The effect of acrylamide incorporation on the thermal and physical properties of denture resins

PURPOSE

Polymethyl methacrylate (PMMA) is the most commonly used denture base material despite typically low in strength. The purpose of this study was to improve the physical properties of the PMMA based denture base resins (QC-20, Dentsply Ltd., Addlestone, UK; Stellon, AD International Ltd, Dentsply, Switzerland; Acron MC; GC Lab Technologies Inc., Alsip, Japan) by copolymerization mechanism.

MATERIALS AND METHODS

Control group specimens were prepared according to the manufacturer recommendations. In the copolymer groups; resins were prepared with 5%, 10%, 15% and 20% acrylamide (AAm) (Merck, Hohenbrunn, Germany) content according to the moleculer weight ratio, respectively. Chemical structure was characterized by a Bruker Vertex-70 Fourier transform infrared spectroscopy (FTIR) (Bruker Optics Inc., Ettlingen, Germany). Hardness was determined using an universal hardness tester (Struers Duramin, Struers A/S, Ballerup, Denmark) equipped with a Vickers diamond penetrator. The glass transition temperature (T_g) of control and copolymers were evaluated by Perkin Elmer Diamond DSC (Perkin Elmer, Massachusetts,USA). Statistical analyses were carried out using the statistical package SPSS for Windows, version 15.0 (SPSS, Chicago, IL, USA). The results were tested regarding the normality of distribution with the Shapiro Wilk test. Data were analyzed using ANOVA with post-hoc Tukey test (P<.01).

RESULTS

The copolymer synthesis was confirmed by FTIR spectroscopy. Glass transition temperature of the copolymer groups were higher than the control groups of the resins. The 10%, 15% and 20% copolymer groups of Stellon presented significantly higher than the control group in terms of hardness. 15% and 20% copolymer groups of Acron MC showed significantly higher hardness values when compared to the control group of the resin. Acrylamide addition did not affect the hardness of the QC-20 resin significantly.

CONCLUSION

Within the limitation of this study, it can be concluded that copolymerization of PMMA with AAm increased the hardness value and glass transition temperature of PMMA denture base resins.     

Peel strength of denture liner to PMMA and polyamide: laser versus air-abrasion

PURPOSE

This study investigated the effect of laser parameters and air-abrasion on the peel strength of silicon-based soft denture liner to different denture resins.

MATERIALS AND METHODS

Specimens (N=180) were prepared out of three different denture base resins (Rodex, cross-linked denture base acrylic resin; Paladent, heat-cured acrylic resin; Deflex, Polyamide resin) (75 mm × 25 mm × 3 mm). A silicon-based soft denture liner (Molloplast B) was applied to the denture resins after the following conditioning methods: a) Air-abrasion (50 µm), b) Er,Cr:YSGG laser (Waterlase MD Turbo, Biolase Technology) at 2 W-20 Hz, c) Er,Cr:YSGG laser at 2 W-30 Hz, d) Er,Cr:YSGG laser at 3 W-20 Hz, e) Er,Cr:YSGG laser at 3 W-30 Hz. Non-conditioned group acted as the control group. Peel test was performed in a universal testing machine. Failure modes were evaluated visually. Data were analyzed using two-way ANOVA and Tukey''s test (α=.05).

RESULTS

Denture liner tested showed increased peel strength after laser treatment with different parameters (3.9±0.4 - 5.58±0.6 MPa) compared to the control (3.64±0.5 - 4.58±0.5 MPa) and air-abraded groups (3.1±0.6 - 4.46±0.3 MPa), but the results were not statistically significant except for Paladent, with the pretreatment of Er,Cr:YSGG laser at 3 W-20 Hz. Polyamide resin after air-abrasion showed significantly lower peel strength than those of other groups (3.1±0.6 MPa).

CONCLUSION

Heat-cured acrylic resin, PMMA, may benefit from Er,Cr:YSGG laser treatment at 3 W-20 Hz irradiation. Air-abrasion of polyamide resins should be avoided not to impair their peel bond strengths to silicon-based soft denture liners.     

Long-term Results of Living Donors in Simultaneous Kidney and Liver Transplantations

Introduction

Because of the shortage of organs available for transplantation, living related sequential transplantation with the use of liver and a kidney from the same donor has emerged as a reasonable therapeutic alternative. However, there is insufficient literature about the complications that living donors experience after simultaneous kidney and liver transplantations.

Retroperitoneal Peripheral Nerve Sheath Tumour of Triton Type—A Case Report

The malignant peripheral nerve sheath tumour is the malignant counterpart to benign soft tissue tumours such as neurofibromas and schwannomas. Malignant Triton Tumour is a histological variant of malignant peripheral nerve sheath tumours with rhabdomyosarcomatous differentiation. They are known to develop in cases of neurofibromatosis type 1 (von Recklinghausen’s disease). Malignant peripheral nerve sheath tumor is biologically an aggressive tumour for which the treatment of choice is surgery. Here we report a rare case of malignant peripheral nerve sheath tumour, not associated with neurofibromatosis type 1 and arising in the retroperitoneum.     

Neonatal onset atypical hemolytic uremic syndrome successfully treated with eculizumab

Background

Atypical hemolytic uremic syndrome (aHUS) is characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal impairment. Neonatal cases are extremely uncommon. Plasma therapy is the first choice therapy in patients with aHUS based on the belief of an underlying complement dysregulation. Alternatively, eculizumab, which targets complement 5, is used to block complement activation.

Case-diagnosis/treatment

Sudden onset macroscopic hematuria, hypertension, and bruises over the entire body were noted in a 5 day-old newborn. Investigations revealed hemolytic anemia, thrombocytopenia, renal impairment, and a low serum C3, leading to the diagnosis of aHUS. Fresh frozen plasma (FFP) infusions and peritoneal dialysis for acute kidney injury were initiated. This approach yielded full renal and hematological remission. The patient was discharged with FFP infusions, but subsequently developed three life-threatening disease recurrences at 1, 3, and 6 months of age. The last relapse presented with uncontrolled hypertension and impaired renal function while the patient was receiving FFP infusions. After the first dose of eculizumab, his renal and hematological parameters returned to normal and his blood pressure normalized. Genetic screening of the CFH gene revealed a novel homozygous p. Tyr1177Cys mutation.

Conclusion

Eculizumab can be considered as an alternative to plasma therapy in the treatment of specific patients with aHUS, even in infants.     

Pelvicaliceal anatomical variation between stone bearing and normal contralateral kidneys--does it have an impact on stone formation in pediatric patients with a solitary lower caliceal stone?

PURPOSE: We aimed to investigate the probable effect of pelvicaliceal anatomical differences between stone bearing and normal contralateral kidneys on the etiology of stone formation in children with a solitary lower pole caliceal stone. MATERIALS AND METHODS: We reviewed the clinical records of 25 pediatric patients who underwent SWL for a solitary lower caliceal stone and 15 healthy pediatric patients who served as controls. Lower pole IPA, IL and IW, together with other caliceal variables obtained from the pelvicaliceal anatomy of the stone bearing and contralateral normal kidneys of patients with urolithiasis, and both kidneys of the control group were measured based on excretory urography. Also, total pelvicaliceal volume for both kidneys was calculated. RESULTS: Mean LIPAs of stone bearing kidneys compared to the normal contralateral kidneys was more acute, equal and wider in 52%, 16% and 32% of the patients, respectively. Mean pelvicaliceal volumes of the stone forming and normal kidneys were 1,553.8 mm(3) (range 242 to 7,107) and 581.0 mm(3) (90 to 2,662), respectively, and there was statistical significance only in pelvicaliceal volumes between the stone bearing and contralateral normal kidneys (p <0.001). CONCLUSIONS: Our results reveal that IPA, IL and IW of calices do not have an effect on stone formation in pediatric patients. However, large pelvicaliceal volume seems to be a significant risk factor for stone formation in the lower calix, probably because it creates abnormal urodynamic and morphological features, especially when accompanied by other metabolic abnormalities.     

A New Approach to Tertiary Hyperparathyroidism: Percutaneous Embolization: Two Case Reports

Secondary hyperparathyroidism is one of the most common complications of chronic kidney failure. If prolonged, parathyroid hormone release gains autonomy and tertiary hyperparathyroidism with parathyroid adenoma or hyperplasia can be develop. Tertiary hyperparathyroidism is associated with increased risk of mortality and morbidity; thus, treatment is recommended. Medical treatment includes phosphate binders, vitamin D analogues, and calcimimetic agents. Most cases of tertiary hyperparathyroidism can be controlled with medical treatment. When medical treatment options prove insufficient, parathyroidectomy is recommended. However, recurrence after parathyroidectomy is possible, which requires an alternative treatment. We present our percutaneous embolization experience, which has not been tried in the treatment of tertiary hyperparathyroidism in renal transplantation patients diagnosed with tertiary hyperparathyroidism.     

Use of shear wave elastography to differentiate benign and malignant breast lesions

PURPOSE

We aimed to determine the correlations between the elasticity values of solid breast masses and histopathological findings to define cutoff elasticity values differentiating malignant from benign lesions.

MATERIALS and METHODS

A total of 115 solid breast lesions of 109 consecutive patients were evaluated prospectively using shear wave elastography (SWE). Two orthogonal elastographic images of each lesion were obtained. Minimum, mean, and maximum elasticity values were calculated in regions of interest placed over the stiffest areas on the two images; we also calculated mass/fat elasticity ratios. Correlation of elastographic measurements with histopathological results were studied.

RESULTS

Eighty-three benign and thirty-two malignant lesions were histopathologically diagnosed. The minimum, mean, and maximum elasticity values, and the mass/fat elasticity ratios of malignant lesions, were significantly higher than those of benign lesions. The cutoff value was 45.7 kPa for mean elasticity (sensitivity, 96%; specificity, 95%), 54.3 kPa for maximum elasticity (sensitivity, 95%; specificity, 94%), 37.1 kPa for minimum elasticity (sensitivity, 96%; specificity, 95%), and 4.6 for the mass/fat elasticity ratio (sensitivity, 97%; specificity, 95%).

CONCLUSION

SWE yields additional valuable quantitative data to ultrasonographic examination on solid breast lesions. SWE may serve as a complementary tool for diagnosis of breast lesions. Long-term clinical studies are required to accurately select lesions requiring biopsy.Breast cancer is associated with high morbidity; ∼1.38 million new cases and 458 000 deaths occur annually worldwide (1). Breast cancer is by far the most common cancer in females of both developed and developing countries, and remains a major public health problem.Annual mammographic screening is valuable for early detection of breast cancer, reducing mortality and morbidity, particularly of patients with tumors in fatty breast tissue (2). Increase in breast tissue density over time is a serious problem; this reduces the diagnostic accuracy of breast cancer, especially in younger females (3). Thus, as the proportion of glandular breast tissue rises, other imaging methods are required (4).Gray-scale ultrasonography is a valuable adjunct to mammography and other breast imaging methods, affording highly sensitive assessment of breast masses and differentiating benign solid breast lesions from those that are malignant (5–7). However, ultrasonography is strongly subjective and poorly specific (8–10).Breast biopsy remains the gold standard for definitive diagnosis of suspicious breast lesions. Although the total number of females referred for interventional diagnostic procedures represents a small percentage of any screened population, the healthcare resources consumed by such females are disproportionately high (11). Further, the pathological result is benign in up to 75% of all cases (11–13). Therefore, a reliable, noninvasive, costeffective method helping to differentiate benign from malignant breast lesions, thus reducing the number of unnecessary interventional diagnostic procedures, would be valuable.Sonoelastography uses ultrasound to assess tissue stiffness (elasticity), which can be described using Young’s modulus: E=σ/ε, where σ is the applied stress and ε the resultant tissue deformation. Two principal sonoelastographic approaches are available; these are static (strain) and transient (vibration; shear wave) elastography. In static elastography, a transducer is used to compress tissue and the resulting strain is presented as a color map of tissue elasticity superimposed on the real-time gray-scale sonogram.Static elastography is associated with significant interobserver variability, and uses elastographic scoring (ES) or strain ratio (SR) measurement as a diagnostic parameter. Both ES and SR are subjective semi-quantitative measures (14, 15). Shear wave elastography (SWE) is a novel technique applicable to soft tissue. In SWE, transverse shear waves spreading laterally from the tissue are tracked, and the speed of propagation calculated. SWE yields real-time quantitative data and is highly reproducible compared to static elastography (16, 17). Reproducibility of the latter technique is considered to be a major problem and may compromise patient outcomes. Thus, further work on the utility of SWE is needed.In the present study we sought to correlate the SWE values of a series of solid breast masses with histopathological findings, and to determine cutoff elasticity values allowing benign and malignant tumors to be distinguished.