Metformin is the first-line medication for type 2 diabetes, but it also has a long history of improved outcomes in infectious diseases, such as influenza, hepatitis C, and
assays of zika. In the ...current Covid-19 pandemic, which has rapidly spread throughout the world, 4 observational studies have been published showing reduced mortality among individuals with home metformin use. There are several potential overlapping mechanisms by which metformin may reduce mortality from Covid-19. Metformin's past anti-infectious benefits have been both against the infectious agent directly, as well as by improving the underlying health of the human host. It is unknown if the lower mortality suggested by observational studies in patients infected with Covid-19 who are on home metformin is due to direct activity against the virus itself, improved host substrate, or both.
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 (mm3) 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.
Aims
To compare the accuracy of the clearing technique and cone beam computed tomography (CBCT) in the assessment of root canal configurations using micro‐computed tomography (micro‐CT) imaging ...system as the reference standard.
Methodology
Thirty‐two mesial roots of mandibular first molars, selected on the basis of micro‐CT scans (voxel size: 19.6 μm) and presenting several canal configurations, were evaluated using 2 CBCT scanners (voxels sizes: 120 μm and 150 μm) followed by the clearing technique. Two examiners analysed the data from each method and classified the anatomical configuration of the mesial canal according to Vertucci's system. Data were compared using Fisher's exact and chi‐square tests. Reliability for each assessment was verified by the kappa test, and significance level was set at 5%.
Results
Kappa value indicated a high level of agreement between the examiners. Detection of type I configurations was significantly lower in cleared teeth (P < 0.05), whilst type II root canals were detected in all specimens by both tests (P > 0.05). In mesial roots with variable anatomical configurations, CBCT and the clearing method were significantly less accurate than the reference standard (P < 0.05).
Conclusion
Within the tooth population studied, accuracy of identifying mesial root canal configuration was influenced greatly by the evaluation method and the type of anatomy. Detection of type I configurations in cleared teeth was significantly lower, whilst type II configurations were detected in all specimens by both methods. In mesial roots with variable anatomical configurations, neither CBCT nor clearing methods were accurate for detecting the actual root canal anatomy.
Aim
To use micro‐CT to quantitatively evaluate the amount of residual filling material after using several techniques to remove root fillings with and without ultrasonic activation and to analyse the ...cleanliness of the root canal walls and dentine tubules with scanning electron microscopy (SEM).
Methodology
The root canals of one hundred and eight human mandibular incisors were selected and instrumented with rotary files using the BioRace system up to file size 40, .04 taper. After instrumentation, the teeth were filled using a hybrid technique with gutta‐percha and sealer then divided into three groups according to the method used for removing the root filling: G1‐Reciproc (using only instrument R50), G2‐ProTaper Universal retreatment system and G3‐Manual (hand files and Gates‐Glidden burs). All groups were divided into two subgroups depending on whether ultrasonic agitation was used with the irrigants. Micro‐CT scans were taken before and after removal of the filling material to detect residual material in the canal. After micro‐CT analysis, the roots were cut in half, imaged by SEM and scored based on the amount of surface covered by root filling remnants. The data were analysed statistically using a significance level of 5%.
Results
All groups had retained material in the root canals after instrumentation. The Reciproc method was associated with less retained material than the ProTaper and Manual methods. Ultrasonic activation significantly reduced the amount of residual root filling in all groups (P < 0.05).
Conclusion
None of the instrumentation methods were able to completely remove root filling material. Ultrasonic activation improved the removal of root filling material in all groups.
Objective
The objective of this study is to determine the distribution of adult and pediatric American Board of Obesity Medicine (ABOM) diplomates relative to the prevalence of obesity by US state.
...Methods
Data from the ABOM physician directory were used to determine original specialty and US state. Physicians were labeled as “adult medicine” physicians (i.e., internal medicine, family medicine, or internal medicine and pediatrics), “pediatric medicine” physicians (i.e., pediatrics, family medicine, or internal medicine and pediatrics), and “other physicians” (i.e., surgical specialty, other specialty, or unknown). Prevalence of obesity by state, according to the Centers for Disease Control and Prevention, was used for adults and adolescents in 2017 and for children in 2014. Counts of ABOM‐certified adult medicine physicians and pediatric medicine physicians were conducted relative to obesity prevalence by state.
Results
A total of 2,577 US‐based ABOM‐certified physicians were included (79% from adult medicine, 38% from pediatric medicine, and 15% from other fields). All US states had more than one ABOM‐certified adult medicine physician, although geographic disparities existed in physician availability relative to obesity prevalence. Fewer pediatric medicine ABOM diplomates were available in all states.
Conclusions
Promotion of ABOM training and certification in certain geographic locations and among pediatric physicians may help address disparities in ABOM diplomate availability relative to obesity burden.
Aim
To evaluate the antimicrobial effect of 2.5% sodium hypochlorite alone (NaOCl) and associated with 9% HEBP (NaOCl/HEBP), 2% peracetic acid (PAA) and 2% chlorhexidine (CHX), on the viability of ...Enterococcus faecalis biofilms attached to dentine.
Methodology
Biofilms of E. faecalis were grown on the surface of dentine blocks for 5 days and then exposed to the irrigating solutions for 3 min. Distilled water was used as the control. The total biovolume and the percentage of dead cells of the infected dentine were measured by means of confocal microscopy and the live/dead technique. Nonparametric tests were used to determine statistical differences (P < 0.05).
Results
NaOCl and the NaOCl/HEBP mixture were associated with a significantly greater percentage of dead cells, followed by PAA (P < 0.05). No significant antimicrobial effect of CHX was observed in comparison with the control group. Total biovolume decreased significantly in NaOCl, NaOCl/HEBP and PAA solutions in comparison with the CHX and control groups.
Conclusions
NaOCl alone or associated with HEBP were the most effective irrigant solutions in dissolving and killing E. faecalis biofilms.
Aim
To evaluate the effect of individual and combined use of sodium hypochlorite (NaOCl), etidronate (HEDP) and ethylenediaminetetraacetic acid (EDTA) in tissue dissolution.
Methodology
Sixty ...fragments of bovine muscle tissue were prepared and their weights determined on a precision scale. The samples were then distributed in the following groups (n = 10): G1 – saline solution (control); G2 – 17% EDTA; G3 – 18% HEDP; G4 – 2.5% NaOCl; G5 – mixture of 5% NaOCl + 17% EDTA; and G6 – mixture of 5% NaOCl + 18% HEDP. The specimens in each group were immersed in the solutions for 5, 10 and 15 min and reweighted at each time period. Analysis of variance (anova) and Tukey's multiple‐comparison tests (α<0.05) were applied to identify the intragroup and intergroup differences.
Results
G1, G2, G3 and G5 did not dissolve the organic matter. G4 and G6 significantly reduced the weights of specimens at all periods. Amongst the groups, the difference in ability to dissolve organic matter was greater and significant in the following order G4 = G6 > G5 = G3 = G2 = G1 after 5 min of immersion and G4 > G6 > G5 = G3 = G2 = G1 after 10 and 15 min of immersion.
Conclusion
The only solution capable of dissolving organic matter was NaOCl. In the mixtures analysed, this ability was arrested by EDTA; however, it was minimally affected by the HEDP, proving that this combination, if used during the biomechanical preparation, is able to dissolve of organic matter.
Aim
To evaluate dentine thickness from both distal (‘danger zone’) and mesial (‘safety zone’) aspects of the MB1 and MB2 canals of maxillary first molars at the furcation level using micro‐CT ...imaging.
Methodology
One hundred maxillary first molars with two canals in the MB root were selected from a Brazilian subpopulation and scanned at a resolution of 19.6 μm in a micro‐CT device. From each specimen, two axial cross‐sectioned images were selected at 2 and 3 mm apical to the furcation level of the MB root and evaluated for the smallest dentinal thickness. Measurements were made from the outer perimeter of the MB1 and MB2 canals towards the external root surface from both distal (danger zone) and mesial (safety zone) aspects of the root. The influence of an isthmus was also considered in the analysis, and samples were classified according to the presence or absence of an isthmus in the axial sections. Non‐parametric Wilcoxon signed‐rank tests were used to compare dentinal thickness between MB1 and MB2 canals with a significant level set at 5%. Colour‐coded 3D models of dentine thickness throughout the MB root were created and evaluated qualitatively.
Results
At both levels, median dentine thickness of the MB2 canal was significantly lower in both distal and mesial aspects of the root in comparison with the MB1 canal (P < 0.01). The presence of an isthmus was not a variable that influenced dentinal thickness. Colour‐coded models indicated that dentine thickness was dependent on the cross‐sectional shape of the MB root. At least 50% of the sample had <1 mm of dentine thickness at the danger zone of the MB2 canal.
Conclusions
Danger zones in the MB roots of maxillary first molars were not symmetrical. MB2 canals had less dentine thickness on both aspects of the root compared to the MB1 canal.
Aim
To evaluate apical transportation and centring ability during root canal preparation in mesial root canals of mandibular molars associated with ProTaper Gold (PTG), ProDesign S (PDS), Hyflex CM ...(HCM), Hyflex EDM and ProDesign Logic (PDL).
Methodology
Sixty mandibular first molars with two separate canals in the mesial root were selected after root anatomy pairing by microcomputed tomography (microCT). The teeth were randomly divided into five groups (n = 24); the root canal volume was calculated to ensure sample homogeneity. All the root canals were prepared up to size 25 in accordance with the instructions of each rotary system manufacturer. After root canal preparation, the teeth were scanned by microCT to analyse apical transportation, root canal centralization and the pre‐ and post‐preparation root canal volume at the apical and cervical levels. Kruskal–Wallis and Dunn tests were used for comparisons amongst groups for transportation values. For volume changes, the parametric ANOVA and Tukey’s tests were used
Results
There were no significant differences in apical transportation amongst the rotary systems (P > 0.05). All the systems created apical transportation; values ranging from 0.031 mm (PDL) to 0.072 mm (PTG), and enlargements between 39% (HCM) and 91.1% (PDS) were observed. In relative to cervical transportation, significant differences were observed amongst the systems (P < 0.05). Mean transportation values between 0.07 mm (HCM) and 0.172 mm (PTG) were found, with enlargements between 35.4% (HCM) and 51.5% (PDS).
Conclusion
All the thermally treated systems resulted in similar apical transportation. In the cervical region, the Hyflex CM and Prodesign Logic systems were associated with more centred preparations.
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