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1.
Push-out bond strength of calcium-silicate cements following Er:YAG and diode laser irradiation of root dentin.
Mohammadian, F, Soufi, S, Dibaji, F, Sarraf, P, Chiniforush, N, Kharrazifard, MJ
Lasers in medical science. 2019;(1):201-207
Abstract
This study aimed to compare the effects of diode and Er:YAG laser irradiation of root dentin on push-out bond strength of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cements. An in vitro experimental study was conducted on 90 dentin discs, cut out of freshly extracted human teeth. The discs were instrumented to obtain 1.3-mm lumen diameter. Then, they were randomly divided into six groups (n = 15). Groups 1 and 4 subjected to diode laser (Wiser, Doctor Smile, Italy) (980 nm, 1 W, continuous mode) for 10 s and filled with MTA and CEM cements. Groups 2 and 5 subjected to Er:YAG laser (Deka, Italy) (2940 nm, 1 W, 10 Hz, 230 μs) for 10 s and filled with MTA and CEM cements. Groups 3 and 6 (control groups) were filled with MTA and CEM cements without laser irradiation. After 7 days, push-out bond strength test was performed using a universal testing machine in order to evaluate the adhesion of the biomaterials to dentin. The samples were evaluated under a light microscope at × 40 magnification to determine the mode of fracture. Data were analyzed using two-way ANOVA. The highest push-out bond strength (8.76 ± 3.62 MPa) was noted in group 1 (diode/MTA), which was significantly higher than the other groups (P < 0.001). The lowest bond strength (2.61 ± 0.81) was noted in group 6 (control/CEM). Diode laser significantly increased the bond strength of both cements (P < 0.05), but Er:YAG laser irradiation only increased the bond strength of CEM and had no significant effect on MTA (P = 0.603). The bond strength of MTA control group was higher than that of CEM control group (P = 0.001). Push-out bond strength of endodontic cements can be affected by dentin conditioning with diode 980 nm and Er:YAG laser. Nine hundred eighty-nanometer diode laser irradiation is recommended to increase the bond strength of endodontic cements particularly the CEM cement to dentin.
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2.
Does Adding Various Accelerators to Mineral Trioxide Aggregate Have a Negatively Effect on Push-Out Bond Strength?
İlker, A, Sarıyılmaz, E, Çakici, F
Medical principles and practice : international journal of the Kuwait University, Health Science Centre. 2019;(1):36-40
Abstract
OBJECTIVE This study compares the effect of the white mineral trioxide aggregate (WMTA) accelerators, including disodium hydrogen orthophosphate (Na2HPO4; 2.5 wt%), calcium chloride (CaCl2; 5 and 10 wt%), and KY jelly, on the push-out bond strength of WMTA. The null hypothesis was that the WMTA accelerators would not affect the push-out bond strength of WMTA. MATERIALS AND METHODS Slices (2-mm-thick) were obtained from 75 human mandibular molar distal roots. The slices were enlarged up to size 6 Gates-Glidden burs to obtain a 1.5-mm canal diameter. The slices were randomly divided into 4 experimental groups and a control group (n = 15 in each group). Freshly prepared WMTA mixture was placed into the root slices and stored at 37°C in a 100% humidified atmosphere for 60 days. The force required to dislodge the WMTA cement from the root slice was determined using a universal testing machine. The push-out bond strength was calculated. RESULTS Push- out bond strength of 5- and 10-wt% CaCl2, and 2.5-wt% Na2HPO4 WMTA groups was significantly lower than in the KY-jelly and control groups (p < 0.05). The mean push-out bond strength of KY jelly was lower than in the control group but not statistically significant. CONCLUSION The addition of KY jelly to WMTA did not have an adverse effect on the push-out bond strength of WMTA, in contrast to the other accelerators, including Na2HPO4 and CaCl2, which reduced the push-out bond strength.
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3.
Comparison between calcium hydroxide mixtures and mineral trioxide aggregate in primary teeth pulpotomy: a randomized controlled trial.
Silva, LLCE, Cosme-Silva, L, Sakai, VT, Lopes, CS, Silveira, APPD, Moretti Neto, RT, Gomes-Filho, JE, Oliveira, TM, Moretti, ABDS
Journal of applied oral science : revista FOB. 2019;:e20180030
Abstract
OBJECTIVES To evaluate the effect of calcium hydroxide (CH) associated with two different vehicles as a capping material for pulp tissue in primary molars, compared with mineral trioxide aggregate (MTA). METHODOLOGY Forty-five primary mandibular molars with dental caries were treated by conventional pulpotomy using one of the following materials: MTA only (MTA group), CH with saline (CH+saline group) and CH with polyethylene glycol (CH+PEG group) (15 teeth/group). Clinical and periapical radiographic examinations of the pulpotomized teeth were performed 3, 6, and 12 months after treatment. Data were tested by chi-squared analysis and a multiple comparison post-test. RESULTS The MTA group showed both clinical and radiographic treatment success in 14/14 teeth (100%), at all follow-up appointments. By clinical evaluation, no teeth in the CH+saline and CH+PEG groups had signs of mobility, fistula, swelling or inflammation of the surrounding gingival tissue. However, in the CH+saline group, radiographic analysis detected internal resorption in up to 9/15 teeth (67%), and inter-radicular bone resorption and furcation radiolucency in up to 5/15 teeth (36%), from 3 to 12 months of follow-up. In the CH+PEG group, 2/11 teeth (18%) had internal resorption and 1/11 teeth (9%) presented bone resorption and furcation radiolucency at all follow-up appointments. CONCLUSION CH with PEG performed better than CH with saline as capping material for pulpotomy of primary teeth. However, both combinations yielded clinical and radiographic results inferior to those of MTA alone.
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4.
[Hyperkalemia in heart failure: new solutions for an old problem].
Romani, S, Porcari, A, Fabris, E, Sinagra, G
Giornale italiano di cardiologia (2006). 2019;(10):543-551
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Abstract
Potassium is the main intracellular ion and its homeostasis is finely regulated by the renal and gastrointestinal tract. Renal failure and hyperkalemia are conditions commonly found in patients with heart failure, the result of a complex interaction between heart and kidney (e.g. cardio-renal syndrome) and the side effects of drugs commonly used for treating heart disease (e.g. renin-angiotensin-aldosterone system inhibitors). Although hyperkalemia increases the risk of heart conduction disorders and life-threatening arrhythmias, its prognostic significance in heart failure is uncertain. Hyperkalemia and progression of renal damage are the main limitations to the introduction and titration of heart failure therapies. New drugs for the prevention and chronic treatment of hyperkalemia allow the introduction and modulation of anti-neurohormonal therapies in patients with heart failure otherwise excluded from these treatments due to excessively high serum potassium levels.This review illustrates the pathophysiological, epidemiological and prognostic aspects of hyperkalemia and analyses the possible treatments for this condition in heart failure patients.
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Short-term antibacterial activity and compressive strength of biodentine containing chlorhexidine/cetirimide mixtures.
Deveci, C, Tuzuner, T, Cinar, C, Odabas, ME, Buruk, CK
Nigerian journal of clinical practice. 2019;(2):227-231
Abstract
BACKGROUND AND PURPOSE Aim is to evaluate the antibacterial activity and physical properties of Biodentine containing chlorhexidine (CHX)/cetrimide (CT) mixtures at 24 h. MATERIALS AND METHODS Powder formulations of CHX (2.5%) and CT (2.5%) were added to the powder of Biodentine and served as experimental groups (EXP). Antibacterial free groups were designed as control (CNT). The antibacterial acitivity (AB) (n = 5; for each) of disc-shaped specimens against Streptococcus mutans and Lactobacillius casei and compressive strength (CS) (n = 10; for each) tests used both for groups after 24 h after polymerization. STATISTICAL ANALYSIS USED Normality of data were tested with the Shapiro-Wilk test. Significant differences were analyzed with the Mann-Whintey U test for both the methods (agar disk diffusion and compressive strength) at a significance level of P < 0.05. RESULTS Significantly higher antibacterial effects were obtained in EXP groups compared to the CNTs for both bacteria after 24 h, distinctly (P < 0.01). No differences were found between groups regarding the CS values (P > 0.05). CONCLUSION Since the incorporation of 5% CHX/CT to the Biodentine exhibited acceptable antibacterial activity without hampering compressive strength values at 24 h, this combination could be a promising alternative for eliminating the residual bacteria for indirect pulp-capping therapies.
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The evaluation of MTA and Biodentine as a pulpotomy materials for carious exposures in primary teeth.
Çelik, BN, Mutluay, MS, Arıkan, V, Sarı, Ş
Clinical oral investigations. 2019;(2):661-666
Abstract
OBJECTIVE This study examined the effects of MTA and Biodentine on the clinical and radiographic success rates of pulpotomies performed on primary teeth with carious pulp exposures. MATERIALS AND METHODS This study was conducted with 44 mandibular primary molars requiring vital pulpotomy. Carious dentin surrounding the exposure site was used as the inclusion criteria for all teeth, which were randomly divided into two groups according to pulpotomy material [MTA group (n = 24), Biodentine group (n = 20)]. Treatment was followed up clinically and radiologically for 24 months. Pulp canal obliteration was not regarded as a failure. RESULTS Clinical and radiographic success rates at the end of 24 months were 100% for the MTA group and 89.4% for the Biodentine group. Success rates did not vary significantly between the groups (p = 0.646). Pulp canal obliteration was observed in two teeth (8.3%) in the MTA group at 6 months, but the teeth were found to be stabilized by 24 months. CONCLUSION The long-term clinical and radiographic success rates obtained in this study indicate that both MTA and Biodentine are appropriate options for pulpotomy treatment of primary teeth with carious exposure in patients whose teeth should be retained for long periods of time. CLINICAL RELEVANCE The etiology of exposure determines pulpal response, making it crucial to distinguish between mechanical and carious exposures. The carious exposure is presumed to be accompanied by severe inflammation, which makes the prognosis of treatment unpredictable. Biomaterials can be used especially in cases with carious pulp exposures.
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Potassium-lowering agents for the treatment of nonemergent hyperkalemia: pharmacology, dosing and comparative efficacy.
Bridgeman, MB, Shah, M, Foote, E
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2019;(Suppl 3):iii45-iii50
Abstract
Hyperkalemia represents a common and potentially life-threating electrolyte abnormality, a complication frequently observed in patients with heart failure, kidney disease, diabetes or in those receiving drug therapies influencing the renin-angiotensin-aldosterone system. Elevated serum potassium levels are often the result of impaired urinary potassium elimination, inadequate or reduced cellular potassium uptake, severe heart failure, use of medications influencing potassium levels in the circulation, or, more commonly, a combination of these factors. Strategies for the treatment of nonemergent hyperkalemia include the use of cation-exchange resins, polymers or other novel mechanisms of potassium trapping, including sodium polystyrene sulfonate, patiromer and sodium zirconium cyclosilicate. These agents differ in their pharmacology and mechanism of action, clinical efficacy, including onset and extent of potassium-lowering effect, dosage and administration, and potential safety and adverse effect profiles. In this review, an evaluation of these characteristics, including clinical evidence and safety concerns, in the management of nonemergent hyperkalemia will be explored.
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The kinetics of siderophore-mediated olivine dissolution.
Torres, MA, Dong, S, Nealson, KH, West, AJ
Geobiology. 2019;(4):401-416
Abstract
Silicate minerals represent an important reservoir of nutrients at Earth's surface and a source of alkalinity that modulates long-term geochemical cycles. Due to the slow kinetics of primary silicate mineral dissolution and the potential for nutrient immobilization by secondary mineral precipitation, the bioavailability of many silicate-bound nutrients may be limited by the ability of micro-organisms to actively scavenge these nutrients via redox alteration and/or organic ligand production. In this study, we use targeted laboratory experiments with olivine and the siderophore deferoxamine B to explore how microbial ligands affect nutrient (Fe) release and the overall rate of mineral dissolution. Our results show that olivine dissolution rates are accelerated in the presence of micromolar concentrations of deferoxamine B. Based on the non-linear decrease in rates with time and formation of a Fe3+ -ligand complex, we attribute this acceleration in dissolution rates to the removal of an oxidized surface coating that forms during the dissolution of olivine at circum-neutral pH in the presence of O2 and the absence of organic ligands. While increases in dissolution rates are observed with micromolar concentrations of siderophores, it remains unclear whether such conditions could be realized in natural environments due to the strong physiological control on microbial siderophore production. So, to contextualize our experimental results, we also developed a feedback model, which considers how microbial physiology and ligand-promoted mineral dissolution kinetics interact to control the extent of biotic enhancement of dissolution rates expected for different environments. The model predicts that physiological feedbacks severely limit the extent to which dissolution rates may be enhanced by microbial activity, though the rate of physical transport modulates this limitation.
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9.
Mineral Trioxide Aggregate Partial Pulpotomy Versus Formocresol Pulpotomy: A Randomized, Split-Mouth, Controlled Clinical Trial with 24 Months Follow-Up.
Nematollahi, H, Noorollahian, H, Bagherian, A, Yarbakht, M, Nematollahi, S
Pediatric dentistry. 2018;(3):184-189
Abstract
PURPOSE The purpose of this study was to evaluate the clinical and radiographic success rates of mineral trioxide aggregate partial pulpotomy (PP) compared to formocresol pulpotomy (FP) in human primary molars. METHODS In this randomized, controlled, split-mouth, clinical trial, 25 healthy five- to eight-year-olds, with 50 carious primary mandibular second molars lacking clinical and radiographic evidence of pulp pathology, were selected. The selected teeth were randomly assigned into two groups, PP and FP, for vital pulp therapy. Stainless steel crowns were placed as final restorations for both groups. Clinical and radiographic evaluation at six, 12, and 24 months used the following criteria for failure: pain; swelling; sinus tract; mobility; internal or external root resorption; furcation or periapical radiolucency; and widening of periodontal ligament space. The data were analyzed using a binary logistic generalized estimating equation model. RESULTS At the 12-month and 24-month follow-ups, one child and three children, respectively, were lost to follow-up. At the 24-month follow-up, the clinical, radiographic, and overall success rates of PP were 90.9 percent, 90.5 percent, and 81.8 percent versus FP success of 100 percent, 95.2 percent, and 95.2 percent, respectively. CONCLUSION There were no significant differences between clinical, radiographic, and overall success rate of mineral trioxide aggregate partial pulpotomy and formocresol pulpotomy overall 24 months.
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10.
Polylactic acid-based porous scaffolds doped with calcium silicate and dicalcium phosphate dihydrate designed for biomedical application.
Gandolfi, MG, Zamparini, F, Degli Esposti, M, Chiellini, F, Aparicio, C, Fava, F, Fabbri, P, Taddei, P, Prati, C
Materials science & engineering. C, Materials for biological applications. 2018;:163-181
Abstract
Polylactic acid (PLA), dicalcium phosphate dihydrate (DCPD) and/or hydraulic calcium silicate (CaSi) have been used to prepare highly-porous scaffolds by thermally induced phase separation technique (TIPS). Three experimental mineral-doped formulations were prepared (PLA-10CaSi, PLA-5CaSi-5DCPD, PLA-10CaSi-10DCPD). Pure PLA scaffolds constituted the control group. Scaffolds were tested for their chemical-physical and biological properties, namely calcium release, alkalinizing activity, surface microchemistry and micromorphology by ESEM, apatite-forming ability by EDX, micro-Raman and IR spectroscopy, thermal properties by differential scanning calorimetry, mechanical properties by quasi-static parallel-plates compression testing, porosity by a standard water-absorption method and direct-contact cytotoxicity. All mineral-doped scaffolds released biologically relevant ions (biointeractive). A B-type carbonated apatite layer (thickness decreasing along the series PLA-10CaSi-10DCPD>PLA-10CaSi>PLA-5CaSi-5DCPD>PLA) was detected on the surface of all the 28d-aged scaffolds. Surface pores of fresh scaffolds ranged from 10 to 20μm in pure PLA to 10-100μm in PLA-10CaSi. An increase in porosity was detected in 28d-aged pure PLA scaffolds (approx. 30% of material loss with decrease of the PLA chain length); differently, in mineral-doped scaffolds, the PLA degradation was balanced by deposition/nucleation of apatite. All scaffolds showed absence of toxicity, in particular PLA-10CaSi-10DCPD. The designed scaffolds are biointeractive (release biologically relevant ions), nucleate apatite, possess high surface and internal open porosity and can be colonized by cells, appearing interesting materials for bone regeneration.