility.

Efficacy of xylene and passive ultrasonic irrigation on remaining root filling material during retreatment of anatomically complex teeth.

AIM: To evaluate the volume of remaining filling material in the mesial root canals of mandibular molars after root canal retreatment with different procedures performed sequentially. METHODOLOGY: The mesial root canals of 12 human first mandibular molars were instrumented using the BioRace system until a size 25, .06 taper instrument. The mesial roots were filled with gutta-percha and AH-Plus using a vertical compaction technique. The specimens were scanned using microcomputed tomography with a voxel size of 16.8 µm before and after the retreatment procedures. To remove the filling material, the root canals were enlarged until the size 40, .04 taper instrument. The second step was to irrigate the root canals with xylene in the attempt to clean the root canals with paper points. In the third step, the passive ultrasonic irrigation technique (PUI) was performed using 2.5% sodium hypochlorite. The initial and residual filling material volume (mm(3) ) after each step was evaluated from the 0.5 to 6.5 mm level. The obtained data were expressed in terms of percentage of residual filling material. Statistical analysis was performed using the Friedman test (P < 0.05). RESULTS: All specimens had residual filling materials after all retreatment procedures. Passive ultrasonic irrigation enhanced the elimination of residual filling material in comparison with the mechanical stage at the 0.5-2.5 mm and 4.5-6.5 mm levels (P < 0.05). No significant difference was found between xylene and PUI methods. CONCLUSIONS: Filling materials were not completely removed by any of the retreatment procedures. The use of xylene and PUI after mechanical instrumentation enhanced removal of materials during endodontic retreatment of anatomically complex teeth.

Influence of powder-to-water ratio on radiopacity, setting time, pH, calcium ion release and a micro-CT volumetric solubility of white mineral trioxide aggregate.

AIM: To evaluate the radiopacity, setting time, pH level, calcium ion release and solubility of white mineral trioxide aggregate (MTA; Angelus, Londrina, Pr, Brazil) with different powder-to-water ratios. METHODOLOGY: Three MTA groups were prepared using 4 : 1, 3 : 1 and 2 : 1 powder-to-water ratios. For the radiopacity analysis, the 10 × 1 mm specimens were arranged on occlusal films with a cylinder of dentine and an aluminium stepwedge. The digitized radiographs were evaluated with Digora 1.51 software to determine the radiographic density. The setting time test was performed according to the American Society for Testing and Materials 266/08 standard specifications, but the specimens were made according to International Organization for Standardization 6876:2001. Thirty acrylic teeth with root-end filling material were immersed in ultrapure water for measurement of pH level and calcium ion release (atomic absorption spectrophotometer) at 3, 24, 72 and 168 h. In the solubility test, the root-end fillings of 30 acrylic teeth were scanned twice by a Micro-CT, before and after immersion in ultrapure water for 168 h. Digital data were reconstructed, and the volume (mm(3) ) of the samples was obtained using CTan software (CTan v1.11.10.0, SkyScan). The data were statistically analysed by the anova, Tukey, Kruskal-Wallis and Dunn's tests. RESULTS: The radiopacity was higher (P < 0.05) when the 4 : 1 proportion was utilized. The setting time was longer, and the pH level and calcium ion release were higher (P < 0.05) with a greater volume of water. The group with more water (2 : 1) had significantly (P < 0.05) more material volume loss (6.46%) compared with the other groups. CONCLUSIONS: The ratio of powder/water significantly interfered with the physical and chemical properties of white MTA Angelus.

Antimicrobial effect of endodontic solutions used as final irrigants on a dentine biofilm model.

AIM: To evaluate the residual biovolume of live bacterial cells, the mean biofilm thickness and the substratum coverage found in mixed biofilms treated with different endodontic irrigant solutions. METHODOLOGY: Twenty-five bovine dentine specimens were infected intraorally using a removable orthodontic device. Five samples were used for each irrigant solution: 2% chlorhexidine, 1% sodium hypochlorite (NaOCl), 10% citric acid, 17% EDTA and distilled water. The solutions were used for 5 min. The samples were stained using the Live/Dead technique and evaluated using a confocal microscope. Differences in the amount of total biovolume (µm(3)), number of surviving cells (µm(3)), mean biofilm thickness (µm) and substratum coverage (%) of the treated biofilms were determined using nonparametric statistical tests (P < 0.05). RESULTS: Similar values of biovolume total, biovolume of live subpopulations and substratum coverage were found in 2% chlorhexidine, 10% citric acid, 17% EDTA and distilled water-treated biofilms (P > 0.05). The lower values of the studied parameters were found in 1% NaOCl-treated dentine (P < 0.05) with the exception of the mean biofilm height criteria that did not reveal significant differences amongst the irrigant solutions (P > 0.05). CONCLUSIONS: One per cent sodium hypochlorite was the only irrigant that had a significant effect on biofilm viability and architecture.

Analysis of four gutta-percha techniques used to fill mesial root canals of mandibular molars.

AIM: To compare the percentage of gutta-percha, sealer and voids and the influence of isthmuses in mesial root canals of mandibular molars filled with different techniques. METHODOLOGY: Canals in 60 mesial roots of mandibular first molars were prepared with ProTaper instruments to size F2 (size 25, 0.08 taper) and filled using a single-cone, lateral compaction, System B or Thermafil techniques. An epoxy resin sealer was labelled with Rhodamine-B dye to allow analysis under a confocal microscope. The percentage of gutta-percha, sealer and area of voids was calculated at 2, 4 and 6 mm from the apex, using Image Tool 3.0 software. Statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn tests (P < 0.05). The influence of isthmuses on the presence or absence of voids was evaluated using the Fisher test. RESULTS: At the 2 mm level, the percentage of gutta-percha, sealer and voids was similar amongst the System B, lateral compaction and single-cone techniques. The single-cone technique revealed significantly less gutta-percha, more sealer and voids in comparison with the Thermafil technique at the 2 and 4 mm level (P < 0.05). The analysis of all sections (2, 4 and 6 mm) revealed that more gutta-percha and less sealer and voids were found in root canals filled with Thermafil and System B techniques (P < 0.05). The Fisher test revealed that the presence of isthmuses increased the occurrence of voids in the lateral compaction group only (P < 0.05). CONCLUSION: Gutta-percha, sealer filled area and voids were dependent on the canal-filling technique. The presence of isthmuses may influence the quality of root filling.

Neuroprotective effects of Ginkgo biloba extract in brain ischemia are mediated by inhibition of nitric oxide synthesis.

We studied the effects of pre-treatment (15 days) with oral administration of Ginkgo biloba extract (Ph-Gb 37.5-150 mg/kg) on brain malonildialdehyde (MDA), brain edema, brain nitrite and nitrate and delayed neuronal death following transient cerebral ischemia in the Mongolian gerbil. Survival was not modified, however, pre-treatment with Ginkgo biloba significantly and in a dose-dependent way reduced post-ischemic brain MDA levels and post-ischemic brain edema. Delayed neuronal death in the CA1 of the hippocampus was attenuated by the highest dose of the extract. Increase of nitrite and nitrate was observed after cerebral ischemia in the hippocampus and it was dose-dependently reduced in animals pretreated with Ph-Gb, thus suggesting that neuroprotective effects of Ginkgo biloba may be due to an inhibitory action on nitric oxide formation.

Erythropoietin protects against brain ischemic injury by inhibition of nitric oxide formation.

Erythropoietin prevents in vitro glutamate-induced neuronal death and could play a role in the central nervous system. We investigated the in vivo effects of recombinant human erythropoietin after intraperitoneal (i.p.; 25-100 U) or intracerebroventricular (i.c.v.; 0.25-25 U) administration on survival, brain malonildialdehyde (MDA) levels, brain edema, hippocampal neuronal death and brain nitric oxide (NO) synthesis after bilateral carotid occlusion (5 min), followed by reperfusion in the Mongolian gerbil. Peripheral posttreatment with recombinant human erythropoietin reduced postischemic MDA levels, brain edema and increased survival. Either peripheral or i.c.v. posttreatment with recombinant human erythropoietin significantly reduced hippocampal CA1 neuronal loss, observed 7 days after the ischemic event. Increase of nitrite and nitrate (as an index of NO formation) in the hippocampus, as observed after ischemia, was reduced in animals treated with recombinant human erythropoietin. These data suggest that in vivo recombinant human erythropoietin effects on brain ischemic injury could be due to inhibition of NO overproduction.