Effects of an Acidic Environment on the Strength and Chemical Changes of Resin-based Composites.

The objective of this study was to evaluate the aging effects of long-term exposure to acidic beverages on the flexural strength (FS) and chemical reactions of two resin-based composites (RBCs) and one giomer. The FS of composite specimen bars (2 mm × 2 mm × 25 mm) was measured using a universal testing machine at various levels of thermocycling (TC; 0, 10,000, 50,000, and 100,000 cycles) in two beverages with different pH values (distilled water [DW], pH 7.0; Coca-Cola, pH 2.4-2.8). The FS data were analyzed using three-way analysis of variance with the post hoc Tukey test and t-test at a significance level of a=0.05. In DW, the FS of an RBC and a giomer did not decrease until 10,000 cycles. The other RBC, Z250, decreased rapidly until 50,000 cycles (p<0.05), followed by no additional decrease until 100,000 cycles. In Coca-Cola, the FS of two RBCs and a giomer decreased more rapidly than in DW from 10,000 cycles (t-test, p<0.05). In Coca-Cola, the increased porosity observed in scanning electron microscopy (SEM) images, the changes of the hydroxyl peak at 3340 cm-1 and ester peak at 1730-1700 cm-1 in Fourier-transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR) spectra, and the continuous increase of the Si-O/Si-C peak height ratio from 10,000 cycles to 100,000 cycles in X-ray photoelectron spectroscopy (XPS) suggested an increased loss of silane-carbon bond between the matrix and fillers of the Z250 RBC, compared to those in DW. In conclusion, when TC was performed in DW, unreacted monomers and a coupling agent were washed out, which caused porosity and reduced FS. In Coca-Cola, acidic conditions accelerated the removal of the matrix through the hydrolysis reaction at the ester groups, resulting in more porosity and a faster decrease in FS than in DW.

Association between body mass index and stroke severity in acute ischaemic stroke with non-valvular atrial fibrillation.

BACKGROUND AND PURPOSE: The objective of this study was to investigate the association between body mass index (BMI) and both initial stroke severity at presentation and functional outcomes after acute ischaemic stroke (AIS) in patients with non-valvular atrial fibrillation (NVAF). METHODS: Patients were categorized on the basis of their BMI into underweight (BMI <18.5, n = 111), normal (18.5 ≤ BMI <25, n = 1036) and overweight to obese (BMI ≥25, n = 472) groups. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) score and functional outcomes were assessed using the modified Rankin Scale score at discharge. The differences in stroke severity and functional outcomes were compared between groups using robust log-linear regression with a Poisson distribution and binary logistic regression analysis. RESULTS: A total of 1619 AIS patients with NVAF from six hospitals were included. Compared with the NIHSS scores [median 5, interquartile range (IQR) 2-14] of normal-weight patients, the NIHSS scores (median 9, IQR 4-19) of underweight patients were more likely to be higher, whereas those of overweight to obese patients were lower (median 4, IQR 1-12) (P < 0.001). In terms of functional outcomes after stroke, underweight patients had a higher risk of poor functional outcomes (odds ratio 1.78, 95% confidence interval 1.09-2.56, P = 0.01) but overweight to obese patients had no significant difference in functional outcomes compared with normal-weight patients. CONCLUSION: An inverse association was found between BMI and stroke severity in AIS patients with NVAF. This suggests the presence of an obesity paradox for short-term outcomes in patients with NVAF.

Association between time to treatment and functional outcomes according to the Diffusion-Weighted Imaging Alberta Stroke Program Early Computed Tomography Score in endovascular stroke therapy.

BACKGROUND AND PURPOSE: The rate at which the chance of a good outcome of endovascular stroke therapy (EVT) decays with time when eligible patients are selected by baseline diffusion-weighted magnetic resonance imaging (DWI-MRI) and whether ischaemic core size affects this rate remain to be investigated. METHODS: This study analyses a prospective multicentre registry of stroke patients treated with EVT based on pretreatment DWI-MRI that was categorized into three groups: small [Diffusion-Weighted Imaging Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS)] (8-10), moderate (5-7) and large (<5) cores. The main outcome was a good outcome at 90 days (modified Rankin Scale 0-2). The interaction between onset-to-groin puncture time (OTP) and DWI-ASPECTS categories regarding functional outcomes was investigated. RESULTS: Ultimately, 985 patients (age 69 ± 11 years; male 55%) were analysed. Potential interaction effects between the DWI-ASPECTS categories and OTP on a good outcome at 90 days were observed (Pinteraction  = 0.06). Every 60-min delay in OTP was associated with a 16% reduced likelihood of a good outcome at 90 days amongst patients with large cores, although no associations were observed amongst patients with small to moderate cores. Interestingly, the adjusted rates of a good outcome at 90 days steeply declined between 65 and 213 min of OTP and then remained smooth throughout 24 h of OTP (Pnonlinearity  = 0.15). CONCLUSIONS: Our study showed that the probability of a good outcome after EVT nonlinearly decreased, with a steeper decline at earlier OTP than at later OTP. Discrepant effects of OTP on functional outcomes by baseline DWI-ASPECTS categories were observed. Thus, different strategies for EVT based on time and ischaemic core size are warranted.

Associations of various blood pressure parameters with functional outcomes after endovascular thrombectomy in acute ischaemic stroke.

BACKGROUND AND PURPOSE: High blood pressure (BP) at presentation is associated with poor outcomes in acute ischaemic stroke, but serial BP measurements may better delineate the clinical implications of BP. The aim was to investigate the association between various BP parameters and functional outcomes in acute ischaemic stroke patients treated with endovascular thrombectomy (EVT). METHODS: This study reports a retrospective analysis of a prospective registry of a comprehensive stroke centre. Patients treated with EVT due to large vessel occlusion in the anterior circulation were enrolled. BP was measured hourly during the first 24 h after admission. Associations of various BP parameters, including BP variability, with functional outcomes at 3 months, including good outcomes (modified Rankin Scale score of 0-2), were analysed. RESULTS: Of the 378 enrolled patients (mean age 70 ± 11 years, male 54.2%), 313 (82.8%) achieved successful reperfusion after EVT, and 149 (39.4%) had good outcomes at 3 months. Higher mean systolic BP [each 10 mmHg increase, odds ratio 0.82 (0.69-0.97)] and higher systolic successive variation (SV) [each 10% increase, odds ratio 0.37 (0.18-0.76)] were associated with a reduced likelihood of achieving good outcomes. In addition, reperfusion status after EVT moderated the influence of higher systolic SV on good outcomes (Pint  = 0.05). CONCLUSION: The results showed that a higher mean systolic BP and systolic SV during the first 24 h of EVT reduced the likelihood of good outcomes at 3 months. The effects of these parameters on outcomes are more substantial amongst patients with successful reperfusion after EVT, suggesting that different BP control strategies should be employed according to reperfusion status.

The Survival of Class V Composite Restorations and Analysis of Marginal Discoloration.

The aims of this retrospective clinical study were to analyze the longevity of class V composite restorations and compare the results obtained from clinical and laboratory evaluation of marginal discoloration. A total of 186 restorations were evaluated with modified US Public Health Service criteria. Longevity and associated variables were analyzed with the Kaplan-Meier method and a Cox proportional hazard model. Restorations with marginal discoloration were additionally evaluated using digital photographs and epoxy resin replicas under a stereomicroscope. The mean survival time was 15.0 years, with five- and 10-year survival rates of 95.5% and 83.1%, respectively. Z250 had a higher risk of failure (hazard ratio=7.01, 95% confidence interval=2.07-23.72) than Z100. In addition, the presence of occlusal wear facets and bleeding on probing were associated with an increased risk of failure of the restorations. However, the use of an adhesive system (Scotchbond Multi-Purpose or Clearfil SE Bond) did not affect the longevity of the restorations. The results of laboratory evaluation were significantly different from clinical evaluation (p<0.001, McNemar test). Among 55 restorations rated as Bravo in the clinical evaluation, 24 restorations (43.6%) were determined to have penetrating discoloration on laboratory evaluation. When evaluating aged composite restorations, surface refurbishment and the use of a microscope are recommended, which will be helpful in determining the need for timely repair or replacement.

Effects of multipurpose, universal adhesives on resin bonding to zirconia ceramic.

This study evaluated the effects of single-bottle, multipurpose, universal adhesives on the bond strength of resin cement to zirconia ceramic. Polished zirconia ceramic (Cercon base) discs were randomly divided into four groups (n=40) according to the applied surface-conditioning agent: Single Bond 2, Single Bond Universal, All-Bond Universal, and Alloy Primer. Cured composite cylinders (Ø 0.8 mm × 1 mm) were cemented to the conditioned zirconia specimens with resin cement (RelyX ARC). The bonded specimens were subjected to a microshear bond-strength test after 24 hours of water storage and after 10,000 cycles of thermocycling. The surface-conditioning agent significantly influenced the bond strength (p<0.05). Single Bond Universal showed the highest initial bond strength (37.7 ± 5.1 MPa), followed by All-Bond Universal (31.3 ± 5.6 MPa), Alloy Primer (26.9 ± 5.1 MPa), and Single Bond 2 (8.5 ± 4.6 MPa). Artificial aging significantly reduced the bond strengths of all the test groups (p<0.05). After 10,000 cycles of thermocycling, All-Bond Universal showed the highest bond-strength value (26.9 ± 6.4 MPa). Regardless of artificial aging, Single Bond Universal and All-Bond Universal showed significantly higher bond strengths than Alloy Primer, a conventional metal primer.

The effect of sandblasting and different primers on shear bond strength between yttria-tetragonal zirconia polycrystal ceramic and a self-adhesive resin cement.

PURPOSE: To evaluate the effect of zirconia primers, air-abrasion, and tribochemical surface treatment methods on the shear bond strength between yttria-tetragonal zirconia polycrystal (Y-TZP) ceramic and self-adhesive resin cement. METHODS AND MATERIALS: Y-TZP ceramic surfaces were ground flat with 600-grit silicon carbide paper and then divided into seven groups of 10 and treated as follows: untreated (control), Monobond Plus, Z-PRIME Plus, ESPE Sil with CoJet, air-abrasion, Monobond Plus with air-abrasion, and Z-PRIME Plus with air-abrasion. Self-adhesive resin cement was placed onto the treated Y-TZP specimens for each group. All specimens were thermocycled and subjected to a shear bond strength test. Scanning electron microscope images of the fractured areas and x-ray diffraction (XRD) analysis of the surface-treated Y-TZP specimens were performed. Data were statistically analyzed using one-way analysis of variance and the Student-Newman-Keuls multiple comparison test (p<0.05). RESULTS: The Z-PRIME Plus treatment in combination with air-abrasion produced the highest bond strength (16.50±2.26 MPa), followed by air-abrasion (10.56±3.32 MPa), and then Monobond Plus combined with air-abrasion (8.93±3.13 MPa), ESPE Sil after CoJet application (8.54±3.98 MPa), and the Z-PRIME Plus group (8.27±2.79 MPa). The control (3.91±0.72 MPa) and Monobond Plus (4.86±1.77 MPa) groups indicated the lowest results (p<0.05). The XRD results showed the peaks of the monoclinic phase for the air-abrasion and CoJet treatment groups compared with the Y-TZP control. CONCLUSION: Z-PRIME Plus primer application after air-abrasion presented the best results for improving the bond strength between Y-TZP ceramic and self-adhesive resin cement.

The skeletal maturation status estimated by statistical shape analysis: axial images of Japanese cervical vertebra.

OBJECTIVES: To evaluate axial cervical vertebral (ACV) shape quantitatively and to build a prediction model for skeletal maturation level using statistical shape analysis for Japanese individuals. METHODS: The sample included 24 female and 19 male patients with hand-wrist radiographs and CBCT images. Through generalized Procrustes analysis and principal components (PCs) analysis, the meaningful PCs were extracted from each ACV shape and analysed for the estimation regression model. RESULTS: Each ACV shape had meaningful PCs, except for the second axial cervical vertebra. Based on these models, the smallest prediction intervals (PIs) were from the combination of the shape space PCs, age and gender. Overall, the PIs of the male group were smaller than those of the female group. There was no significant correlation between centroid size as a size factor and skeletal maturation level. CONCLUSIONS: Our findings suggest that the ACV maturation method, which was applied by statistical shape analysis, could confirm information about skeletal maturation in Japanese individuals as an available quantifier of skeletal maturation and could be as useful a quantitative method as the skeletal maturation index.

Axial cervical vertebrae-based multivariate regression model for the estimation of skeletal-maturation status.

OBJECTIVES: This study aimed to determine the viability of using axial cervical vertebrae (ACV) as biological indicators of skeletal maturation and to build models that estimate ossification level with improved explanatory power over models based only on chronological age. MATERIALS AND METHODS: The study population comprised 74 female and 47 male patients with available hand-wrist radiographs and cone-beam computed tomography images. Generalized Procrustes analysis was used to analyze the shape, size, and form of the ACV regions of interest. The variabilities of these factors were analyzed by principal component analysis. Skeletal maturation was then estimated using a multiple regression model. RESULTS: Separate models were developed for male and female participants. For the female estimation model, the adjusted R(2) explained 84.8% of the variability of the Sempé maturation level (SML), representing a 7.9% increase in SML explanatory power over that using chronological age alone (76.9%). For the male estimation model, the adjusted R(2) was over 90%, representing a 1.7% increase relative to the reference model. CONCLUSIONS: The simplest possible ACV morphometric information provided a statistically significant explanation of the portion of skeletal-maturation variability not dependent on chronological age. These results verify that ACV is a strong biological indicator of ossification status.

Prediction of hemorrhagic transformation in acute ischaemic stroke by micro- and macroalbuminuria after intravenous thrombolysis.

BACKGROUND AND PURPOSE: Hemorrhagic transformation (HT) is one of the most problematic complications to arise from intravenous thrombolysis (IVT). This study was conducted to assess whether micro- and macroalbuminuria could be associated with HT after IVT in patients with acute ischaemic stroke, and to investigate whether the value of urinary albumin-to-creatinine ratios would correlate with the degree of HT. METHODS: This was a retrospective study of stroke patients who had undergone IVT within 3 h of symptom onset. Albuminuria assessment was based on random morning spot urine collection with patients in a fasting state, the first morning after IVT. Multiple logistic regression analysis was used to evaluate whether the presence of micro- and macroalbuminuria might be independent predictors of HT. RESULTS: One-hundred and fifty-four patients were included in the study. Fifty-one patients had HT. The presence of micro- or macroalbuminuria was associated with HT after adjustment for variables with clinical significance (adjusting for age, atrial fibrillation, platelet counts, baseline National Institutes of Health Stroke Scale score, hypertension and diabetes mellitus; odds ratio, 2.542; 95% confidence interval, 1.106-5.841; P = 0.028). There were significant relationships between the presence of micro- and macroalbuminuria and types of HT. CONCLUSION: In conclusion, the results of this study suggest that the presence of micro- and macroalbuminuria after IVT could be a predictor of severe HT in patients with acute ischaemic stroke.

Longevity of direct restorations in stress-bearing posterior cavities: a retrospective study.

The aims of this retrospective clinical study were to compare the longevities of direct posterior amalgam restorations (AMs) and resin composite restorations (RCs) that were subjected to occlusal stresses and to investigate variables predictive of their outcome. A total of 269 AMs and RCs filled in Class I and II cavities of posterior teeth were evaluated with Kaplan-Meier survival estimator and multivariate Cox proportional hazard model. Seventy-one retreated restorations were reviewed from dental records. The other 198 restorations still in use were evaluated according to modified US Public Health Service (USPHS) criteria by two investigators. The longevity of RCs was significantly lower than that of AMs (AM = 8.7 years and RC = 5.0 years, p<0.05), especially in molars. The prognostic variables, such as age, restorative material, tooth type, operator group, diagnosis, cavity classification, and gender, affected the longevity of the restorations (multivariate Cox regression analysis, p<0.05). However, among the restorations working in oral cavities, their clinical performance evaluated with modified USPHS criteria showed no statistical difference between both restoratives. In contrast to the short longevity of RCs relative to AMs, the clinical performance of RCs working in oral cavities was observed to be not different from that of AMs. This suggests that once a RC starts to fail, it happens in a rapid progression. As posterior esthetic restorations, RCs must be observed carefully with periodic follow-ups for early detection and timely repair of failures.

Right-to-left shunts as a cause of juxtacortical spots in patients with migraine.

BACKGROUNDS: Juxtacortical spots on fluid-attenuated inversion recovery (FLAIR) images can be frequently detected in patients with migraine. However, the origins of the cerebral lesions (including juxtacortical spots on FLAIR images) found in the previous studies are not known. We sought to investigate the association between juxtacortical spots on FLAIR images and right-to-left shunt (RLS) in migraine patients. METHODS: Juxtacortical spots on FLAIR images were arbitrarily defined as small areas of hyperintensities in the juxtacortex and cortico-subcortical junction. The presence of RLS was examined by a transcranial Dopper (TCD) with the agitated saline test. The degree of RLS was categorized into four grades according to the number of microemboli: no shunt, <10 microbubbles (MB), >10 MB single spots pattern, and >10 MB shower/curtain pattern. We compared the results for migraine patients (n = 49) with those for healthy controls (n = 49). RESULTS: Juxtacortical spots on FLAIR images occurred in 38/98 subjects; of them, 27/49 (55.1%) had migraines and 11/49 (22.2%) were healthy controls (P = 0.002). The independent factors associated with juxtacortical spots on FLAIR images were female, migraine patients, and RLS by multivariate analysis. In migraine patients, RLS was independently associated with juxtacortical spots on FLAIR images. CONCLUSION: Our results suggest that juxtacortical spots on FLAIR images were frequently found in migraine patients and might be associated with the presence of RLS in those patients. Further studies are needed to assess whether juxtacortical spots have clinical implications in patients with migraine.

Cone-beam computed tomography evaluation of short- and long-term airway change and stability after orthognathic surgery in patients with Class III skeletal deformities: bimaxillary surgery and mandibular setback surgery.

The purpose of this study was to evaluate the volumetric change of the upper airway space in 36 Class III patients who had undergone bimaxillary surgery or isolated mandibular setback, and, further, to analyse the relation between post-surgical stability and airway change using cone-beam computed tomography (CBCT). A three-dimensional (3D) CBCT examination was performed at three stages: T0 (before surgery), T1 (an average of 4.6 months after surgery), and T2 (an average of 1.4 years after surgery). The results showed that the volumes of the oropharyngeal and hypopharyngeal airways decreased significantly 4.6 months post-surgery in the mandibular setback group (p<0.05), and these diminished airways had not recovered 1.4 years post-surgery. In the bimaxillary surgery group, the volume of the oropharyngeal airway also decreased. A Spearman correlation analysis showed that the anteroposterior length of the hypopharyngeal area had a correlation with post-surgical stability in the isolated mandibular surgery group, and that the cross-sectional area of the nasopharynx was correlated with maxillary relapse only in the bimaxillary surgery group (p<0.05).

The assessment of the short- and long-term changes in the condylar position following sagittal split ramus osteotomy (SSRO) with rigid fixation.

The purpose of this study was to compare the short- and long-term changes in condylar position related to the glenoid fossa, and skeletal and occlusal stability after orthognathic surgery. All of the study patients were assessed by cone-beam computed tomography images for condylar rotational changes and anteroposterior position in the pre-surgery, post-surgery and post-retention period. The condylar positions were evaluated on three planes: axial, coronal and sagittal. In the skeletal and occlusal measurements, there was no significant difference between the post-surgery group and the post-retention group. After sagittal split ramus osteotomy (SSRO), the condyle on the axial plane rotated inward (P < 0.05) and maintained during the post-retention period. In the anteroposterior condylar position related to the glenoid fossa, the condyles had changed from the anterior position in the pre-surgery group to a concentric position in the post-surgery group and then returned to the anterior position in the post-retention groups. These results suggested that the changed anteroposterior condylar position in the glenoid fossa after SSRO with rigid fixation had moved from a concentric to anterior position for post-retention period.

Antioxidant nutrient intakes and corresponding biomarkers associated with the risk of atopic dermatitis in young children.

BACKGROUND/OBJECTIVES: To investigate the association of antioxidant nutritional status with the risk of atopic dermatitis (AD) in young children in a case-control, population-based study. SUBJECTS/METHODS: Identified from preschools by using the Korean version of the International Study of Asthma and Allergies in Childhood (ISAAC). Final analysis included 180 AD (mean age 5.3+/-0.9 years) and 242 non-AD (mean age 5.2+/-1.0 years) children. Diet was assessed using a validated semi-quantitative food frequency questionnaire. Fasting blood samples were used for analyses of fat-soluble vitamins (retinol, alpha-tocopherol, and beta-carotene) and vitamin C. RESULTS: AD was associated negatively with intakes of antioxidant-related nutrients. The adjusted odds ratio (OR) and 95% confidence interval (95% CI) were 0.44 (0.22-0.88) for the highest (vs lowest) quintile of beta-carotene. A similar association was observed for dietary vitamin E (OR=0.33, 95% CI=0.16-0.67), folic acid (OR=0.37, 95% CI=0.18-0.73), and iron (OR=0.39, 95% CI=0.19-0.79). Reduced AD risk was found with 1 s.d. increase of serum alpha-tocopherol [OR=0.64, 95% CI=0.41-0.98) and retinol (OR=0.74, 95% CI=0.58-0.96) concentrations, and marginally with that of serum beta-carotene levels (P=0.0749 for trend). There was no relationship of AD risk with dietary and plasma vitamin C as well as nutrient supplement intake regardless of nutrient type. AD was predicted better by the intake measure than the corresponding blood biomarker regarding vitamin E and beta-carotene. CONCLUSIONS: These findings suggest that higher antioxidant nutritional status reduces the risk of AD and that such risk-reduction effects depend on nutrient type.

A 6-month, multicenter, single-arm pilot study to evaluate the efficacy and safety of generic tacrolimus (TacroBell) after primary renal transplantation.

OBJECTIVE: Tacrolimus has been shown to be an important immunosuppressive agent in organ and bone marrow transplantation. Previously, we reported that there were no statistically significant differences between the pharmacokinetic parameters of the oral formulation of generic tacrolimus (TacroBell) and the conventional formulation (Prograf). This study was designed to evaluate the efficacy and safety of oral capsules of TacroBell in de novo renal transplantation. METHODS: Ninety-six renal transplant recipients from 9 transplantation centers in South Korea were enrolled between November 2005 and July 2007. De novo renal recipients ranged from 19-65 years old. Ninety-four patients who underwent renal transplantation were administered study drug at least one time in the intent-to-treat (ITT) analysis. This phase 4 clinical trial was a 26-week, open-label, noncomparative, multicenter study. RESULTS: An acute rejection episode developed in 10/94 recipients (10.6%, 95% confidence interval, 4.4%-16.9%). There were no patient deaths during the study. The 6-month graft survival rate was 96.8%. CONCLUSION: Based on this study, treatment with TacroBell is considered to be efficient and safe after primary renal transplantation.

Sensitivity of plasma membrane H+-ATPase of cucumber root system in response to low root temperature.

Cucumber plants (Cucumis sativus L.) were grown at different root temperatures and the H+-ATPase activities in the root plasma membranes were investigated. Electrolyte leakages and the amount of water transported from root to shoot indicated the sensitivity of cucumber root systems to low root temperature. The increase in H+-ATPase activity after 1 day of low root temperature treatment was reversed and gradually diminished as root temperatures of 10 °C continued for another 6 days. The H+-transport rate of the plasma membranes and the transcriptional activity of the corresponding gene expression closely followed the H+-ATPase activity. The role of H+-ATPase in root plasma membranes in terms of the root acclimation process at low root temperature is discussed.

Characterization of a glutathione S-transferase gene ATGST 1 in Arabidopsis thaliana.

A glutathione S-transferase (GST) gene was cloned in Arabidopsis thaliana. The gene, designated ATGST 1, contained the entire transcription unit in three exons interrupted by two introns. The combined sequence of three exons had an open reading frame which predicted a GST protein of 208 amino acids. Gene transcription has been reported to be induced by pathogen attack and dehydration. In the present study northern blot analysis using a gene-specific DNA probe in the 3' untranslated region revealed that expression of the gene was also rapidly induced by other environmental stresses such as wounding, low temperature, high salt and DPE herbicide treatment. The promoter region of the gene contained the sequence motif ATTTCAAA that is known to be present in ethylene-responsive elements and other motifs that are highly conserved amongst stress-inducible gene promoters.