bending resistance and cyclic fatigue resistance of waveone gold reciproc blue and hyflex edm instruments

Abstract Background/purpose Several single-file systems manufactured using different heat treatment and operated by different kinematics have been released. This study compared the bending resistance and cyclic fatigue resistance of three NiTi files, and examined their phase-transformation behavior. Materials and methods WaveOne Gold Primary (WOG), Reciproc Blue R25 (RPB), and HyFlex EDM OneFile (HDM) were tested (N = 40/instrument). A vertical load was applied to a point 3 mm from the tip, and the stress was measured until a displacement of 3 mm. Tests were conducted at either room temperature (RT: 22 °C) or body temperature (BT: 37 °C) (n = 10). Cyclic fatigue resistance tests were performed in an artificial canal, which had a curvature angle of 40° and a 5-mm radius. Tests were conducted at either RT or BT (n = 10). Instruments were operated according to the manufacturers' instructions. Test results were analyzed using the Kruskal–Wallis and the Mann–Whitney tests. Additional three instruments of each brand were subjected to differential scanning calorimetry (DSC). Results At RT the bending resistance of three files were not significantly different. However, at BT the bending resistance of RPB was highest, followed by WOG, and HDM (P  Conclusion HDM presented superior flexibility and cyclic fatigue resistance at BT

Evaluation of cyclic fatigue and bending resistance of coronal preflaring niti file manufactured with different heat treatments

Coronal preflaring NiTi files should possess proper hardness, resistance to fracture and flexibility. This study compared the bending resistance and cyclic fatigue resistance of three orifice preflaring NiTi files. HyFlex EDM Orifice opener (#25/12), HyFlex CM (#25/08) and One Flare (#25/09) were tested (n = 46/instrument). Bending resistance was assessed with the stress when perpendicular displacement was applied to a 3 mm point from the file tip, and was performed at either room temperature (RT, n = 10) or body temperature (BT, n = 10). Cyclic fatigue resistance was tested with an artificial ceramic root canal at RT (n = 10) and BT (n = 10), and the number of cycles to failure (NCF) was obtained. The bending resistance and the NCF results were analyzed by two-way ANOVA and Tukey’s test. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses were performed (n = 3, respectively). HyFlex EDM exhibited the highest bending resistance, followed by One Flare and HyFlex CM (p \u3c 0.05), irrespective of the tested temperature. At RT, HyFlex CM demonstrated the highest NCF (p = 0.001), while HyFlex EDM had the highest NCF at BT (p \u3c 0.001). The tested NiTi files were composed of austenite and martensite according to the DSC and XRD results. HyFlex EDM had the highest bending resistance and NCF measured at BT

Comparison of 0.05% cyclosporine and 3% diquafosol solution for dry eye patients: a randomized, blinded, multicenter clinical trial

Background This study is aim to compare the clinical effectiveness between the two most prominent dry eye disease (DED)-specific eye drops, 0.05% cyclosporine (CN) and 3% diquafosol (DQ). Methods This is a multi-centered, randomized, masked, prospective clinical study. A total of 153 DED patients were randomly allocated to use CN twice per day or DQ six times daily. Cornea and conjunctival staining scores (NEI scale), tear break-up time (TBUT), Schirmer test scores, and ocular surface disease index (OSDI) score were measured at baseline, 4 and 12 weeks after treatment. Results At 12 weeks after treatment, NEI scaled scores were significantly reduced from the baseline by − 6.60 for CN and − 6.63 for DQ group (all P < 0.0001, P = 0.9739 between groups). TBUT and Schirmer values for CN were significantly improved from the baseline at 4 and 12 weeks (P = 0.0034, P < 0.0001 for TBUT, P = 0.0418, P = 0.0031 for Schirmer test). However, for DQ, TBUT showed significant improvement at 12 weeks only (P = 0.0281). Mean OSDI score differences from the baseline to 12 weeks were improved by − 13.03 ± 19.63 for CN and − 16.11 ± 20.87 for DQ, respectively (all P < 0.0001, P = 0.854 between groups). Regarding drug compliance, the mean instillation frequency of CN was less than that of DQ (P < 0.001). There were no statistically significant intergroup differences in safety evaluation. Conclusions The level of improvement regarding NEI, TBUT, and OSDI scores were not significantly different between the two treatment groups. However, with regards to the early improvement of TBUT and patient compliance, patients using CN improved faster and with greater adherence to drug usage than did those treated with DQ. Trial registration KCT0002180, retrospectively registered on 23 December 2016.This study was supported by an unrestricted educational grant from Taejoon Pharm (Seoul, Korea), which affords funding only, but has not any other contribution to our research

Korean teachers' and learners' perceptions of world Englishes

As English has been more and more used all around the world, there has been calling for more inclusion of World Englishes (WEs) in English education. English education in Korea, however, still centers on native speaker models, relatively little research investigating WEs from teachers’ and students’ perspectives. The purpose of this study is, therefore, to explore Korean teachers’ and learners’ perceptions of WEs, building on previous work on WEs. Questionnaires, which included both close-ended and open-ended questions, were designed and given to 51 teachers and 79 students in Korea, together with sample speeches representing different WEs. The questions asked participants’ understanding of WEs, English varieties they had learned, taught, and been exposed to, and their attitudes towards including diverse WEs in English education. The results indicated that the participants, in general, had some knowledge of WEs, had mostly learned, taught, and been exposed to American English, and were positive about incorporating varying WEs in English education although some of them were rather skeptical of the inclusion. Comparing the two groups, the teachers showed a better understanding of WEs, and they were more open to the inclusion. The study concludes that English education in Korea needs to be changed into teaching/learning English as a practical language, and diversify the language, reflecting voices from teachers and students. It also suggests that information on WEs which is widely shared by research literature should also be shared with teachers and students before they make any educational choice regarding WEs

Clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) with imported donor corneas in eyes of Asian patients; endothelium-in versus endothelium-out method

© 2022 Public Library of Science. All rights reserved.Objective We investigated whether (1) imported pre-cut tissue is feasible for Descemet membrane endothelial keratoplasty (DMEK) in eyes of Asian patients, (2) the clinical outcome is comparable between the endothelium-in and endothelium-out methods, and (3) the corneal edema-induced anterior curvature changes may have an effect on the refractive error. Methods The medical records of 32 DMEK patients who underwent either the endothelium-out or endothelium-in method using imported pre-cut grafts with a 3-day pre-cut-to-use time were retrospectively analyzed. Fuchs endothelial dystrophy (37.5%) and bullous keratopathy (62.5%) cases were included. The main clinical outcome measures were graft survival, best corrected visual acuity (BCVA), endothelial cell density (ECD), corneal thickness (CT), and complications. Correlation of the anterior curvature changes with refractive error was analyzed in the DMEK with cataract surgery group. Results The overall survival rate was 71.9%. Final graft failures were caused by rejection, glaucoma, and infection. Visual acuities improved by 89.3%. BCVA better than 20/40 and 20/20 was found in 75% and 28.6% of patients, respectively. The ECDs at 3 months and 1 year were 1400 and 1083 cells/mm2, respectively. The mean survival time, ECD, BCVA, CT, and complication rates were not different between the endothelium-in and endothelium-out methods. A hyperopic shift by +0.42 D was not related to the anterior curvature changes. Conclusion Imported pre-cut tissues with a &lt; 3-day pre-cut-to-use time are feasible for DMEK in the treatment of corneal endothelial edema in eyes of Asian patients, and both endothelium-in and endothelium-out methods appear to be comparatively effective. Edema-induced anterior curvature change may not affect the refractive shift.N

Data_Sheet_1_Risk factors for early graft detachment requiring rebubbling in Descemet membrane endothelial keratoplasty with imported pre-cut donor tissues.docx

Graft detachment is a common and significant complication in Descemet membrane endothelial keratoplasty (DMEK). We investigated the risk factors of graft detachment requiring rebubbling after DMEK using imported pre-cut donor tissues. The medical records of 48 patients who underwent DMEK for Fuchs’ endothelial dystrophy (FED) or bullous keratopathy (BK) at Seoul National University Hospital were retrospectively reviewed. Donor, recipient, and surgical factors were evaluated using univariate and multivariate logistic regression models. Graft detachment requiring rebubbling occurred in 17 (32.7%) eyes. The detachment group exhibited older recipient age (p = 0.006), higher prevalence of diabetes (p = 0.001), and a higher proportion of FED (65%, p = 0.003). Notably, the detachment group demonstrated a significantly lower postoperative 2-h intraocular pressure (IOP) (p = 0.002) and a greater proportion of eyes with IOP <20 mmHg (p < 0.001). Older recipient age (OR 1.08, 95% CI 1.02–1.17), diabetes (OR 23.8, 95% CI 2.61–217), FED surgical indication (OR 6.19, 95% CI 1.74–22.0), lower postoperative 2-h IOP (OR 1.21, 95% CI 1.06–1.38), and postoperative 2-h IOP <20 mmHg (OR 14.0, 95% CI 1.64–119) were associated with increased odds of graft detachment. According to multivariate logistic regression, lower postoperative 2-h IOP (OR 1.23, 95% CI 1.02–1.47) and postoperative 2-h IOP <20 mmHg (OR 25.1, 95% CI 1.05–602) increased the risk of graft detachment. Lower postoperative 2-h IOP, particularly below 20 mmHg, may increase the risk of graft detachment, and diabetes in recipients may pose a higher risk of graft detachment after DMEK.</p

Age-Dependent Distinct Distributions of Dendritic Cells in Autoimmune Dry Eye Murine Model

We investigated whether aging-dependent changes in dendritic cell (DC) distributions are distinct in autoimmune dry eye compared with an aging-related murine model. Corneal staining and tear secretion were evaluated in young and aged C57BL/6 (B6) and NOD.B10.H2b mice (NOD). In the corneolimbus, lacrimal gland (LG), and mesenteric lymph node (MLN), CD11b− and CD11b+ DCs, CD103+ DCs and MHC-IIhi B cells were compared between young and aged B6 and NOD mice. With increased corneal staining, tear secretion decreased in both aged B6 and NOD mice (p &lt; 0.001). In both aged B6 and NOD mice, the percentages of corneolimbal CD11b+ DCs were higher (p &lt; 0.05) than those in young mice. While, the percentages of lymph nodal CD103+ DCs were higher in aged B6 and NOD mice (p &lt; 0.05), the percentages of corneolimbal CD103+ DCs were only higher in aged NOD mice (p &lt; 0.05). In aged NOD mice, the proportions of lacrimal glandial and lymph nodal MHC-IIhi B cells were also higher than those in young mice (p &lt; 0.05). It indicates that corneolimbal or lacrimal glandial distribution of CD103+ DCs or MHC-IIhi B cells may be distinct in aged autoimmune dry eye models compared to those in aged immune competent murine models

Spontaneous regression of congenital corneal opacity

Purpose To determine the incidence of spontaneous regression of congenital corneal opacity (CCO) and identify clinical factors associated with the regression. Methods Medical records and anterior segment photographs were reviewed of 57 eyes in 35 patients with CCO that were not related to congenital glaucoma, tumors, infection, trauma, or metabolic disorders and were followed up without corneal transplantation for longer than one year at Seoul National University Hospital. Spontaneous regression of corneal opacity was defined as a decrease in corneal opacity significant enough for visual axis clearance. Data on demographics, systemic, and ocular characteristics were collected and compared between patients who had spontaneous regression of CCO and those who did not. Results Spontaneous regression of corneal opacity developed in 32 eyes (22 patients, 56.1%) out of 57 CCO eyes (35 patients) at the mean 8.2 +/- 5.4 months of age (the median 6.7 months). Absence of combined ocular anomalies such as iris anomaly, lens opacity, and peripheral corneal vascularization was significantly associated with the regression of opacity. Conclusions Corneal opacity can spontaneously regress in 56.1% of eyes with CCO during the first year of life. Careful follow-up with amblyopia management can be one of treatment options for CCO.N