Comparing and studying crack formation during apical cavity preparation using ultrasonic instruments

One of the major goals of periradicular surgery is to create a good apical sea! at the apex. This"nis done by sectioning of 2 to 3mm from the apex, preparation of a class I cavity and filling with a"nbiocompatible material."nThe purpose of this in vitro study was to determine whether ultrasonic units used for root end"npreparations could change the surface & structure of resected root ends, as competed to common"nmethods of retropreparation. Eighty-five extracted single rooted teeth were divided into five similar"ngroups. Then instrumented and filled with lateral condensation method. Then three millimeter of apex"nwas resected, retropreparaiions in two groups were done with low speed handpiece and round V) ^ur"nand cavities in two other groups prepared with the highest power of dentspiay ultrasonic unit with TFI-"n10 tip and in one other group prepared with the highest power of neo sonic ultrasonic unit with diamond"ncoated CT-1 retro tip."nFollowing root resection and retropreparation the surface of resected root ends were examined for the"npresence of any cracks or structural changes on the surface of resected root ends with stereo microscope"n50x."nThe results of this study showed thai high power settings of ultrasonic units can increase the potential of"ncrack formation on resected root surfaces. In conclusion it is better to use low power setting of ultrasonic"nfor retropreparation

Evaiuation of Cracks Propagation in Retroflllings with Cinalloy Amalgam

One of the major goals of preradicular surgery is to create a good apical seal. This can be done by sectioning approximately one third of the apex, preparation of a class I cavity, and filling with a biocompatible material. The purpose of this in vitro study was to compare crack propagation in retro filling with two commercially available amalgams. Thirty-four extracted single rooted teeth were divided into two groups. After instrumentation and filling with Gutta percha by lateral condensation method, three millimeter of apex was resected and retro preparations were done by a low speed hand piece and '/> round bur. Then cavities were filled with cinalloy and luxalloy amalgam in-group "one" and "two" respectively. The surface of resected root ends was examined in two stages, after doing retro preparation and retro filling and the presence of any cracks or structural changes was inspected by stereomicroscope 50x. Regard to number and type of cracks, the result of this study showed that there was no significant difference between cinalloy or luxalloy retro fillings. By considering the conditions of this study, cinalloy amalgam can be used as a retro filling material

Vital pulp therapy in symptomatic immature permanent molars: Report of 3 cases

"nEndodontic treatment of immature permanent teeth accompanies with several issues. The primary goal when treating such teeth is to maintain pulp vitality so that root development can occur normally. Indications and requirements for vital pulp therapy include asymptomatic and reversible pulpitis. Also there are controversial opinions regarding the ultimate clinical treatment of the vital pulp therapy techniques. In this manuscript we report 3 cases of immature symptomatic permanent molars with irreversible pulpitis caused by caries exposure of the pulp that have been undergone vital pulp therapy successfully

Is there any association between urinary metabolites of polycyclic aromatic hydrocarbons and thyroid hormone levels in children and adolescents?

Considering the possible effects of polycyclic aromatic hydrocarbons (PAHs) on thyroid function, the current study aims to investigate the association of PAH urinary metabolites with the level of thyroid hormones in a sample of Iranian children and adolescents. This cross-sectional study was conducted from September 2015 to July 2016 in Isfahan, Iran. Participants were 150 students, aged 6-18 years, who were selected by multistage cluster random sampling from schools of Isfahan province. Blood and urine samples of participants were obtained for measurement of thyroid hormone levels (measured by immunoradiometric assay) and PAH urinary metabolites, including 1-hydroxynaphthalene, 2-hydroxynaphthalene, 9-hydroxyphenanthrene, and 1-hydroxypyrene. The association of serum thyroid-stimulating hormone (TSH) and PAH urinary metabolites was determined by correlation and regression analyses. Multivariate regression analysis revealed significant association between serum TSH and PAH urinary metabolites; this association remained significant after adjustment for gender and age. The corresponding figures were r = 0.85 for 1-naphthol, r = 0.86 for 2-naphthol, r = 0.87 for 1-hydroxypyrene, and r = 0.42 for 9-phenantrol, respectively, all p values < 0.001. The mean levels of 1-hydroxypyrene and 9-phenanthrol were higher in boys than those in girls (p < 0.05). The findings of this study indicated significant positive association between urinary PAH biomarkers and the TSH level in children and adolescents. It can be suggested that long-term exposure to PAHs might result in thyroid function impairment. The clinical implication of the current findings should be confirmed by future longitudinal studies

Recent advances in the analysis of per- and polyfluoroalkyl substances (PFAS) - A review

Per- and polyfluoroalkyl substances (PFAS), that are widely used in different industrial and commercial activities, have become emerging contaminants of concern. Thus, the evaluation of PFAS presence in diverse environmental matrices is of paramount importance, leading to the necessity in development of different types of analytical methods to analyse the trace amounts of PFAS with varying selectivity and sensitivity. Analytical methods that have been advanced and employed for PFAS identification are critically described with their strengths, limitations and future potentials in this review. This review includes, (i) instrument analytical methodologies, mainly focusing on sample preparation, extraction and recovery analysis, (ii) nanoparticle-based sensors, and an app-based smartphone portable sensor, for the monitoring and sensing of PFAS in different environmental matrices. Furthermore, (iii) total oxidisable precursor assay (TOPA), content of total organic fluorine (TOF) as well as total fluorine (TF) are also reviewed, which provide fundamental tools towards achieving precursor quantification and closing mass balance analysis

Preparation of Fe3O4/SiO2/TiO2/PrVO4 nanocomposite in various molar ratios: Investigation on photocatalytic performance on organic contaminate and bacterial environments, and anti-cancer properties

Various SiO2/TiO2 nanoparticles coated on Fe3O4 core and a nanocomposite with PrVO4 were prepared through an ultrasonic-assisted co-precipitation approach. The sample with optimal properties for the photocatalytic degradation of rhodamine-B under visible light (around 55 for degradation in 100 min) was chosen, and its photo-antibacterial effects against gam-positive and negative Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922) under UV�Vis light was evaluated. Also, the cytotoxicity properties on Panc1 cells using the MTT assay studied and its IC50 is about 250 mg/L. Structural, morphological and magnetic characteristics of the nanocomposites were evaluated through XRD, FT-IR, SEM, EDX, MAP, UV�Vis DRS, and VSM tests. The crystalline size of Fe3O4/SiO2/TiO2 nanoparticles and Fe3O4/SiO2/TiO2/PrVO4 were determined to be in the range of 55�75 nm, and 80�100 nm respectively, through SEM tests. XRD results indicated that the nanocomposites were pure and VSM analyses proved that the saturation magnetization of the sample is adequate for its applications. © 2020 Elsevier Lt

Preparation of Fe3O4/SiO2/TiO2/PrVO4 nanocomposite in various molar ratios: Investigation on photocatalytic performance on organic contaminate and bacterial environments, and anti-cancer properties

Various SiO2/TiO2 nanoparticles coated on Fe3O4 core and a nanocomposite with PrVO4 were prepared through an ultrasonic-assisted co-precipitation approach. The sample with optimal properties for the photocatalytic degradation of rhodamine-B under visible light (around 55 for degradation in 100 min) was chosen, and its photo-antibacterial effects against gam-positive and negative Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922) under UV�Vis light was evaluated. Also, the cytotoxicity properties on Panc1 cells using the MTT assay studied and its IC50 is about 250 mg/L. Structural, morphological and magnetic characteristics of the nanocomposites were evaluated through XRD, FT-IR, SEM, EDX, MAP, UV�Vis DRS, and VSM tests. The crystalline size of Fe3O4/SiO2/TiO2 nanoparticles and Fe3O4/SiO2/TiO2/PrVO4 were determined to be in the range of 55�75 nm, and 80�100 nm respectively, through SEM tests. XRD results indicated that the nanocomposites were pure and VSM analyses proved that the saturation magnetization of the sample is adequate for its applications. © 2020 Elsevier Lt