Clinical effect of chlorhexidine and sodium fluoride on corrosion behavior and surface topography of nitinol orthodontic archwires.

BACKGROUND: Alterations in the mechanical properties of the materials utilized in orthodontic appliances could affect the working properties of the appliances, thereby affecting clinical progress and outcome. Numerous studies have confirmed the correlation between alloy corrosion and raised surface roughness, which has a direct impact on the working characteristics of orthodontic archwires. METHODS: Thirty nickel-titanium (NiTi) orthodontic archwires were utilized in this study. Patients were randomly selected and allocated into three groups according to the randomization plan; (The control group): subjects practiced regular oral hygiene; (The fluoride group): subjects used fluoride for intensive prophylaxis; (The chlorhexidine group): subjects used chlorhexidine. Representative samples were evaluated by SEM, and then SEM images with high resolution were examined using Image J software to determine the surface roughness and obtain the results for further statistical analysis. RESULTS: Our findings indicated a significant difference was found between the three groups regarding the anterior and posterior parts between the control and the two other groups and a non-significant difference between NaF and CHX groups. Overall, the p-value for group comparisons was 0.000 for both parts, indicating a highly significant difference especially between the control and NaF groups. CONCLUSION: Mouthwashes containing sodium fluoride demonstrated more significant surface alterations than the control and CHX groups and should be prescribed in accordance with orthodontic materials to reduce side effects.

The epidemiological and clinicopathological characteristics of multifocal/multicentric breast cancer in the Egyptian Delta and its impact on management strategies.

BACKGROUND: Multifocal (MFBC)/multicentric (MCBC) breast cancer is being more recognized due to the improved imaging modalities and the greater orientation with this form of breast cancer, however, optimal surgical treatment, still poses a challenge. The standard surgical treatment is mastectomy, however, breast-conserving surgeries (BCS) may be appropriate in certain situations. METHODS: A total of 464 cases of MF/MCBC out of 4798 cases of breast cancer were retrospectively analyzed from the database of the Oncology Center, Mansoura University (OCMU), between January 2008 and December 2019. RESULTS: Radiologic involvement of multiple quadrants was reported in 27.9% by ultrasonography, 19% by mammography, and 59.1% by magnetic resonance imaging. BCS was performed in 32 cases (6.9%) while 432 cases underwent a mastectomy. Postoperative pathology revealed infiltration of other quadrants grossly in 23.5%, and under the microscope in 63.6% of the examined cases. Mean disease-free and overall survival were 95.5 and 164.6 months, respectively. When compared with MFBC, MCBC showed higher pathologic tumor size (p < 0.001), higher stages (p < 0.001), higher recurrence rates (p = 0.006), and lower DFS (P = 0.009) but with similar OS (P = 0.8). CONCLUSION: Mastectomy is still the primary treatment option for MCBC with higher recurrence rates compared with MFBC. However, BCS for properly selected MFBC is considered oncologically safe, following the same rules of breast conservation for unifocal disease.

Computed tomography independent quantitative determinants of CAD-RADS 4 versus CAD-RADS 3 for calcified coronary lesions.

Purpose: An investigation of coronary computed tomography angiography (CCTA)-derived quantitative parameters to determine CAD-RADS 4 versus CAD-RADS 3 of coronary lesions with moderate to severe calcification. Material and methods: The study included 150 coronary lesions proven to have moderate or severe stenosis by invasive coronary angiography and showing moderate to severe calcification in CCTA. Various CCTA-quantitative parameters were correlated to the degree of stenosis (moderately versus severely stenosed lesions). Their sensitivity and specificity to detect severe stenosis (supposed to be corresponding to CAD-RADS 4) were examined at multiple cut-off points. Results: The calcification remodelling index (CRI) was the only statistically significant independent computed tomo-graphy angiography-derived predictor of severe stenosis versus moderate stenosis on multivariate regression analysis. The best cut-off value was ≤ 0.84, with 77.78% sensitivity and 86.46% specificity. Conclusions: From all quantitative-derived CCTA parameters, CRI ≤ 0.84 was the predictor with the highest diagnostic performance for severe versus moderate stenosis in moderately to severely calcified coronary lesions. Accordingly, CRI can help to determine CAD-RADS 4 versus CAD-RADS 3.

The Effect of Salinized Nano ZrO2 Particles on the Microstructure, Hardness, and Wear Behavior of Acrylic Denture Tooth Nanocomposite.

The wear of acrylic denture teeth is a serious problem that can change the vertical dimensions of dentures. This study evaluates the effect of adding salinized nano ZrO2 particles on the microstructure, hardness, and wear resistance of acrylic denture teeth. Heat polymerizing polymethyl methacrylate resin was mixed with salinized ZrO2 at concentrations of 5 wt.% and 10 wt.%. Acrylic resin specimens without filler addition were used as a control group. SEM/EDS analyses were performed and the Vickers' hardness was evaluated. Two-body wear testing was performed using a chewing simulator with a human enamel antagonist. After subjecting the samples to 37,500 cycles, both height loss and weight loss were used to evaluate the wear behavior. The microstructural investigation of the reinforced-denture teeth indicates sound nanocomposite preparation using the applied regime without porosity or macro defects. The addition of zirconium oxide nanofillers to PMMA at both 5% and 10% increased the microhardness, with values of up to 49.7 HV. The wear mechanism in the acrylic base material without nanoparticle addition was found to be fatigue wear; a high density of microcracks were found. The addition of 5 wt.% ZrO2 improved the wear resistance. Increasing the nanoparticles to 10 wt.% ZrO2 further improved the wear resistance, with no microcracks found.

COVID-19-associated acute invasive fungal sinusitis: Clinical and imaging findings.

BACKGROUND AND PURPOSE: The purpose is to provide a comprehensive report describing the clinical and imaging features of Coronavirus disease 2019 (COVID-19)-related acute invasive fungal sinusitis (AIFS) and associated comorbidities. METHODS: A retrospective study was conducted on 25 patients (12 males and 13 females, mean age of 53.9±9.1 years). All patients had positive polymerase chain reaction test for COVID-19 and histopathological proof of AIFS. Patients underwent computed tomography (CT) and magnetic resonance examinations to assess sinonasal, orbital, and cranial spread. RESULTS: The most prevalent comorbidity among the study cohort was diabetes mellitus (DM). Twenty-one patients (84%) were diagnosed in the post-COVID-19 period after hospital discharge, with a mean interval of 19.1±9.2 days. Steroid treatment was given to 19 patients (76%). Orbital manifestations were the presenting symptoms in all patients, followed by facial edema, nasal discharge, and neurological symptoms. Sinonasal involvement ranged from mucosal thickening to complete sinus opacification by a predominant isodensity on CT, low T1, and high T2 signal intensity with variable enhancement patterns. Twenty-four patients had a unilateral orbital extension, and 12 patients showed signs of intracranial extension. Bone involvement was detected in 16 patients (64%). Follow-up scans in 18 patients (72%) showed rapid progression of the disease. Eight patients (32%) died, six from neurological complications and two from severe respiratory failure. CONCLUSION: Steroids, DM, and severe COVID-19 are the major risk factors of AIFS in the post-COVID-19 era. Imaging scans in all patients revealed different sinonasal, facial, orbital features, and intracranial involvement with rapid progression of the findings on follow-up scans.

Relationship of the pulmonary disease severity scoring with thromboembolic complications in COVID-19.

PURPOSE: To correlate thromboembolic (TE) complications secondary to COVID-19 with the extent of the pulmonary parenchymal disease using CT severity scores and other comorbidities. METHODS: In total, 185 patients with COVID-19 and suspected thromboembolic complications were classified into two groups based on the presence or absence of thromboembolic complications. Thromboembolic complications were categorized based on location. Chest CT severity scoring system was used to assess the pulmonary parenchymal disease severity in all patients. Based into severity scores, patients were categorized into three groups (mild, moderate, and sever disease). RESULTS: The final study cohort consisted of 171 patients (99 male and 72 female) after excluding 14 patients with non-diagnostic CT pulmonary angiography. The TE group included 53 patients with a mean age of 55.1 ± 7.1, while the non-TE group included 118 patients with a mean age of 52.9 ± 10.8. Patients with BMI > 30 kg/m2 or having a history of smoking and HTN were found more frequently in the TE group (p < 0.05). Patients admitted to ICU were significantly higher in the TE group (p < 0.001). There was statistically significant difference (p = 0.002) in chest CT-SS between the TE group (22.8 ± 11.4) and non-TE group (17.6 ± 10.7). The percentage of severe parenchymal disease in the TE group was significantly higher compared to the non-TE group (p < 0.05). Severe parenchymal disease, BMI > 30 kg/m2, smoking, and HTN had a higher and more significant odds ratio for developing TE complications. CONCLUSION: The present data suggest that severe pulmonary parenchymal disease secondary to COVID-19 is associated with a higher incidence of thromboembolic complications.

The role of multidetector computed tomography enterography in the evaluation of localized malignant small intestinal lesions: retrospective radiological and pathological experience.

PURPOSE: Our purpose is to present our experience in using multidetector computed tomography (MDCT) enterography in the evaluation of localized malignant small intestinal lesions with pathological correlation. MATERIAL AND METHODS: We retrospectively evaluated 53 patients of pathologically proven malignant localized small intestinal tumours, who underwent multidetector CT enterography. RESULTS: In this study, the mean age was 51.39 ± 17.4 years. The most commonly affected age group was from 50 to 59 years. The commonest clinical complaint was abdominal pain. The ileum was the most commonly affected anatomical region, showing 25 lesions (47.16%). Radiologically irregular/asymmetric wall thickening was detected in 42 cases(79.24%). Pathologically the most common malignancy was small intestinal adenocarcinoma, followed by carcinoid tumour, lymphoma, and gastrointestinal stromal tumours (GIST). We found that there was a statistically significant association between the pathological lymphadenopathy (p = 0.005) and absent proximal intestinal dilatation (p = 0.01) with intestinal lymphoma. Also, there was a statistically significant association between the extra-intestinal mesenteric fat changes with carcinoid tumours (p = 0.001). Irregular/asymmetric wall thickening was detected in 14 cases of small intestinal adenocarcinoma with a statistically significant association (p = 0.001) while exophytic pathological mass formation was statistically significant associated (p ≤ 0.001) with small intestinal GIST. CONCLUSIONS: Multidetector CT enterography is a non-invasive and accurate method in the evaluation of focal and localized small intestinal malignant lesions. The accurate detection of these lesions depends to some degree on the experience of the radiologist, lesional size, site and pattern of enhancement, as well as adequate intestinal distension.

Mimickers of novel coronavirus disease 2019 (COVID-19) on chest CT: spectrum of CT and clinical features.

COVID-19 (coronavirus disease 2019) is a recently emerged pulmonary infection caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2). It started in Wuhan, China, in December 2019 and led to a highly contagious disease. Since then COVID-19 continues to spread, causing exponential morbidity and mortality and threatening economies worldwide. While the primary diagnostic test for COVID-19 is the reverse transcriptase-polymerase chain reaction (RT-PCR) assay, chest CT has proven to be a diagnostic tool of high sensitivity. A variety of conditions demonstrates CT features that are difficult to differentiate from COVID-19 rendering CT to be of low specificity. Radiologists and physicians should be aware of imaging patterns of these conditions to prevent an erroneous diagnosis that could adversely influence management and patients' outcome. Our purpose is to provide a practical review of the conditions that mimic COVID-19. A brief description of the forementioned clinical conditions with their CT features will be included.

Diffusion tensor imaging parameters in differentiation recurrent breast cancer from post-operative changes in patients with breast-conserving surgery.

AIM OF THE WORK: To investigate mean diffusivity (MD) and fractional anisotropy (FA) measured by diffusion tensor imaging (DTI) as complementary tools to differentiate recurrent breast cancer from post-operative changes in patients with breast-conserving surgery (BCS). PATIENTS AND METHODS: Prospective study was conducted upon 30 patients with BCS that underwent DTI and dynamic contrast MR imaging. DTI was performed using an axial two-dimensional spin-echo echo-planar imaging sequence. The MD and FA of the lesions were calculated by 2 observers. A single pixel seed isotropic region of interest was placed in the solid part of the tumor on the axial color FA map guided by an enhanced part of the tumor. The final diagnosis was done by biopsy for all patients. RESULTS: The pathological examination proved to be recurrent breast cancer (n = 13) and post-operative changes (n = 17). Recurrent breast cancer had significantly lower MD (P = 0.001, 0.001) and higher FA (P = 0.003, 0.02) than in post-operative changes for both observers respectively. At ROC curve analysis of MD, the AUC was 0.86 and 0.85 by both observers. The threshed MD was (0.86, 0.85 × 10-3 mm2/s) used for differentiation between entities revealed sensitivity (76.9%, 92.3%), specificity (82.4%, 64.7%) and accuracy (80%, 76.7%) of both observers respectively. At ROC curve analysis of FA, the AUC was 0.82 and 0.75 by both observers. The threshold FA (0.82, 0.75) was used for differentiation between entities revealed sensitivity (92.3%, 76.9%), specificity (70.6%, 70.6%) and accuracy of (80.0%, 73.3%) of both observers respectively. There was a strong positive correlation of MD (r = 0.86) and FA (r = 0.73) of both observers. Combined analysis of FA and MD used for differentiation between entities had AUC (0.90, 0.88) revealed sensitivity (92.3%, 92.3%), specificity (82.4%, 70.6%) and accuracy of (86.7%, 80.0%) for both observers respectively. CONCLUSIONS: Combined analysis of MD and FA of DTI may play an important role as a non-invasive method for differentiation recurrent breast cancer from post-operative changes in patients with BCS.

The additive role of 1H-magnetic resonance spectroscopic imaging to ensure pathological complete response after neoadjuvant chemotherapy in breast cancer patients.

PURPOSE: To assess the role of 1H-magnetic resonance spectroscopy (1H-MRS) in the confirmation of pathological complete response after neoadjuvant chemotherapy in breast cancer. MATERIAL AND METHODS: Forty-seven cases (53.72 ± 8.53 years) were evaluated using magnetic resonance imaging (MRI) and 1H-MRS with choline (Cho) signal-to-noise ratio (SNR) measured followed by histopathology and ROC analyses. RESULTS: Twelve patients had complete response, and 35 patients had residual disease. Mean age was 53.72 ± 8.53 years. The mean tumour size before neoadjuvant chemotherapy (NAC) was 4.21 ± 0.99 cm and after NAC was 0.9 ± 0.44 cm.Positive total choline signal (tCho) was detected in all cases. The mean Cho SNR before NAC was 9.53 ± 1.7 and after NAC was 2.53 ± 1.3. The Cho SNR cut-off point differentiating between pathologic complete response (pCR) and the non pCR was 1.95. Dynamic MRI showed 83.3% sensitivity, 65.7% specificity, 45.5% positive predictive value, 92.0% negative predictive value, and 70.2% diagnostic accuracy. Combined evaluation done by using the dynamic MRI and 1H-MRS showed 91.5% diagnostic accuracy with 75.0% sensitivity, 97.1% specificity, 75% positive predictive value, and 91.9% negative predictive value. ROC curves of Cho SNR showed statistically significant differences between non pCR and pCR with AUC was 0.955, 82.9% sensitivity, 91.7% specificity, 96.7% positive predictive value, 64.7% negative predictive value, and 85.11% diagnostic accuracy. CONCLUSIONS: 1H-MRS improves the diagnostic accuracy in the prediction of the pCR after NAC.