Mechanism of strength increase for a hydrothermal porcelain.

OBJECTIVES: The objectives of this study were to verify the formation of a hydrolyzed surface layer on Duceram LFC, to determine the effects of such a layer on mechanical material properties, and to identify a specific mechanism responsible for any strength increase observed. METHODS: Specimens were fabricated from dentin porcelain by a vibration blotting technique and were prepared to have either blunt or sharp surface flaws. Half of the specimens underwent accelerated aging. Specimens were fractured in three-point flexure to measure their strength, and fractographic analysis was used to determine fracture toughness and residual surface stress. Surface hardness and elastic modulus were measured using a microindentation method. Porcelain surface topography was examined using atomic force microscopy, and Fourier transform infrared spectroscopy was used to determine the composition of the surface layer. RESULTS: The aging treatment modified the porcelain surface topography but did not create a layer with increased hydroxyl ion content. Porcelain strength increased upon aging, and the increase was proportional to initial flaw severity. The apparent fracture toughness of sharp flaw specimens increased to match that for specimens containing blunt flaws upon aging. Surface hardness and elastic modulus decreased upon aging. SIGNIFICANCE: Previous studies on the strength increase of hydrothermal porcelain were contradictory because a variety of specimen preparation procedures were used. This study resolves the apparent contradiction by determining the effect of specimen preparation on material strength.     

Examination of anticoagulation prescription among elderly patients with atrial fibrillation after in-hospital fall

Journal of Thrombosis and Thrombolysis - Mechanical fall is common among elders and has been associated with a lack of anticoagulant therapy among patients with atrial fibrillation (AF). However,...     

Drug-Silica Coassembled Particles Improve Antimicrobial Properties of Endodontic Sealers

IntroductionThe purpose of this study was to assess the antimicrobial activity and flow of root canal sealers after incorporating novel highly loaded antimicrobial drug-silica coassembled particles (DSPs).MethodsDSPs were synthesized through coassembly of silica and octenidine dihydrochloride (OCT) antimicrobial surfactant. DSPs were loaded (1% and 2% wt) into epoxy resin sealer (AH Plus [AH]; Dentsply DeTrey GmbH, Konstanz, Germany) or calcium silicate–based sealer (EndoSequence Bioceramic Sealer (BC); Brasseler, Savannah, GA). OCT release from DSP-modified sealers was determined using liquid chromatography. Antimicrobial activity of sealers against planktonic or biofilm form Enterococcus faecalis was assessed using direct contact and membrane restricted tests. Sealer flow was tested according to ISO6876:2012.ResultsOCT release from BC + 1% or 2% DSPs was above the minimum inhibitory concentration following 2 days throughout the 30-day experiment, whereas OCT release from AH + 1% or 2% DSP was significantly below the minimum inhibitory concentration against E. faecalis (4 μg/mL) over the whole 30-day experimental period. All materials (with or without DSPs) killed planktonic bacteria initially. AH ± 1% or 2% DSPs had no antimicrobial activity after 7 days. BC + 1% or 2% DSPs maintained antibacterial activity over the 30-day period. Both modified and unmodified sealers completely inhibited the growth of E. faecalis biofilms after 24 hours of contact. DSPs decreased the flow of AH and BC sealers; for AH, the reduction was proportional to the amount of DSPs added. All modified and unmodified sealers, except for AH + 2% DSPs, were within the acceptable limits of ISO 6876 flow tests.ConclusionsDSPs enhanced the antimicrobial performance of BC but not AH, whereas the material’s flow remained compliant with ISO 6876 standards. Depending on the sealer, DSPs may enhance antimicrobial efficacy in root canal treatment and potentially improve treatment outcome.     

Maxillary Anterior Teeth With Extensive Root Resorption Treated With Low-level Light-activated Engineered Chitosan Nanoparticles

IntroductionPhotoactivated chitosan-based nanoparticles can eliminate bacterial biofilm, inactivate endotoxins, improve resistance to biological degradation (resorption), and promote bone regeneration. This case is the first documentation to highlight the successful healing of teeth with extensive inflammatory root resorption (IRR) with periapical lesions using a combined surgical and nonsurgical root canal therapy using rose bengal functionalized chitosan nanoparticles (CSRBnp).MethodsA 17-year-old boy with extensive IRR of maxillary right canine (teeth #6), maxillary right lateral incisor (#7), maxillary right central incisor (#8), and maxillary left central incisor (#9) was treated with photoactivated CSRBnp, both intracanal as well as topically on resorptive defects and periapical lesions. The larger external resorptive defects on the root surfaces were restored with Biodentine, whereas the through-and-through periapical lesions were packed with sticky bone for Guided Bone Regeneration.ResultsAt 26 months of follow-up, the clinical, 2-dimensional (intraoral periapical radiographs) and 3-dimensional (cone-beam computed tomography) images showed absence of clinical symptoms, teeth mobility, arrested IRR, and significant osseous healing of the periradicular region. Postoperatively, the patient retraumatized thrice in relation to #7 resulting in horizontal root fracture, which showed type I pattern of root fracture healing in the follow-up.ConclusionsPhotoactivated chitosan-based nanoparticles can be a viable therapeutic option to hinder root resorption while enhancing healing outcomes in cases of severe IRR.     

Biofilm Formation within the Interface of Bovine Root Dentin Treated with Conjugated Chitosan and Sealer Containing Chitosan Nanoparticles

IntroductionThe purpose of this study was to assess biofilm formation within sealer-dentin interfaces of root segments filled with gutta-percha and sealer incorporated with chitosan (CS) nanoparticles with and without canal surface treatment with different formulations of CS.MethodsStandardized canals of 4-mm bovine root segments (N = 35) were filled with gutta-percha and pulp canal sealer incorporated with CS nanoparticles without surface treatment (group CS) or after surface treatment with phosphorylated CS (group PHCS), CS-conjugated rose bengal and photodynamic irradiation (group CSRB), or a combination of both PHCS and CSRB (group RBPH). The control group was filled with gutta-percha and an unmodified sealer. After 7 days of setting, specimens were aged in buffered solution at 37°C for 1 or 4 weeks. Monospecies biofilms of Enterococcus faecalis were grown on specimens for 7 days in a chemostat-based biofilm fermentor. Biofilm formation within the sealer-dentin interface was assessed with confocal laser scanning microscopy.ResultsIn the 4-week–aged specimens only, the mean biofilm areas were significantly smaller than in the control for the CS (P = .008), PHCS (P = .012), and RBPH (P = .034) groups. The percentage of the biofilm-covered interface also was significantly lower than in the control for the CS (P = .024) and PHCS (P = .003) groups. The CS, PHCS, and RBPH groups did not differ significantly.ConclusionsIncorporating CS nanoparticles into the zinc oxide–eugenol sealer inhibited biofilm formation within the sealer-dentin interface. This effect was maintained when canals were treated with phosphorylated CS, and it was moderated by canal treatment with CS-conjugated rose bengal and irradiation.     

Crystalloids,colloids, blood,blood products and blood substitutes

Understanding the physiology of fluid distribution within the human body is fundamental to the practice of anaesthetists and intensivists of all grades. There is a necessity to recognize the range of actions and consequences of the commonly infused intravenous fluids if safe patient care is to be provided. There are many historical and on-going trials surrounding fluid therapy and it is important for the physician to keep up to date with current guidelines.There is a continued drive to improve the safety of donor blood and prevent transfusion errors. Knowledge of how blood products are collected separated and stored is essential to prevent harm to patients through transfusions. Work in producing blood substitutes is progressing, but to date, trials have failed to market a product in Europe and the USA with an acceptable risk profile.     

Temporal-controlled Release of Bovine Serum Albumin from Chitosan Nanoparticles: Effect on the Regulation of Alkaline Phosphatase Activity in Stem Cells from Apical Papilla

Introduction

The controlled delivery of bioactive molecules is crucial for the regulation of stem cell differentiation. In this study, we examined the effects of temporal-controlled release of bovine serum albumin (BSA) from chitosan nanoparticles (CSnp) to regulate the alkaline phosphatase activity (ALP) in stem cells from apical papilla (SCAP).

Methods

BSA-loaded CSnp were synthesized by 2 methods to achieve the variant temporal-controlled release: (1) the encapsulation technique (BSA-CSnpI) and (2) the adsorption technique (BSA-CSnpII). After characterization of the size, charge, and release kinetics, SCAP were cultured in the presence of these bioactive molecule–loaded nanoparticles. SCAP viability was analyzed at 1, 7, 14, 21, and 28 days, and ALP activity was analyzed every 7 days until 21 days to determine the effect of these bioactive molecule–releasing nanoparticles on the cytotoxicity and differentiation potential, respectively.

Results

BSA-CSnpI and BSA-CSnpII presented distinct in vitro release profiles of BSA in a time-controlled manner. Cell viability was significantly enhanced over time in the presence of BSA-CSnpI and BSA-CSnpII (P < .01), when compared with BSA nonloaded CSnp. ALP activity was significantly higher (P < .01) in the presence of BSA-CSnpI after 3 weeks than in BSA-CSnpII.

Conclusions

BSA-loaded CSnps were synthesized and characterized in this study. Based on the physical/chemical interaction of BSA with CSnp (encapsulation or surface adsorption), different time-controlled release profiles were observed that influenced the ALP activity of SCAP in vitro. This study highlighted the potential of temporal-controlled bioactive molecule release technology in the differentiation of stem cells in dentin pulp regeneration.     

Assessment of contraceptive services in a maternity unit of a district general hospital in the UK.

A survey was undertaken to assess the quality of contraceptive services provided to women delivering in a District General Hospital. Separate questionnaires were given to the women and the midwives giving the contraceptive advice. Response rate of the survey was 87%. Thirty eight per cent of women reported having some discussion on contraception during antenatal period. All the women had received contraceptive advises during the postpartum period. Eighty one per cent of women felt that sufficient information and enough time was given to discuss contraception. However analysis of questionnaires indicated that most received information only on short-term contraceptive methods. Out of 64 midwives surveyed, 52 had attended a family planning course. However 37 of them had attended the course at least 3 years earlier. Thirty eight midwives felt that they have adequate knowledge to give advice but all of them reported that they should receive further training. There should be provision for comprehensive discussion regarding contraceptive options during both antenatal and postpartum periods. Midwives require regular training in family planning.