METHODOLOGY: A total of 700 maxillary premolars were examined using CBCT in an Egyptian subpopulation. The number of roots was identified, and root canal configurations were classified according to Vertucci's classification and a new system for classifying root and canal morphology. In addition, the position where roots bifurcated and the levels where canals merged or diverged were identified. Fisher's exact test and independent t-test were used for statistical analysis, and the level of significance was set at 0.05 (P = 0.05).
RESULTS: More than half of maxillary first premolars were double-rooted, and the majority of maxillary second premolars were single-rooted (P
METHODS: 15wt% of zirconia (ZrO2) as well as 30, 35, and 40wt% of beta-tricalcium phosphate (β-TCP) were compounded with PA 12, followed by the fabrication of filament feedstocks using a single screw extruder. The fabricated filament feedstocks were used to print the impact specimens. The melt flow rate, tensile properties of fabricated filament feedstocks, and 3D printed impact properties of the specimens were assessed using melt flow indexer, universal testing machine, and Izod pendulum tester, respectively. The microstructure of selected filament feedstocks and broken impact specimens were analysed using a field emission scanning electron microscope and universal testing machine. Human periodontal ligament fibroblast cells (HPdLF) were used to evaluate the cytotoxicity of the materials by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid) (MTT) assay.
RESULTS: Hybrid ceramics filled PA 12 indicated sufficient flowability for FDM 3D printing. The tensile strength of hybrid ceramics filled PA 12 filament feedstocks slightly reduced as compared to unfilled PA 12. However, the tensile modulus and impact strength of hybrid ceramics filled PA 12 increased by 8%-31% and 98%-181%, respectively. A significant increase was also detected in the cell viability of the developed composites at concentrations of 12.5, 25, 50 and 100mg/ml.
SIGNIFICANCE: The newly developed hybrid ceramics filled PA 12 filament feedstock with improved properties is suitable for an FDM-based 3D printer, which enables the creation of patient-specific craniofacial implant at a lower cost to serve low-income patients.
METHODS: Dentine surfaces were etched with 37% phosphoric acid, bonded with respective in vitro ethanol and acetone adhesives modified with (m/m, 0, 1%, 2% and 3% ribose), restored with restorative composite-resin, and sectioned into resin-dentine slabs and beams to be stored for 24h or 12 months in artificial saliva. Bond-strength testing was performed with bond failure analysis. Pentosidine assay was performed on demineralized ribose modified dentine specimens with HPLC sensitive fluorescent detection. The structural variations of ribose-modified dentine were analysed using TEM and human dental pulpal cells were used for cell viability. Three-point bending test of ribose-modified dentine beams were performed and depth of penetration of adhesives evaluated with micro-Raman spectroscopy. The MMP-2 and cathepsin K activities in ribose-treated dentine powder were also quantified using ELISA. Bond strength data was expressed using two-way ANOVA followed by Tukey's test. Paired T tests were used to analyse the specimens for pentosidine crosslinks. The modulus of elasticity and dentinal MMP-2 and cathepsin K concentrations was separately analyzed using one-way ANOVA.
RESULTS: The incorporation of RB in the experimental two-step etch-and-rinse adhesive at 1% improved the adhesive bond strength without adversely affecting the degree of polymerisation. The newly developed adhesive increases the resistance of dentine collagen to degradation by inhibiting endogenous matrix metalloproteinases and cysteine cathepsins. The application of RB to acid-etched dentine helps maintain the mechanical properties.
SIGNIFICANCE: The incorporation of 1%RB can be considered as a potential candidate stabilizing resin dentine bond.
METHODS: The Bovine Corneal Opacity and Permeability test method (BCOP), OECD Test Guideline 437, was used as an initial step to study the inducing effect of palm-based MES on irreversible eye damage. The second assessment involved the use of reconstructed human corneal-like epithelium test method, OECD Test Guideline 492 using SkinEthic™ Human Corneal Epithelium to study the potential effect of palm-based MES on eye irritancy. The palm-based MES were prepared in 10% solution (w/v) in deionized water and tested as a liquid and surfactant test substances whereby both test conducted according to the liquid/surfactant treatment protocol.
RESULTS: The preliminary BCOP results showed that palm-based MES; C12, C14, C16, C16:18 were not classified as severe eye irritants test substances with in vitro irritancy score between 3 and the threshold level of 55. The second evaluation using SkinEthic™ HCE model showed that palm-based MES; C12, C14, C16, C16:18 and three commercial samples were potentially irritants to the eyes with mean tissue viability ≤ 60% and classified as Category 2 according to United Nations Globally Harmonized System of Classification and Labelling of Chemicals. However, there are some limitations of the proposed ocular irritation classification of palm-based MES due to insolubility of long chain MES in 10% solution (w/v) in deionized water.
CONCLUSION: Therefore, future studies to clarify the eye irritation potential of the palm-based MES will be needed, and could include; methods to improve the test substance solubility, use of test protocol for solids, and/or inclusion of a benchmark anionic surfactant, such as sodium dodecyl sulphate within the study design.
MATERIALS AND METHODS: Sixty-three freshly extracted human maxillary central incisors were used for the study. The teeth were instrumented with K-flex files and obturated using lateral condensation technique with GP and AH Plus sealer. The teeth were divided into three retreatment groups, each group consisting of 21 teeth. Group I: D-RaCe desobturation files (D-RaCe); group II: ProTaper Universal retreatment files (PTUR); group III: Hedstrom files (H-file). After removal of GP, the teeth were split longitudinally and divided into three equal parts: Cervical, middle, and apical third. The middle and apical thirds of all root halves were examined using scanning electron microscope (SEM). The total surface area covered by the residual debris was evaluated using Motic Image plus 2.0 software. Statistical analysis was done by one-way analysis of variance (ANOVA) test with a p-value <0.05 used to determine significance and Tukey's multiple post hoc tests used for comparison between the groups, and 't' test was done for comparison between the thirds within the same group.
RESULTS: The PTUR retreatment files showed overall better performance compared with D-RaCe files and H-files. The PTUR files performed better at middle third compared with others. The PTUR files and D-RaCe files performed equally at apical third better than H-files.
CONCLUSION: ProTaper retreatment files are better compared with D-RaCe files and H-files for the retreatment of the previously endodontically treated teeth.
CLINICAL SIGNIFICANCE: Highest efficacy for the removal of GP was shown by ProTaper Universal System followed by D-RaCe and H-file.
Methods: Colchicine-loaded transethosomes (TEs) were prepared by the cold method and statistically optimized using three sets of 24 factorial design experiments. The optimized formulations were incorporated into Carbopol 940® gel base. The prepared colchicine-loaded transethosomal gels were further characterized for vesicular size, dispersity, zeta potential, drug content, pH, viscosity, yield, rheological behavior, and ex vivo skin permeation through Sprague Dawley rats' back skin.
Results: The results showed that the colchicine-loaded TEs had aspherical irregular shape, nanometric size range, and high entrapment efficiency. All the formulated gels exhibited non-Newtonian plastic flow without thixotropy. Colchicine-loaded transethosomal gels were able to significantly enhance the skin permeation parameters of the drug in comparison to the non-ethosomal gel.
Conclusion: These findings suggested that the transethosomal gels are promising carriers for the transdermal delivery of colchicine, providing an alternative route for drug administration.
METHODS: Upper limb tendons were harvested with consent from patients with crush injuries and non-replantable amputations. These tendons (both extensor and flexor) measuring 1 cm are sutured to either side of a 0.5 cm synthetic tendon strip and cultured in growth medium. At 2, 4, 6 and 8 weeks, samples were fixed into paraffin blocks, cut and stained with haematoxylin-eosin (H&E) and Masson's trichrome.
RESULTS: Minimal tendon ingrowth were seen in the first 2 weeks of incubation. However at 4 weeks, the cell ingrowth were seen migrating towards the junction between the tendon and the synthetic scaffold. This ingrowth continued to expand at 6 weeks and up to 8 weeks. At this point, the demarcation between human tendon and synthetic scaffold was indistinct.
CONCLUSIONS: We conclude that tendon ingrowth composed of collagen matrix were able to proliferate into a synthetic scaffold in vitro.
MATERIALS AND METHODS: Three categories of materials, namely, test group 1 (cGIC or type IX GIC), test group 2 (HA-GIC or hydroxyapatite-added GIC), and positive control (glass cover slips) were incubated with human periodontal ligament fibroblasts. The samples were viewed under scanning electron microscope to study the morphological characteristics of fibroblasts. Additionally, elemental analysis was performed to differentiate between the two test groups based on surface chemical composition.
RESULTS: Test group 1 (cGIC) exhibited cells with curled up morphology, indicative of poor attachment to the substrate. Test group 2 (Ha-GIC) exhibited cells with flattened morphology and numerous cellular extensions such as lamellipodia and blebs, indicative of good attachment to the substrate. The test group 2 (Ha-GIC) demonstrated higher surface elemental percentages of calcium and phosphorus.
CONCLUSION: Within the limitations of this study, it may be concluded that hydroxyapatite-added GIC is more biocompatible than conventional GIC (type IX), probably attributed to high elemental percentages of calcium and phosphorus.
CLINICAL SIGNIFICANCE: The search for an ideal cervical restorative dental material has been ever elusive. Hydroxyapatite-added GIC is a simple and economical dental material to fabricate from basic conventional GIC. The results from this study strengthen its candidature for cervical and root surface restorations which may later require soft tissue augmentation. The possibility of connective tissue adhesion to this material is an exciting prospect in the field of periorestorative dentistry.
MATERIALS AND METHODS: Purified islets were treated with serum-free, serum, IBMX, tocopherol, or IBMX and tocopherol media. Quantitative polymerase chain reaction and Western blotting were carried out to compare the expression levels of PDX1 in treated purified islets cultured with different media.
RESULTS: Islets treated with IBMX/tocopherol exhibited the highest fold change in the relative expression of PDX1 on day 5 post-treatment (relative expression: 6.80±2.08), whereas serum-treated islets showed the lowest fold changes in PDX1 expression on day 5 post-treatment (0.67±0.36), as compared with the expression on day 1 post-treatment. Insulin production and viability tests of purified islets showed superiority of islet at supplemented serum-free media with IBMX/tocopherol compared to other cultures (53.875%±1.59%).
CONCLUSIONS: Our results indicated that supplemented serum-free medium with tocopherol and IBMX enhances viability and PDX1 gene expression compared to serum-added and serum-free media.
RESULT: The recipient transconjugants were resistant to erythromycin, cefpodoxime and were mecA positive. PCR amplification of mecA after mix culture plating on Luria Bertani agar containing 100 μg/mL showed that 75% of the donor and 58.3% of the recipient transconjugants were mecA positive. Additionally, 61.5% of both the donor cells and recipient transconjugants were mecA positive, while 46.2% and 41.75% of both donor and recipient transconjugants were mecA positive on LB agar containing 50 μg/mL and 30 μg/mL respectively.
CONCLUSION: In this study, the direction of transfer of phenotypic resistance as well as mecA was observed to have occurred from the donor to the recipient strains. This study affirmed the importance of horizontal transfer events in the dissemination of antibiotics resistance among different strains of MRSA.