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Sinus lift bone grafting has expanded the use of dental implants in reconstructions of the atrophic maxilla. Potential problems include sinus membrane tear, which can lead to graft infection and early failure. Attempts at managing sinus membrane perforations are often limited by difficulty of access, as well as by the friability of the soft tissue lining the sinus. Various techniques have been proposed for managing such membrane tears. The use of fibrin adhesive, however, may present a potential solution in such situations. This article reports our experience with the use of fibrin adhesive in sinus lift procedures, as well as on its autologous preparation.

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Nondecalcified histologic sections (from a cadaver) of 12 IMTEC implants in four jaw quadrants 1 year after surgery showed significant osseointegration. Microscopically, no apparent difference was observed in new bone growth and osseointegration in those implants placed in the maxilla or mandible, or between titanium plasma-spray-coated (TPS) implants and TPS-treated implants coated with hydroxyapatite. Areas in which implants were placed through the bony floor of the maxillary sinus showed new bone growth above the normal level of the floor of the sinus around the implants and into mechanical retention holes. Small penetrations of the maxillary sinus membrane or the lingual plate of the mandible did not affect the function of the implants, nor did they cause any symptoms. A vertical component of soft tissue around the cervical part of the osseointegrated implants, noted in histologic sections to be as much as 5 mm below the crest of the alveolar bone in at least one area, was not discernible radiographically even when 5-mm-thick sections of bone containing the implants were radiographed.

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We used standard 2,450-MHz microwave irradiation to achieve sterilization of hydrophilic contact lenses contaminated with a variety of bacterial, fungal, and viral corneal pathogens. A three-dimensional rotisserie was used to overcome the problem of "cold spots" within the microwave oven. The contact lenses became dehydrated in approximately two minutes. Rehydration with normal saline restored their shape and appearance. The time necessary to prohibit all growth of the bacterial and fungal organisms studied ranged from 45 seconds to eight minutes. All viral contaminants were completely inactivated after four minutes of microwave exposure. Refractive properties were unaffected after 101 exposures to microwaves for ten minutes. Slit-lamp examination and scanning electron microscopy disclosed minute particles on the surface of these contact lenses but no damage to the lens matrix from irradiation.

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Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

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This study has shown that representative fungi, viruses, and aerobic and anaerobic bacteria, including spore formers, can easily be killed in a conventional microwave oven with proper modifications. Metal instruments, including air turbine handpieces and burs, and acrylic dentures can be sterilized in short periods. Consistent sterilization can be accomplished only if the items to be sterilized are rotated in a three-dimensional manner throughout the microwave cavity. Arcing back to the magnetron and damage to the microwave oven are prevented by placing a radar absorbent material within the oven and with proper insulation of the item to be sterilized.

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A simple protocol has been developed for recycling plastic tissue culture vessels. The killing properties of microwaves were used to decontaminate plastic tissue culture vessels for reuse. Nine bacterial cultures, four gram-negative and five gram-positive genera, including two Bacillus species, were used to artificially contaminate tissue culture vessels. The microwaves produced by a "home-type" microwave oven (2.45 gHz) were able to decontaminate the vessels with a 3-min exposure. The same exposure time was also used to completely inactivate the following three test viruses: polio type 1, parainfluenza type 1 (Sendai), and bacteriophage T4. The recycling procedure did not reduce the attachment and proliferation of the following cell types: primary chicken and turkey embryo, HEp-2, Vero, BGMK, and MK-2.

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Use of microwave irradiation has been evaluated for the in situ fixation of cells grown in tissue culture prior to fluorescent antibody staining. The results show total retention of cell protein in the matrix with microwave fixation, whereas 40-50% of the protein is lost during conventional formaldehyde fixation. Fluorescent antibody staining of cells shows that this protein loss reflects cell loss. A further advantage of microwave fixation is that photometric quantitation of fluorescence appears possible by random scanning of fluorescent antibody stained populations.

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