ABSTRACT
BACKGROUND: The reuse of implant healing abutments is common in dental practice. Effective elimination of bacteria and viruses is accomplished by conventional sterilization. The aim of this work was to explore the eventual survival of microorganisms on sterilized healing abutments and to rule out the presence of transmissible organic material after standard procedures. MATERIAL AND METHODS: A total of 55 healing abutments previously used in patients will be washed and sterilized in a steam autoclave at 121 C for 15 min. Each healing abutment will be cultured in Brain Heart Infusion broth (BHI) under strict aseptic conditions. Besides, two control groups will be included: one of 3 unused healing abutments, and the other of just medium. After 10 days at 37°C under a 5% CO2 100 µl of the broth will be plated on solid media (Brain Infusion Agar, BHIA) and Columbia Blood agar to test for sterility. The remaining volume will be centrifuged, the sediment fixed, and a Gram stain performed to discard the presence of non-cultivable microorganisms. Moreover, to determine the presence of remaining organic material after the cleaning and sterilizing treatments, the bioburden will be determined by measuring total organic carbon (TOC) in another 10 previously used healing abutments, cleaned and sterilized, that will be submerged in Milli-Q water and sonicated. RESULTS: No bacterial growth was detected on any of the 58 cultured abutments, indicating that the sterilization was completely satisfactory in terms of removal of live bacteria or spores. Nevertheless, significant amounts of organic carbon may still be recovered (up to 125,31 µg/abutment) after they have been sterilized. CONCLUSIONS: Significant amounts of the bioburden remained adhered to the surfaces in spite of the cleaning and sterilization procedures. Taking into account our results and data from other authors, the presence of infectious particles on the reused healing abutments such as prions cannot be ruled out.
Subject(s)
Dental Abutments , Dental Implants , Humans , Sterilization , Surface Properties , TitaniumABSTRACT
Novel additive manufacturing processes are increasingly recognized as ideal techniques to produce 3D biodegradable structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. With regard to the mechanical and biological performances of 3D scaffolds, pore size and geometry play a crucial role. In this study, a novel integrated automated system for the production and in vitro culture of 3D constructs, known as BioCell Printing, was used only to manufacture poly(ε-caprolactone) scaffolds for tissue engineering; the influence of pore size and shape on their mechanical and biological performances was investigated. Imposing a single lay-down pattern of 0°/90° and varying the filament distance, it was possible to produce scaffolds with square interconnected pores with channel sizes falling in the range of 245-433 µm, porosity 49-57% and a constant road width. Three different lay-down patterns were also adopted (0°/90°, 0°/60/120° and 0°/45°/90°/135°), thus resulting in scaffolds with quadrangular, triangular and complex internal geometries, respectively. Mechanical compression tests revealed a decrease of scaffold stiffness with the increasing porosity and number of deposition angles (from 0°/90° to 0°/45°/90°/135°). Results from biological analysis, carried out using human mesenchymal stem cells, suggest a strong influence of pore size and geometry on cell viability. On the other hand, after 21 days of in vitro static culture, it was not possible to detect any significant variation in terms of cell morphology promoted by scaffold topology. As a first systematic analysis, the obtained results clearly demonstrate the potential of the BioCell Printing process to produce 3D scaffolds with reproducible well organized architectures and tailored mechanical properties.
Subject(s)
Biocompatible Materials/chemistry , Bioprinting/methods , Mesenchymal Stem Cells/cytology , Polyesters/chemistry , Tissue Engineering/instrumentation , Tissue Scaffolds , Cell Adhesion , Cell Proliferation , Cell Survival/drug effects , Compressive Strength , Humans , Materials Testing , Mesenchymal Stem Cells/drug effects , Polyesters/pharmacology , PorosityABSTRACT
UNLABELLED: The voluntary discontinuation of dialysis by patients is a common mode of death in dialysis programmes. Unfortunately the Spanish experience has not been related in the nephrological literature. Initiation of, and withdrawal from, dialysis pose ethical questions for medicine in the 21st century. The dialysis population is aging and they have multiple medical problems. The choice may be between prolongation of quantity or quality of life. We evaluated a protocol for initiation of dialysis in patients with end stage renal failure and their subsequent withdrawal. We determined the factors predicting withdrawal of dialysis and revised the protocol to take account of these. We carried out an opinion poll of doctors and nurses about the effectiveness of the protocol. We studied prospectively the reasons for death of patients in the last seven years. RESULTS: Thirty patients were withdrawn from dialysis out of 116 who died during treatment by hemodialysis or continuous ambulatory peritoneal dialysis (CAPD) in the last seven years. Vascular nephropathy is the principal disease predicting withdrawal from dialysis; the main precipitating cause is mental incapacity. The availability of a protocol for withdrawal of dialysis is well received by doctors and nurses and it engenders moral and legal calm when facing difficult decisions. Twenty-six per cent of deaths on regular dialysis are the result of withdrawal of treatment.
Subject(s)
Euthanasia, Passive , Kidney Failure, Chronic/therapy , Organizational Policy , Refusal to Treat , Renal Dialysis , Terminal Care/organization & administration , Adult , Aged , Aged, 80 and over , Attitude of Health Personnel , Cardiovascular Diseases/mortality , Cause of Death , Comorbidity , Dementia/epidemiology , Ethics, Medical , Euthanasia, Passive/psychology , Family , Female , Humans , Informed Consent , Kidney Failure, Chronic/mortality , Male , Medical Futility , Mental Competency , Middle Aged , Multiple Organ Failure/mortality , Neoplasms/mortality , Nurses/psychology , Patient Advocacy , Peritoneal Dialysis, Continuous Ambulatory , Physicians/psychology , Prospective Studies , Right to Die , Spain/epidemiology , Treatment Refusal/statistics & numerical dataABSTRACT
La retirada de diálisis no es motivo de investigación ni de tratamiento habitual en la literatura nefrológica española. Es un tema de debate que conlleva disyuntivas de tipo ético. Su presentación es frecuente actualmente en la clínica diaria. Con la prolongación de expectativas de vida de los pacientes, aumentan los dilemas acerca de la prolongación de esa vida en las mínimas condiciones de calidad.Se comprueba la utilidad de un protocolo de entrada/retirada de pacientes con insuficiencia renal crónica terminal, diseñando los parámetros pronósticos de retirada de diálisis, y revisando los parámetros que inciden en la toma de decisión de esa retirada. Se realiza una encuesta a los profesionales sobre la efectividad del protocolo. Se revisan prospectivamente las causas de muerte acaecidas en los últimos siete años.Los resultados muestran 30 pacientes retirados del total de 116 enfermos fallecidos durante ese tiempo. La nefropatía vascular es la enfermedad que plantea con mayor frecuencia la retirada de diálisis, siendo la causa inmediata la incapacidad mental.La disponibilidad de un protocolo de retirada de diálisis confiere un aceptable grado de satisfacción entre los profesionales y les da tranquilidad moral y tal vez legal, a pesar del vacío existente en ese sentido, ante unas tomas de decisiones eventualmente conflictivas, dado que un 26 por ciento de los fallecimientos son debidos a esa retirada. (AU)
