Curing characteristics of flowable and sculptable bulk-fill composites
Objectives The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites. Materials and methods Six specimens per group, consisting of Tetric EvoCeram Bulk Fill (BTEC Bulk,^ Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement (BSDR,^ Dentsply), Xenius base (BXenius,^ StickTech; commercialized as EverX Posterior, GC), Filtek Bulk Fill flowable (BFiltek Bulk,^ 3M ESPE), and Tetric EvoCeram (BTEC,^ control), were prepared for DC and VH: two 2-mm-thick layers, each light-cured for 10 s; one 4-mm bulk-fill, lightcured for 10 or 20 s; and one 6-mm bulk-fill, cured for 20 s. DC was measured using a Fourier-transform infrared spectrometer, VH using a Vi ckers hardness tester. DoC and TP were measured using an acetone-shaking test and a spectrophotometer, respectively. Data were analyzed using ANOVA and Pearson’s correlation (α = 0.05). Results DC and VH ranged between 40–70 % and 30– 80 VHN, respectively. TEC Bulk, Xenius, and SonicFill, bulk-filled as 4-mm-thick specimens, showed bottom-to-top hardness ratios above 80 % after 20 s curing. A positive linear correlation was found for bottom DC and VH. An average DC ratio of 0.9 corresponded to a bottom-to-top VH ratio of 0.8. Conclusions Sculptable bulk-fills require 20 s, whereas 10 s curing time was sufficient for flowable bulk-fills using a highintensity LED unit. Clinical relevance Clinicians should be aware that longer curing times may be required for sculptable than flowable bulkfill composites in order to achieve optimal curing characteristics.
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Corneal Decompensation in Uveitis Patients: Incidence, Etiology, and Outcome
Purpose: To identify the prevalence, etiology, management and visual outcomes of treatment in uveitisrelated corneal decompensation. Patients and methods: This is a retrospective study of patients with corneal decompensation identified from a large cohort with uveitis in a tertiary referral clinic setting. Results: Between March 1991 and May 2018, 4132 new patients with uveitis were seen in Manchester Uveitis Clinic. Of these, 25 patients (0.6%) were identified with corneal decompensation of which 9 (0.2%) were affected bilaterally (total 34 eyes). The mean interval between uveitis diagnosis and decompensation was 23 months (range 0-117 m). Ten patients (41%) had associated glaucoma. Seventeen eyes (50%) had undergone intraocular surgery prior to decompensation. For eyes with no history of r aised intraocular pressure or intraocular surgery, keratouveitis (presumed autoimmune or tuberculous) was the most common cause of corneal decompensation. Fourteen eyes (41%) required corneal graft and of these, five required repeat grafting. Conclusions: Corneal decompensation in eyes with uveitis is a rare but significant complication. Direct endothelial inflammation may alone cause decompensation, but in most eyes with uveitis, prior raised intraocular pressure or intraocular surgery are required to precipitate the cornea into decompensation. Outcomes of corneal transplantation in this group may be disappointing. ARTICLE HISTORY Received 3 April 2019 Revised 25 September 2019 Accepte
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Green synthesis of silver nanoparticles from waste Vigna mungo plant and evaluation of its antioxidant and antibacterial activity
The development of nanoparticles by using bioresources has become a good practice recently to avoid hazardous chemicals and processes. The present study reports the synthesis of silver nanoparticles by using an alkaline food additive prepared from Vigna mungo plant waste ash. This food additive called “Khar” is very popular in Assam, a North-Eastern state of India. This additive was used as the reducing and stabilizing agent for the synthesis of silver nanoparticles which were then characterized using TEM, XRD, UV–visible spectroscopy, DLS and zeta potential study, FESEM, and EDX. To study the antioxidant activity of the silver nanoparticle and plant waste ash extract, phytochemical analysis was done using standard methods. The quantitative phytochemical ana lysis revealed the presence of phenolic and flavonoid compounds in the aqueous extract of the Vigna mungo ash which was responsible for the strong antioxidant activity of both ash extracts (IC50 = 27.83 µg/mL) and silver nanoparticles (IC50 = 13.74 µg/mL). The agar well diffusion method was used for the analysis of the antibacterial activity of silver nanoparticles which showed remarkable antibacterial activity against both the gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli) respectively. Thus, the study reveals the utility of a traditional food additive made of Assam in the synthesis of silver nanoparticle with notable antioxidant and antibacterial activity.
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C URRENT O PINION Spontaneous breathing trials: how and for how long?
(Abstract not found) Download PDF: https://jawap.eu.org/LoLHa0
