RESUMEN

The conversion of polymer waste, food waste, and biomasses through thermochemical decomposition to fuels, syngas, and solid phase, named char/biochar particles, gives a second life to these waste materials, and this process has been widely investigated in the last two decades. The main thermochemical decomposition processes that have been explored are slow, fast, and flash pyrolysis, torrefaction, gasification, and hydrothermal liquefaction, which produce char/biochar particles that differ in their chemical and physical properties, i.e., their carbon-content, CHNOS compositions, porosity, and adsorption ability. Currently, the main proposed applications of the char/biochar particles are in the agricultural sector as fertilizers for soil retirement and water treatment, as well as use as high adsorption particles. Therefore, according to recently published papers, char/biochar particles could be successfully considered for the formulation of sustainable polymer and biopolymer-based composites. Additionally, in the last decade, these particles have also been proposed as suitable fillers for asphalts. Based on these findings, the current review gives a critical overview that highlights the advantages in using these novel particles as suitable additives and fillers, and at the same time, it shows some drawbacks in their use. Adding char/biochar particles in polymers and biopolymers significantly increases their elastic modulus, tensile strength, and flame and oxygen resistance, although composite ductility is significantly penalized. Unfortunately, due to the dark color of the char/biochar particles, all composites show brown-black coloration, and this issue limits the applications.

RESUMEN

This article aimed to evaluate whether normal osseointegration occurs in immediate loading following secondary stabilization obtained by means of conical copings and adaptation of patients' old dentures. Two clinical cases of immediate loading of implant-supported prostheses in the edentulous mandible are presented. Prostheses were positioned within 24 hours, with secondary splinting of primary conical copings screwed onto implants. For this purpose, the patients' old removable prostheses were adapted and lined to fit within the secondary acrylic resin copings, which perfectly matched the primary copings screwed onto the implants and milled to 2 degrees.

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RESUMEN

This report describes the rehabilitation of a patient who was completely edentulous in the mandible with a removable prosthesis supported by implants on four Straumann Wide-Neck implants placed in the positions of the canines and second molars. The Cagliari modified conometry technique was developed to improve and simplify anchorage systems based on conical copings in a removable prosthesis supported by implants. The connection of the removable prosthesis to the implants is obtained by primary conical copings, which are screwed to the implants, coupled to secondary copings equipped with plastic friction devices (Arch-Friction-Soft, Dental Konos). After the secondary copings are positioned on the primary copings, the secondary copings are fixed with acrylic resin to the removable prosthesis in the mouth, with the goal of passive fit. The prosthesis produced with this method is not a classic implant-supported overdenture but is a removable prosthesis completely supported by implants that is shaped like a fixed prosthesis. This type of prosthesis is extremely stable and has modular retention (plastic friction), creating ideal conditions for oral hygiene. The stability of this type of prosthesis results in psychologic comfort and masticatory performance similar to that of a fixed prosthesis but with the hygiene, esthetics, and lower expense of an overdenture.

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