Lightweight Geopolymer Made of Pumice with Various Aluminum Powder Ratios

In this work, a lightweight geopolymer was prepared using various mass proportions of extra fine aluminum powder and pumice stone that is durable to heat and sound-proof. The effect of NaOH concentration, aluminum mass ratio, the curing temperature and the curing time of the mixture on the compressive strength of the lightweight geopolymers were examined. The concentration of NaOH was found to be 2 M while the mass proportion of Na₂SiO₃/NaOH was found to be 17.5 on the lightweight geopolymers that have the highest compressive strength and the best workability in experiments. The lightweight geopolymer attained the best compressive strength with 1.6 MPa on the 28th day of curing process at 40°C. The mass proportion of aluminum used in the lightweight geopolymer was 2.5% as the density of the lightweight geopolymer obtained was 0.9 g/cm³. Their properties were examined using the Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy

MODELLING OF DRUG RELEASE KINETICS FROM SPHERICAL PEGDA HYDROGELS

Hydrogels are attractive controlled delivery systems of drugs due to higher surface to volume ratio compared to macroscopic systems. In the scope of the presented work, PEG-DA based spherical hydrogels were synthesized, characterized, and. in vitro controlled release kinetics of the drug from microspheres for different PEG-DA and photoinitiator ratios were investigated with various mathematical models. In the first part of the work, synthesis of PEG-DA based spherical hydrogels by free-radical photopolymerization method by using photoinitiator was done. Polyethylene glycol diacrylate (PEG-DA) was used as macromer, ethylene glycol dimetacrylate (EGDMA) and 2,2 dimetoxy-2 phenylacetophenon (DMPA) were used as cross-linking agent and photoinitiator, respectively. In order to observe the effects of the amounts of the compounds, the ratios of the macromers was tested at 30 and 50 % by weight and photoinitiator ratio was arranged as 0.5 and 1 % by weight while cross-linker ratio was kept constant as 1 % by weight. The chemical characterizations of hydrogel were performed with ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy) spectrums of hydrogels synthesized in the disc form with the same compositions and the characteristic pikes of PEG-DA was observed. Optic microscope images of synthesized, microspheres were taken. Then drug release experiments of polymer spherical hydrogels with known weight and gentamicin amount, were performed in pH 7 and pH 2 buffer solutions with certain ionic strengths. The drug release kinetic models, zero order, first order, second order, Hixson-Crowell, Weibull, Higuchi, Baker-Lonsdale, and Korsmeyer-Peppas mathematical models were selected. The data were arranged for each hydrogel group according to mathematical models from the graphical change of drug delivery results obtained with time. The mathematical models with highest regression coefficients, in other words the most suitable models for in vitro controlled drug release from PEGDA microspheres were predicted using MATLAB program

Does preventive single dose of intravenous dexketoprofen reduce pain and swelling after orthognathic surgery? A prospective, randomized, double blind clinical trial

BACKGROUND: The purpose of this study was to evaluate the effect of a single-dose intravenous dexketoprofen administration for preventive analgesia on postoperative pain and reducing swelling in double jaw surgery. MATERIAL AND METHODS: The authors designed a prospective, randomized, and double-blind cohort study. Patients who have Class III malocclusion were randomly divided in two groups. 50 mg intravenous dexketoprofen trometamol were administrated 30 minutes before incision in treatment group, while intravenous sterile saline was administrated 30 minutes before incision in placebo group. The primary predictor variable was treatment group. Primary outcomes were pain, swelling and 24-hour opioid intake. Patient- controlled analgesia with tramadol was given for management of postoperative pain. Other variables were demographic and operation related parameters. Visual analogue scale was used to evaluate postoperative pain. 3dMD Face System (3dMD, USA) was used to measure postoperative swelling. Data were analysed using two independent samples t test and Mann Whitney U test. RESULTS: The study sample was composed of 30 patients with a mean age of 20,63 years and 21 were female. Preemptive dexketoprofen administration decreased postoperative tramadol consumption by 25.9% compared to placebo group, and there was a statistically significant decrease in VAS scores (p0,05). CONCLUSIONS: Preventive administration of intravenous dexketoprofen provides adequate analgesic effect in the postoperative 24-hour period and reduces opioid consumption in orthognathic surgery

Comparison of the Analgesic Effects of Pulse Radiofrequency and Cryoablation in Rabbits with Mental Nerve Neuropathic Pain

Purpose: After mental nerve injury, several sensory disorders may occur. The alterations in sensation may differ from mild paresthesia to complete anesthesia, or neuropathic pain. Neuropathic pain is a difficult clinical condition to manage. The aim of this study was to compare the analgesic effects of pulsed radiofrequency (PRF) and cryoablation in an experimental mental nerve neuropathic pain model in rabbits. Materials and Methods: Fifteen rabbits were divided into three groups. One‑third to one‑half of the mental nerve was ligated with 4‑0 silk sutures. In Group 1, a nonconducting PRF electrode was placed on the mental nerve for 6 min, whereas the mental nerve was exposed to PRF in Group 2. In Group 3, the cryoablation was processed. The responses to thermal and mechanical stimuli were measured at the 1st, 2nd, 3rd, and 4th weeks. Results: There were no statistically significant differences among the groups for thermal withdrawal latency to heat stimulation in any weeks (P > 0.05). However, a significant difference was found between the groups (P < 0.05) in the 3rd and 4th weeks for mechanical withdrawal latency values. Conclusions: Both PRF and cryoablation therapies are successful in the treatment of experimentally induced mental nerve neuropathic pain in rabbits.Keywords: Cryoablation, mental nerve, neuropathic pain, pulse radiofrequenc

Evaluation of aggrecan and adipokine levels in temporomandibular joint synovial fluid

© 2021The aim of this study was to investigate the effect various mediators in synovial fluid (SF) on the pathogenesis of temporomandibular disorders (TMD) and to evaluate the relationship between clinical and radiological features of temporomandibular joint (TMJ) diseases. Patients who had received SF sample during arthrocentesis because of TMD were included in this study. Clinical and radiological records were evaluated retrospectively. Enzyme-Linked ImmunoSorbent Assay (ELISA) method was used for analysis of aggrecan, adiponectin, resistin, apelin, Vascular Endothelial Growth Factor (VEGF) and Prostaglandin E2 (PGE2) in SFs. 59 joints of 41 patients were included in the study. Anterior disc displacement with reduction (ADDwR) was detected in 22 joints, anterior disc displacement without reduction (ADDwoR) was detected in 29 joints and osteoarthritis (OA) in 8. In OA group, PGE2 level was significantly higher than the other groups (p = 0.029). Aggrecan and PGE2 levels were statistically higher in joints with localized pain (p = 0.030, p = 0.029). The aggrecan level was statistically significant higher in patients who had degenerative changes in radiological examinations (p = 0.044). Resistin was correlated with PGE2 and aggrecan (p = 0.011), and apelin showed positive correlation with VEGF (p˂0.001). The detection of aggrecan and adipokines in SF may be a precursor of degenerative joint disease and it should be taken into account that the presence of localized pain in the joint area may be an early sign of degenerative changes

Risk Factors Influencing Recovery of Neurosensory Disturbances Following Sagittal Split Ramus Osteotomy.

Purpose: The aim of this study is to determine the risk factors influencing the recovery time of neurosensory disturbances (NSD) following sagittal split ramus osteotomy

The Role of the Urine Dipstick Test in the Detection of Abnormal Proteinuria Using Different Cut-off Levels in Hypertensive Pregnancies Hipertansif Gebeliklerde Farklı Kesim Değerleri Kullanılarak Anormal Proteinüri Saptanmasında Spot İdrar Protein Ölçümünün Rolü

© 2022, Duzce University Medical School. All rights reserved.Aim: The aim of this study was to determine the diagnostic accuracy of different urine dipstick protein threshold levels in predicting the presence of abnormal proteinuria in pregnant women with hypertension. Material and Methods: A total of 326 singleton pregnant women who underwent 501 urine protein tests and who had suspected preeclampsia were included in this retrospective study. Patient data was taken including medical and obstetric history. The results of dipstick urinalysis and concurrent 24-hour urine protein excretion measurements were compared to determine the accuracy of urinalysis. Results: A dipstick result of 1+ was found to be the best cut-off to predict 500 mg of protein excretion per day, with sensitivity and specificity of 62.09% and 88.97%, respectively. A 2+ proteinuria dipstick cut-off had high specificity and positive predictive value (PPV) (99.05% and 98.84%, respectively) for the prediction of 300 mg of protein excretion per day; this cut-off had low sensitivity (21.46%). A cut-off of 1+ also provided satisfactory specificity and PPV (91.43% and 94.48%, respectively) for the detection of 300 mg of protein excretion per day, but sensitivity was compromised (38.89%). Among 301 patients with negative dipstick results, 212 had a 24-hour urine protein extraction greater than 300 mg, with a false negative rate of 70.43%. Conclusion: The results suggest that the urine protein dipstick measurement has limited quantitative ability for the prediction of abnormal proteinuria. Additionally, the use of 500 mg 24-hours protein excretion as a cut-off value for abnormal proteinuria may provide useful data

Effects of boric acid on bone formation after maxillary sinus floor augmentation in rabbits.

PurposeAugmentation of the maxillary sinus floor with bone grafting is commonly used for successful treatment of edentulous posterior maxilla with dental implants, and it is essential to maintain good bone volume and quality for long-term success of dental implants. The aim of this experimental study was to investigate the local and systemic effects of boric acid on new bone formation after maxillary sinus floor augmentation (MSFA).Materials and methodsTwenty-four male, New Zealand rabbits were randomly divided into three groups with eight rabbits each, and bilateral MSFA was performed in each animal. An autogenous bone/xenograft mixture was used to augment the maxillary sinuses in each group. Group 1 was determined as control with no additional materials, whereas 3mg/kg boric acid (BA) was added to the mixture in group 2, and 3mg/kg boric acid solution added to drinking water daily in group 3.ResultsThe animals were sacrificed and also histologic, histomorphometric, and immunnohistochemical analyses were performed at weeks 4 and 8. At week 4, bone regeneration was better in the local BA group than in the control and systemic BA groups (p0.05).ConclusionSignificant higher new bone formation was revealed by BA at early healing especially with local application. BA may be a therapeutic option for improving the bone regeneration