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11,618 result(s) for "Calcium compounds"
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Analysis of pulp histological response to pulpotomy performed with white mineral trioxide aggregate mixed with 2.25% sodium hypochlorite gel in humans: a randomized controlled clinical trial
This study aimed to evaluate the histological success of pulpotomy in primary molars using white mineral trioxide aggregate (WMTA) mixed with 2.25% sodium hypochlorite (NaOCl) gel and to evaluate in vitro its physical and chemical properties. The study had a clinical stage and an in-vitro stage. The clinical study was conducted with 24 patients aged 8–10 years. It was a randomized controlled trial to perform a histologic evaluation of pulp response following pulpotomy. Primary first molars were randomly assigned in split mouth model to control group—WMTA + distilled water (DW) or experimental group – WMTA + NaOCl gel. Teeth were extracted after 7, 30 or 90 days and submitted to histological analysis. The second stage was an in-vitro study to evaluate the physical and chemical properties of the two materials tested. SEM and EDX analyses and pH level evaluations were performed after 24 h and 28 days. The histological findings revealed that while WMTA + NaOCl gel group showed better odontoblastic integrity ( P  < 0.05), WMTA + DW group had more favorable outcomes in dentin bridge formation and pulp calcification ( P  < 0.05). Pulp tissue hemorrhage and pulp fibrosis were similar between them ( P  > 0.05). Regarding materials’ in vitro evaluation, the pH level indicated a higher initial pH for the WMTA + NaOCl gel group, which equalized after 28 days. SEM analysis initially showed a less homogeneous surface for WMTA + NaOCl gel, but it became similar after 28 days. EDX analysis indicated higher calcium and silicon percentages in the WMTA + NaOCl gel group initially, which increased in both groups after 28 days. Adding 2.25% NaOCl gel to WMTA enhanced odontoblastic integrity in both the short and medium term. In addition, it had a similar chemical composition, surface morphology, and alkalinity when compared to WMTA + DW mixture.
Biological impact of lead from halide perovskites reveals the risk of introducing a safe threshold
Regulations currently in force enable to claim that the lead content in perovskite solar cells is low enough to be safe, or no more dangerous, than other electronics also containing lead. However, the actual environmental impact of lead from perovskite is unknown. Here we show that the lead from perovskite leaking into the ground can enter plants, and consequently the food cycle, ten times more effectively than other lead contaminants already present as the result of the human activities. We further demonstrate that replacing lead with tin represents an environmentally-safer option. Our data suggest that we need to treat the lead from perovskite with exceptional care. In particular, we point out that the safety level for lead content in perovskite-based needs to be lower than other lead-containing electronics. We encourage replacing lead completely with more inert metals to deliver safe perovskite technologies. Halide perovskites are promising for next generation photovoltaic technology but their environmental impact has not been fully evaluated. Here Li et al. show that the lead from perovskites is ten times more dangerous than lead-containing electronics while tin perovskites are much less bioavailable.
Effects of sevelamer and calcium-based phosphate binders on mortality in hemodialysis patients
Elevated serum phosphorus and calcium are associated with arterial calcification and mortality in dialysis patients. Unlike calcium-based binders, sevelamer attenuates arterial calcification but it is unknown whether sevelamer affects mortality or morbidity. In a multicenter, randomized, open-label, parallel design trial we compared sevelamer and calcium-based binders on all-cause and cause-specific mortality (cardiovascular, infection, and other) in prevalent hemodialysis patients. A total of 2103 patients were initially randomized to treatment and 1068 patients completed the study. All-cause mortality rates and cause-specific mortality rates were not significantly different. There was a significant age interaction on the treatment effect. Only in patients over 65 years of age was there a significant effect of sevelamer in lowering the mortality rate. There was a suggestion that sevelamer was associated with lower overall, but not cardiovascular-linked, mortality in older patients. We suggest that further research is needed to confirm these findings.
Clinical and radiographic assessment of mineral trioxide aggregate with platelet rich fibrin as pulp capping biomaterials: a 12-month randomized trial
This study aimed to comparatively assess the clinical success and radiographic regenerative dentin formation of Platelet Rich Fibrin (PRF) and mineral trioxide aggregate (MTA) when used as direct pulp capping agents. This double-blinded two parallel armed randomized controlled clinical trial comprised the allocation of 108 patients with traumatically exposed dental pulp during the management of deep carious lesions by undergraduate students after fulfilling inclusion and exclusion criteria. Patients were randomized into two groups ( n  = 54 in each group) using computer-generated simple randomization, wherein one group Platelet Rich Fibrin (PRF) was prepared from patients’ blood samples and applied directly over exposed pulp followed by MTA application and in the other group MTA was applied directly over pulp exposure. In both groups, cavities were restored with resin-modified glass ionomer liner and resin composite restoration. The overall success of treatment was calculated at 6 and 12 months after assessing pulp sensibility, history of pain, tenderness on percussion and the existence of any periapical pathosis using in periapical radiographs. Moreover CBCT was used at 12 months to determine the presence or absence of dentin bridge as a secondary outcome. After 12 months follow-up, there was no statistically significant difference in overall success of pulp capping in both groups. As the both groups showed 92.59% success rate. CBCT evaluation of dentin bridge formation by Platelet Rich Fibrin (PRF) demonstrated a significantly higher percentage than that formed in cases treated with MTA alone ( p  < 0.001). Direct pulp capping with Platelet Rich Fibrin (PRF) exhibited a clinical and radiographic success rate comparable to that of MTA. Platelet Rich Fibrin (PRF) can be implemented as a direct pulp capping agent in forthcoming clinical applications.
Dislodgement resistance and structural changes of tricalcium silicate-based cements after exposure to different chelating agents
This study aimed to evaluate the dislodgement resistance and structural changes of different mineral trioxide aggregate cements (MTA) like Pro-Root MTA, Ortho MTA, and Retro MTA after exposure to sodium hypochlorite (NaOCl), NaOCl-Ethylenediaminetetraacetic acid (EDTA), 1-hydroxyethylidene-1, 1-bisphosphonate (Dual Rinse HEDP), and NaOCl-Maleic acid (MA). The root canal spaces of 150 dentine slices were obturated using tricalcium silicate cements and divided into 3 groups (n = 50): Group1: ProRoot MTA, Group2: Retro MTA, and Group3: Ortho MTA. The samples in each group were further subdivided into four experimental (n = 10) and one control groups (n = 10): 2.5% NaOCl-17% EDTA, Dual Rinse HEDP, 2.5% NaOCl-7% Maleic acid, 2.5% NaOCl, distilled water (control). The dislodgement resistance and structural changes of cements were measured. Use of DR HEDP resulted in higher dislodgement resistance compared to17% EDTA and 7% MA in the samples obturated with Ortho MTA and Pro-Root MTA (p<0.001). In Retro MTA group, samples treated with DR HEDP and 17% EDTA had higher dislodgment resistance compared to 7% MA (p<0.001). On microstructural and elemental analysis of all the three MTA cements, samples treated with 17% EDTA and 7% MA were more amorphous and granular when compared to DR HEDP, which was pettle shaped. Calcium level was decreased more in samples treated with 17% EDTA and 7% MA when compared to DR HEDP.
The effect of acidity on the physicochemical properties of two hydraulic calcium silicate-based cements and two calcium phosphate silicate-based cements
Background Bioceramic cements have been widely used in endodontic treatment. This study aimed to compare the microhardness, elastic modulus, internal microstructure and chemical compositions of Biodentine, WMTA, ERRM Putty, iRoot FS and IRM after exposure to PBS, butyric acid, and butyric acid followed by PBS. Methods Specimens of each material were prepared and randomly divided into 5 subgroups (n = 5): subgroup A: PBS (pH = 7.4) for 4 days, subgroup B: PBS (pH = 7.4) for 14 days, subgroup C: butyric acid (pH = 5.4) for 4 days, subgroup D: butyric acid (pH = 5.4) for 14 days, subgroup E: butyric acid for 4 days followed by 10 days in contact with PBS. The surface microhardness, elastic modulus, internal morphologic and chemical compositions of specimens were analyzed. Results The microhardness and elastic modulus values of all materials were significantly higher in the presence of PBS compared to exposure to butyric acid, with the same setting time ( P  < 0.01). After 4-day exposure to butyric acid followed by 10-day exposure to PBS, the microhardness values returned to the same level as 4-day exposure to PBS ( P  > 0.05). Biodentine showed significantly higher microhardness and elastic modulus values than other materials, while IRM displayed the lowest ( P  < 0.01). Conclusion Biodentine seems the most suitable bioceramic cements when applied to an infected area with acidic pH. Further storage at neutral pH, e.g. PBS reverses the adverse effects on bioceramic cements caused by a low pH environment.
Outcomes of root canal therapy or full pulpotomy using two endodontic biomaterials in mature permanent teeth: a randomized controlled trial
ObjectiveThe concept of minimally invasive endodontics recommends less-invasive vital pulp therapy (VPT) modalities over more aggressive traditional endodontic approaches in mature permanent teeth with carious pulp exposure, including irreversible pulpitis (IP) cases. Consequently, VPT needs to be compared with root canal therapy (RCT) in terms of treatment outcomes. This randomized clinical trial compares the results of full pulpotomy using two calcium-silicate cements, i.e., mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement, with RCT in mature permanent teeth.Materials and methodsA total of 157 carious pulp exposure cases in two academic centers with/without established IP were selected/included/randomly appointed to three study arms; (i) RCT (n = 51) as the reference treatment, (ii) pulpotomy with ProRoot MTA (PMTA; n = 55), and (iii) pulpotomy with CEM cement (PCEM; n = 51) as two alternative VPT treatments. Two-year clinical/radiographic results were the outcomes of interest. Data were statistically analyzed through the analysis of variance, chi-square, Fisher exact test, and Kruskal–Wallis.ResultsAt 2-year recall, 147 teeth were examined (6.4% dropout). All molars, except for one, were clinically functional/symptom-free, and there was no statistical difference between the three study arms (p = 0.653). The radiographic success rates in RCT, PMTA, and PCEM arms were 98%, 100%, and 97.9%, respectively, without statistically significant differences (p = 0.544).ConclusionIn the management of mature permanent teeth with/without established IP, all experimental groups exhibited equivalent/comparable results.Clinical relevanceSimple VPT using MTA/CEM can be suggested/recommended as a viable advantageous alternative to RCT for the management of carious pulp exposures with/without sign/symptoms of IP.
Histopathological and immunohistochemical characterization of pulp tissue reaction to ACTIVA BioACTIVE base/liner in primary teeth pulpotomy: a randomized clinical trial
Background Mineral trioxide aggregate (MTA) is the gold standard pulpotomy agent with some shortcomings, such as lengthy setting time, difficult manipulation, and a costly price. A new bioactive material, ACTIVA BioACTIVE Base/Liner, may prevail over these drawbacks. Aim The purpose of the study was to evaluate and compare the pulp reaction in primary teeth to ACTIVA BioACTIVE Base/Liner and conventional powder-liquid MTA (WhiteProRoot®MTA) as pulpotomy agents. Materials and methods Eighty primary first molars in children aged 7–9 years were assigned into two groups (40 molars/group) in which the pulpotomy procedure was done. The pulp tissue was dressed in ACTIVA BioACTIVE Base/Liner (group I) and MTA (group II). Twenty teeth from each group were extracted after 15 days, and the remaining twenty teeth in each group were extracted after 30 days. All teeth specimens underwent a decalcification treatment for histological and immunohistochemical assessment for fibronectin and osteopontin (OPN) expressions. Results Significant statistical differences were identified between ACTIVA BioACTIVE and MTA groups concerning the total scoring of pulp vascularity, pulp fibrosis, and presence or absence of pulp stone ( P  = 0.015, P  < 0.001, P  = 0.038, respectively), whereas a non-significant difference was noted concerning the odontoblastic layer organization. Fibronectin and OPN in both ACTIVA BioACTIVE and MTA groups were positive at the fibrotic and calcified areas. Conclusion ACTIVA BioACTIVE Base/Liner demonstrated encouraging outcomes concerning enhanced systemic tissue responses. Trial Registration ClinicalTrials.gov, NCT05300152, “Pulpotomy Medications in Primary Teeth”, Registered: 29/03/2022, https://clinicaltrials.gov/study/NCT05300152?cond=NCT05300152&rank=1
Toxicity of organometal halide perovskite solar cells
In the last few years, the advent of metal halide perovskite solar cells has revolutionized the prospects of next-generation photovoltaics. As this technology is maturing at an exceptional rate, research on its environmental impact is becoming increasingly relevant.
Clinical evaluation of the performance and safety of a new dentine substitute, Biodentine, in the restoration of posterior teeth — a prospective study
Objectives A multicentric randomized, 3-year prospective study was conducted to determine for how long Biodentine, a new biocompatible dentine substitute, can remain as a posterior restoration. Materials and methods First, Biodentine was compared to the composite Z100®, to evaluate whether and for how long it could be used as a posterior restoration according to selected United States Public Health Service (USPHS)’ criteria (mean ± SD). Second, when abrasion occurred, Biodentine was evaluated as a dentine substitute combined with Z100®. Results A total of 397 cases were included. This interim analysis was conducted on 212 cases that were seen for the 1-year recall. On the day of restoration placement, both materials obtained good scores for material handling, anatomic form (0.12 ± 0.33), marginal adaptation (0.01 ± 0.10) and interproximal contact (0.11 ± 0.39). During the follow-up, both materials scored well in surface roughness (≤1) without secondary decay and post-operative pain. Biodentine kept acceptable surface properties regarding anatomic form score (≤1), marginal adaptation score (≤2) and interproximal contact score (≤1) for up to 6 months after placement. Resistance to marginal discoloration was superior with Biodentine compared to Z100®. When Biodentine was retained as a dentine substitute after pulp vitality control, it was covered systematically with the composite Z100®. This procedure yielded restorations that were clinically sound and symptom free. Conclusions Biodentine is able to restore posterior teeth for up to 6 months. When subsequently covered with Z100®, it is a convenient, efficient and well tolerated dentine substitute. Clinical relevance Biodentine as a dentine substitute can be used under a composite for posterior restorations.