Influence of ultrasonic agitation on pH and antibiofilm activity of endodontic sealers: an in vitro study

Background: The influence of ultrasonic agitation (UA) on the pH and antibiofilm activity of AH Plus Jet (AHP) and BioRoot RCS (BCS) sealers was evaluated. Subgroups were created based on the sealer/UA application. Material and Methods: The pH was measured at 30 min., 3, 24, 72, 168 h. Antibiofilm activity was determined by direct and indirect contact tests (DCT/ICT) on dual-species biofilms (Enterococcus faecalis and Streptococcus oralis). Bacterial survival was assessed by colony-forming unit (CFU) counting. The Mann-Whitney test was applied for th pH analysis whereas the Kruskall-Wallis and Dunn tests were employed for the DCT/ICT evaluations. Results: BCS presented the highest pH at all time points (p<0.05). Related to UA, it significantly reduced the pH at 30 min., 3, 24 and 72 h (p<0.05). In the DCT, a significant reduction in CFUs was observed in the BCS and BCS/ UA groups compared to the control and AHP/UA group. BCS also showed the best results in the ICT (p<0.05). Conclusions: It was concluded that UA reduced pH and did not improve the sealers’ antibiofilm activity. BCS showed the highest pH values and antibiofilm activity

The impact of the addition of iodoform on the physicochemical properties of an epoxy-based endodontic sealer

Due to the low radiopacity of Sealer 26, iodoform is frequently empirically added to this sealer. Thus, the interference of this procedure with the physicochemical properties of Sealer 26 must be evaluated. OBJECTIVE: This study evaluated the influence of the addition of iodoform on setting time, flow, solubility, pH, and calcium release of an epoxy-based sealer. MATERIAL AND METHODS: The control group was pure Sealer 26, and the experimental groups were Sealer 26 added with 1.1 g, 0.55 g or 0.275 g of iodoform. Setting time evaluation was performed in accordance with the ASTM C266-03 speciflcation. The analysis of flow and solubility was in accordance with the ISO 6876-2001 speciflcation. For the evaluation of pH and calcium ion release, polyethylene tubes were filled with the materials and immersed in flasks with 10 ml of deionized water. After 24 h, 7, 14, 21, 28, and 45 days pH was measured. In 45 days, the calcium released was evaluated with an atomic absorption spectrophotometer. RESULTS: The addition of iodoform increased setting time in comparison with pure sealer (P<0.05). As for flow, solubility, and calcium release, the mixtures presented results similar to pure sealer (p>0.05). In the 24 h period, the mixture with 1.1 g and 0.55 g of iodoform showed lower pH than pure sealer and than sealer added with 0.275 g of iodoform (P<0.05). CONCLUSIONS: The iodoform added to Sealer 26 interferes with its setting time and solubility properties. Further studies are needed to address the clinical signiflcance of this interference

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

AbstractObjective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05).Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA

Análise físico-química do MTA e do cimento Portland associado a quatro diferentes radiopacificadores

INTRODUCTION: Mineral Trioxide Aggregate (MTA) is composed of Portland cement (PC), and a radiopacifier (bismuth oxide). OBJECTIVE: To evaluate the setting time, solubility, pH, calcium ion release and radiopacity of pure Portland cement and its association to four radiopacifiers, (Barium sulfate, bismuth carbonate, bismuth oxide and iodoform), and White MTA (Angelus, Londrina, Brazil). MATERIAL AND METHOD: The ratio CP/radiopacifier used was 4:1 by weight (80% Portland cement and 20% radiopacifier). The setting time was evaluated according the specification ADA 57. The solubility was analyzed according to ISO 6876/2001 specification. The pH was evaluated using a digital pHmeter and the release of Ca++ ions by atomic absorption spectrophotometer. The radiopacity was measured in millimeters of aluminum (mm/Al). The results were submitted to ANOVA and Tukey tests using 5% of significance level. RESULT: Barium sulfate did not alter the final setting time of the PC. Observed radiopacity was less than the minimum recommended by ADA 57 and ISO 6876/2001 for CP and CP associated with barium sulfate. The PC associated with iodoform showed solubility above the 3% recommended by ISO 6876/2001. All materials provided alkalinization and promoted calcium ion release. CONCLUSION: Bismuth carbonate and bismuth oxide provided proper initial setting time, solubility, pH, calcium ion release and radiopacity when combined with CP.INTRODUÇÃO: O Mineral Trióxido Agregado (MTA) é composto por cimento Portland (CP) e um radiopacificador (óxido de bismuto). OBJETIVO: Avaliar tempo de presa, solubilidade, pH, liberação de íons Cálcio e radiopacidade do cimento Portland puro ou associado a quatro radiopacificadores (sulfato de bário, carbonato de bismuto, óxido de bismuto e iodofórmio), comparados ao MTA branco (Angelus, Londrina, Brasil). MATERIAL E MÉTODO: A proporção empregada CP/radiopacificador foi de 4:1 em peso, (80% de cimento Portland e 20% de radiopacificador). A especificação 57 da ADA foi usada para avaliação do tempo de presa. A solubilidade foi analisada segundo a especificação ISO 6876/2001. A avaliação do pH foi realizada com peagâmetro digital e a liberação de íons Ca++foi verificada por meio de espectrofotômetro de absorção atômica. A radiopacidade foi determinada em milímetros de alumínio (mm/Al). Os resultados foram submetidos aos testes de Análise de Variância e Tukey, nível de significância 5%. RESULTADO: O sulfato de bário não alterou o tempo de presa final do CP. Radiopacidade inferior ao mínimo recomendado pelas normas da ADA nº 57 e ISO 6876/2001 foi observada para CP e CP associado com sulfato de bário. O CP associado ao iodofórmio apresentou solubilidade acima dos 3% recomendados pela ISO 6876/2001. Todos os materiais proporcionaram alcalinização do meio e promoveram liberação de íons cálcio. CONCLUSÃO: Carbonato de bismuto ou óxido de bismuto proporcionaram tempo de presa inicial, solubilidade, pH, liberação de íons Cálcio e radiopacidade adequados quando associados ao CP.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNESP - Univ Estadual Paulista Faculdade de OdontologiaUFJF - Universidade Federal de Juiz de Fora Faculdade de OdontologiaUSP - Universidade de São Paulo Faculdade de OdontologiaUNESP - Univ Estadual Paulista Faculdade de Odontologi

Analysis of radiopacity, pH and cytotoxicity of a new bioceramic material

AbstractObjective RetroMTA® is a new hydraulic bioceramic indicated for pulp capping, perforations or root resorption repair, apexification and apical surgery. The aim of this study was to compare the radiopacity, pH variation and cytotoxicity of this material to ProRoot® MTA.Material and Methods Mixed cements were exposed to a digital x-ray along with an aluminum stepwedge for the radiopacity assay. pH values were verified after incubation period of 3, 24, 48, 72 and 168 hours. The cytotoxicity of each cement was tested on human periodontal ligament fibroblasts using a multiparametric assay. Data analysis was performed using ANOVA and Tukey’spost hoc in GraphPad Prism.Results ProRoot® MTA had higher radiopacity than RetroMTA®(p0.05) although pH levels of both materials reduced over time. Both ProRoot® MTA and RetroMTA® allowed for significantly higher cell viability when compared with the positive control (p<0.001). No statistical difference was observed between ProRoot® MTA and RetroMTA® cytotoxicity level in all test parameters, except for the ProRoot® MTA 48-hour extract media in the NR assay (p<0.05).Conclusion The current study provides new data about the physicochemical and biological properties of Retro® MTA concerning radiopacity, pH and cytotoxic effects on human periodontal ligaments cells. Based on our findings, RetroMTA® meets the radiopacity requirements standardized by ANSI/ADA number 572, and similar pH values and biocompatibility to ProRoot® MTA. Further studies should be performed to evaluate additional properties of this new material

Biological invasion of European tomato crops by Tuta absoluta: ecology, geographic expansion and prospects for biological control

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato originating from South America. After its initial detection in eastern Spain in 2006, it rapidly invaded various other European countries and spread throughout the Mediterranean basin. If no control measures are taken, then the pest can cause up to 80-100% yield losses in tomato crops in recently invaded areas and may pose a threat to both greenhouse and open-field tomato production. The exceptional speed and extent of T. absoluta invasion have called for studies documenting its biology and ecology, while indicating an urgent need for efficient and sustainable management methods. The development of approaches to manage T. absoluta would be facilitated through a detailed revision of information on this pest in its area of origin. This review combines information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs. These programs, together with a variety of other management tactics, may allow efficient integrated pest management of T. absoluta in Europe and Mediterranean Basin countries. © 2010 Springer-Verlag

Critical review of the threats affecting the building of critical infrastructure resilience

In modern society, critical infrastructures (CIs) resilience has become a critical issue in crisis management and CIs protection. However, various threats/hazards could lead to disruption and failure of developing CIs resilience, which inevitably can lead to negative repercussions to humanity and national economy. In this regard, detailed understanding of the threats/hazards and their impacts are critical to improve a country’s preparedness for unexpected situations such as the COVID-19 pandemic. This paper aims to conduct a critical analysis of the potential threats to governments’ efforts and capacity to build CI resilience. A three-stage systematic review process is adopted and a total of 35 papers are carefully selected. Results show that during the past two decades, researchers’ interest in exploring the threats/hazards in CIs resilience has increased. Further, most of the research publications emanate from the United States and United Kingdom. Lastly, a total of 31 threats/hazards are identified, with the most reported threats/hazards being: (1) natural disasters, (2) ageing and decay, (3) cyber threats, (4) terrorist activities, (5) contamination and (6) cascading failure/threat. The findings of this study provide a solid foundation for future research on developing CIs resilience. Additionally, the findings will inform policy makers and government authorities of the salient threats affecting the building of CIs resilience

Accuracy of apical limit control during retreatment provided by hybrid electronic foraminal locators: a micro-CT study

This study investigated the accuracy and reliability of apical limit control in endodontic retreatment using hybrid endodontic motors.Thirty-six mesial canals of mandibular molars were accessed, and their apical foramina (AF) were standardized to 200 µm. Chemical-mechanical preparation was performed with WaveOne Gold instruments (#20/.07), followed by obturation with gutta-percha and AH Plus cement. After initial preparation, the teeth were divided into three groups (n = 12): Root ZX II (RZX), VDW Gold (VDW) and Tri Auto ZX2 (TRZX), all in rotary kinematics and with AF as the limit (0.0). Exposure was performed in the crown-down direction with ProTaper retreatment instruments using 2.5% NaOCl as an irrigation solution. Before using the instruments, the apexes of the teeth were immersed in alginate. With the auto-stop function activated, the hybrid instruments were calibrated to stop rotating when the desired apical limit was reached. The last instrument was fixed in the canal and a micro-computed tomography scan was performed to determine the distance between the instrument tip and the AF. Data were analyzed using the Kruskal-Wallis and Dunn tests (P<0.05).No significant differences were found between the RZX (0.10 mm), Gold (0.13 mm) and TRZX (0.27 mm) devices; accuracy ranged from 91.70% (RZX and VDW) to 63.63% (TRZX). TRZX had the highest number of readings besides AF.It was concluded that all devices studied were efficient in maintaining the apical limit of instrumentation during endodontic retreatment when taken to the AF