HARDNESS AND ELASTIC MODULUS ASSESSMENT FOR TWO ALIGNER MATERIALS BEFORE AND AFTER THERMOCYCLING: A COMPARATIVE STUDY.

Orthodontic clear aligners as an alternative to traditional braces have become increasingly ubiquitous in the last few years. Therefore, understanding the properties of the aligner materials can help to produce more accurate results of the treatment and provide more data for orthodontists who are currently using or intend to use this technology. This study aimed to investigate the effect of thermocycling on some mechanical properties (Hardness and Elastic Modulus) of two thermoplastic products used in the fabrication of orthodontic aligners. Two thermoplastic products of Duran® 0.75 mm and Erkodur® 1 mm were used in this study. A specially prepared disk fabricated from risen material with dimensions of (15mm) in diameter and (6mm) in thickness which was fabricated with a 3D printer was used for hardness assessment. Twenty sheets were thermoformed over the round disk for each product. Whereas, for elastic modulus, a Dog bone specimen with dimensions 8 mm in width and 150 mm in length was made from resin by using a 3D printer. The shore D hardness test was used to measure the hardness of the two products before and after thermocycling. For elastic modulus, thermoplastic sheets that were less than 1mm in thickness were measured according to the ASTMD 882-02 and those with 1mm were measured according to the ASTMD 638-02a. The elastic modulus was measured using a tensile test by a universal testing machine before and after thermocycling. Erkodur model® was higher than Duran® in the hardness test before and after thermocycling. But, Erkodur model® showed significant, however, Duran® showed no significant change in hardness before and after thermocycling. The elastic modulus test for the two materials showed a significant difference between Duran® and Erkodur® models. The elastic modulus of Duran® was higher than Erkodur® before and after thermocycling. The hardness of the Erkodur® product was higher than that of Duran®, whereas the elastic modulus of the Duran® product was higher than Erkodur® before and after thermocycling. On the other hand, thermocycling reduces the hardness of the Erkodur® product more than that of Duran® and did not affect the elastic modulus of each product.

Split-bolus single-pass CT for vascular complications in acute pancreatitis: assessment of radiation dose and multi-phasic contrast enhancement compared to single-bolus multi-pass CT.

AIM: To assess vascular contrast enhancement and radiation dose of split-bolus single-pass computed tomography (CT) compared to single-bolus multi-pass CT for acquiring a multi-phasic study. MATERIALS AND METHODS: Patients who underwent CT for acute pancreatitis were included retrospectively. Thirty consecutive patients scanned with a split-bolus protocol were compared to 30 consecutive patients scanned with a single-bolus protocol. Data were collected on attenuation measurements (aorta, portal vein and spleen) and images were assessed for subjective vascular enhancement quality and splenic homogeneity. Radiation dose was measured by dose-length product (DLP). RESULTS: There was no significant difference in the aortic (p = 0.88) or portal vein (p = 0.35) attenuation values between the two groups. The percentage of examinations reaching the target aortic and portal attenuation in the split-bolus group were 96.7% and 93.3%, and in the single-bolus group were 96.7% and 85.7%, respectively. The mean DLP was 492 mGy.cm for the single-bolus group and 940 mGy.cm for the split-bolus group (p < 0.0001). Subjective assessment revealed higher rates of splenic heterogeneity in the split-bolus group. DISCUSSION: In acute pancreatitis, split-bolus imaging can produce arterial and venous enhancement comparable to a multi-pass technique with a significant reduction in radiation dose. Loss of temporal resolution and increased splenic heterogeneity are the main disadvantages. The low prevalence of pseudoaneurysms favours the lower-dose imaging technique.

Tooth size and dental arch dimensions: a stereophotogrammetric study in Southeast Asian Malays.

OBJECTIVE: To investigate tooth size and dental arch dimensions in Malays using a stereophotogrammetric system. SETTING AND SAMPLE POPULATION: The sample consisted of 252 subjects with ages ranged from 13 to 30 years. MATERIALS AND METHODS: Images of dental casts were captured by stereophotogrammetry and selected variables were measured using a three-dimensional (3D) imaging system. Sex differences and changes associated with age were assessed, and interrelationships between different variables were explored within the study group. RESULTS: Men had significantly larger mesio-distal crown widths and dental arch dimensions than women (p < 0.05). None of the dental arch dimensions or mesio-distal crown widths showed a significant change because of age except the widths of the upper canine, lower first molar and central incisor. Significant correlations of tooth size with dental arch dimensions were found, particularly with arch lengths and perimeters. A principal component analysis showed interrelationships between the majority of tooth size variables with inter-canine width, arch length and perimeter distances. CONCLUSION: This study has established new reference data for tooth size and arch dimensions in Malays and demonstrated patterns of variation that are relevant to anthropologists interested in making comparisons within and between different populations and also to clinicians developing treatment plans for their patients. The study confirmed the accuracy of the 3D photogrammetric method for measuring dental casts.

E-cadherin and Snail Immunoexpression in Colorectal Adenocarcinomas.

Epithelial-mesenchymal transition (EMT) is a fundamental process which governs invasiveness. E-cadherin plays a major role in development, organogenesis and tissue formation, but also in tumor progression. Snail is a transcription factor described as a direct repressor of E-cadherin during development and in carcinogenesis. In this study we analyzed E-cadherin and Snail immunoexpression in 47 cases of colorectal adenocarcinoma (CRC) in comparison with some histopathological prognostic factors. The majority of cases were G2 tumors in stages II and III, with vascular and perineural invasion. All cases showed positive cytoplasmic signal for E-cadherin and Snail. E-cadherin reactions were intense with the highest composite score (CS) values in CRC G1. CS values of E-cadherin decreased with the advancement in tumor stage and the association with vascular and perineural invasion was statistically significant. Snail immunoreaction was intense with the highest values of CS in CRC G3, being more evident with the increase of tumor staging, aspect which was statistically significant. CS and Snail association demonstrated a statistically significant aspect related to vascular invasion. We found a negative linear correlation of E-cadherin and Snail expression. The obtained results indicate the implication of Snail and E-cadherin in EMT of CRC, aspect which is useful in the evaluation and stratification of patients with CRC for the targeted specific therapy.

Importance of Follow-Up and Early Detailed Evaluation in Early Onset Growth Restricted Fetuses.

Early onset fetal growth restriction (EO-FGR) is associated with significant feto-maternal complications, therefore efforts should be made to identify the causes and the potential outcome of the pregnancy. Some of the pitfalls in first-trimester imaging of the fetal anomalies are related to the inadequacy of the examination, because of the fetal position and limited clarity in relation to the size of the structures being examined. In this paper we present a case where careful ultrasound scan follow-up and the use of both approaches transabdominal and transvaginal were useful to complete a detailed structural evaluation as part of the diagnosis, management and prognosis of a fetuses diagnosed with EO-FGR in the first trimester and a triploidy with atypical ultrasound features.

Histopathological Prognostic Factors for Colic Adenocarcinoma.

The majority of colorectal carcinomas are adenocarcinomas derived from the colic mucosae cell, more frequently moderately differentiated. The purpose of this study was to determine de incidence of CRC and the relationship between histopathological risk factors in patients with colic adenocarcinomas. The study included 144 cases of CRC diagnosed within the Pathology Laboratory of the Clinical County Hospital of Craiova in the year 2017.The biological material consisted in samples from colectomies and hemicolectomies provided from patients admitted within the surgical clinics of the same hospital, then fixed with 10% buffered formalin and afterwards processed using the classic histopathological technique of paraffin inclusion and staining with hematoxylin and eosin. We observed certain histopathological parameters such as: pattern, grading, stage, vascular invasion and neural invasion. The mean age of diagnostic was 68.6 ± 11.2, and it was predominantly male patients (64.6%). Most cases presented with mucinous pattern (31.9%) and cribriform comedocarcinoma type (29.9%). The majority were classified as stage III B (34%), being moderately differentiated (64.6%) and associated with vascular invasion (47.2%) and perineural invasion (25.7%). Statistical analysis indicated significant relationships between tumor stage and differentiation grade (p<0.01, χ²test), as well as between tumor stage and vascular invasion (p<0.05, χ²test), without including perineural invasion (p<0.05, χ²test).

Histopathological Prognostic Factors in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (CCRCC) are the most frequent type of renal cell carcinoma. Fuhrman grade and tumor stage are prognostic factors with great importance in survival rate. This study was performed on 75 cases of CCRCC diagnosed by the Anatomical Pathology Laboratory of the County Clinical Emergency Hospital of Craiova between 2014 and 2017. The biological material was represented by pieces of nephrectomy. The cases were analyzed on two criteria: epidemiology (age, sex) and histopathology (Fuhrman grade, tumor stage, architectural pattern, sarcomatoid transformation, and necrosis). Statistical analysis was done using Chi Square tests in IBM SPSS software. Average diagnosis age of CCRCC was 58.8±10.2 years, predominantly in male patients (66.7%). Tumor sizes were between 2 and 14cm, with an average of 6.7±2.9cm. Most cases were determined to be tumor stage III (60%) and Fuhrman grade 2 (56%), followed, in order of frequency, by tumor stages I and II (28% and 10.7%) and Fuhrman grades 3 and 1 (21.3% and 20%). High Fuhrman grade CCRCC were significantly associated with advanced tumor stage (p<0.05, χ2 test). Most cases presented a mixed pattern, significantly associated with advanced tumor stages (p<0.05, χ2 test). Even though the presence of sarcomatoid transformation was more frequent in advanced tumor stages, it wasn't significantly linked to them (p<0.05, χ2 test). Conclusions: Analyzed histopathological parameters are useful for determining CCRCC aggressiveness. CCRCC in advanced tumor stages is associated with high Fuhrman grade and mixed architectural pattern.

[Work injuries in building construction, metal shaping, and food production sectors in Jericho District in the Palestinian territory].

Work injuries and accidents have a considerable impact on public and community health. This study targeted three work sectors: metal shaping, food production and building construction. Work injuries that occurred in these sectors were compared for the years 1999 and 2000 in Jericho District in the West Bank of Palestine. One hundred three injuries were examined and information recorded about the nature of the injury, site of injury in the body, direct cause of injury and some personal information about the injured worker. The most vulnerable group were young people in their twenties, and mostly those working in the metal shaping and building construction sectors. The kinds and sites of injuries varied. The data were compared with data from 1997, 1998 and 2001-2003, although only loosley as the available data about work injuries for these years were limited and inaccurate.

Solvent exposures at shoe factories and workshops in Hebron City, West Bank.

Exposure to organic solvents has been reported to increase the risks for acute and chronic health effects among shoe industry workers. In developing countries, protection against chemical exposures is often not provided. The study was conducted to identify working conditions and estimate the concentrations of organic solvents used in shoe factories and workshops in Hebron City. Personal interviews containing questions related to personal protective equipment (PPE) were used to identify working conditions, and samples collected from factories and workshops were analyzed using gas chromatography. Geometric means (GMs) were calculated for the solvents. Six major organic solvents were detected in the factories. Acetone (GM = 51.5 mg/m3, GSD = 3.82) was common in gluing tasks. Dichloromethane (GM = 47 mg/m3, GSD = 2.62) was common in cleaning tasks. Heptane, methylethyl ketone, n-hexane, and toluene were common in gluing tasks. Four major organic solvents were detected in the workshops: acetone (GM = 32.3 mg/m:3, GSD = 6.33), toluene (GM = 70.3 mg/m3, GSD = 3.06), n-hexane (GM = 19.4 mg/m3:, GSD = 2.65), and methylethyl ketone (GM = 130 mg/mM3, GSD = 1.5). 81% of the factory workers had never used respiratory protective equipment, and 92% had never used work clothes. 97% of the workers in the workshops had never used respiratory protective equipment, 94% had never worn gloves, and 90% had never used work clothes. Exposures to solvents in the absence of personal Protective equipment, tasks barriers, and mechanical ventilation can adversely affect health.

Prevalence of self-reported health complaints among shoe workers of small workshop exposed to organic solvents in Hebron City, West Bank: a cross-sectional survey.

The study was conducted to estimate the prevalences of neurological disorders and mucous membrane irritation complaints among workers of shoe workshops in Hebron City, in particular to measure the associations between the occurrence of symptoms indicating polyneuropathy among workers and exposure to organic solvents in the glueing tasks. A group of 103 male workers from 30 workshops, exposed to organic solvents for more than one year were recruited to the study during the years 1996-1997. A validated Swedish neuropsychiatric questionnaire which contained questions on neurological and mucous irritation symptoms was used. Prevalence ratios were used as an indicator for relative risk. The overall prevalence of painful tingling of limbs (used as indicator of polyneuropathy) was high among the workshop workers (40%) and was significantly associated with long term exposure to organic solvents in glueing tasks (PR 2.8: 95% CI 1.0-8.3). Moderate associations were seen in other tasks. Headache and mental irritability did not show any association with organic solvent exposure in the workshop tasks. Breathing difficulty showed a moderate non-significant association with long term exposure to organic solvents (72 months) in cleaning tasks (1.9,0.7-4.8), while sore eyes also showed a moderate non-significant association with exposure to organic solvents for 25-72 months in the glueing tasks. Long term exposure to n-hexane (mainly found in the glues) could be the main cause of polyneuropathy among the workers of Hebron shoe workshops. The absence of effective ventilation systems and personal protective equipment might increase the prevalence of polyneuropathy among these workers. In conclusion, glues containing high concentrations of n-hexane are still in use in many shoe workshops in Hebron City (as well as in other developing countries), and long term exposure to n-hexane in glueing compounds could result in polyneuropathy among the workers. However, in the absence of objective measurements our results must be interpreted with caution. Well planned longitudinal studies with objective measures of exposure and disease are important for future research in developing countries.

[The delayed split-skin coverage--use and advantages]. / Die verzögerte Spalthautdeckung--Anwendung und Vorteile.

In 119 patients a "delayed skin flap transplantation" was carried out after excision of malignant melanomas. The skin graft can be stored in a refrigerator at 4 degrees C up to two weeks without damage to the transplant. The transplantation may be accomplished at any time, but is usually due 3 to 4 days postoperatively. Advantages of this method are decreased risk of local infection, early mobilisation of the patient and generally good cosmetic results.

Prevalence of neuropsychiatric and mucous membrane irritation complaints among Palestinian shoe factory workers exposed to organic solvents and plastic compounds.

BACKGROUND: Long-term exposure to organic solvents is associated with neuropsychiatric and mucus membrane irritation. In developing countries, efforts to secure a good working environment are inadequate and protection against chemical exposures is often neglected. METHODS: In a cross-sectional survey, the prevalence of self-reported health complaints and the association with long-term exposure to solvents and plastic materials in the work environment was studied among 167 shoe-factory workers. Prevalences and adjusted prevalence ratios (PR)were calculated in Cox regression. 95% confidence intervals were estimated for PRs of adverse health effects. RESULTS: Overall, the workers reported high prevalences of neuropsychiatric and mucus membrane complaints: headache (65%), mental irritability (53%), tingling of limbs (46%), and sore eyes (43%). Cleaning work was associated with tingling of limbs (PR = 1.8, 1.0-3.2), sore eyes (PR = 1.9, 1.1-3.3), and breathing difficulty (PR = 2.0, 1.0-3.9); plastic work was associated with tingling of limbs (PR = 1.8, 1.2-2.9)and sore eyes (PR = 1.7, 1.1-2.7); and varnishing was associated with breathing difficulty (PR = 1.9, 1.1-3.5). CONCLUSIONS: The high prevalence of self-reported health complaints and the exposure-outcome association could be due to volatile organic solvents (dichloromethane, n-hexane)and plastic compounds (isocyanates and polyvinyl chloride). Absence of a satisfactory work environment is likely to contribute to high exposure levels.

[Work injuries in building construction, metal shaping, and food production sectors in Jericho District in the Palestinian Territory]

Work injuries and accidents have a considerable impact on public and community health. This study targeted three work sectors: metal shaping, food production and building construction. Work injuries that occurred in these sectors were compared for the years 1999 and 2000 in Jericho District in the West Bank of Palestine. One hundred three injuries were examined and information recorded about the nature of the injury, site of injury in the body, direct cause of injury and some personal information about the injured worker. The most vulnerable group were young people in their twenties, and mostly those working in the metal shaping and building construction sectors. The kinds and sites of injuries varied. The data were compared with data from 1997, 1998 and 2001-2003, although only loosley as the available data about work injuries for these years were limited and inaccurate