Biomedical subjects
Publications and source records attributed to G E King.
A technique is presented for making an acrylic resin core for processing silicone facial prostheses. This technique ensures a durable core that can be used to make multiple prostheses. The core resists fungal growth during storage and creates a smooth, easily cleanable internal surface for a facial prosthesis. The core also permits a controllable thickness and therefore a lighter prosthesis.
The value and success of a well-fitting and anatomically correct prosthesis are compromised if the color does not match the adjoining tissue. Color and color science are reviewed to help develop a simplified acrylic resin shade guide to aid in fabricating acrylic resin facial prostheses. This guide will help the clinician obtain a good intrinsic shade and minimize extrinsic coloration.
Polyvinylchloride plumbing parts provide a readily available source of material to use in making facial prostheses. Inexpensive pipe fittings (end cap attachments and closet flanges) can be combined to provide a durable container for stone molds that can be tightened in a strong curing press. The entire unit can be cured in a microwave oven in 30 minutes.
A simplified technique for preparing, under a vacuum, a polyurethane lining for a facial prosthesis is described. A previously presented technique strengthened the prosthesis and allowed it to be attached with a water-based adhesive. This technique eliminates wrinkling, simplifies bonding, allows multiple linings to be made at the same time, conserves time and cost, and improves predictability of the results.
In May 1988, California became the first state to make aeromonas infection a reportable condition, thereby permitting the first population-based study of the epidemiology of infection caused by Aeromonas organisms. Case investigations were carried out on 219 of the 280 patients whose infections were reported during the first year of notification. The overall incidence rate for Aeromonas isolation was 10.6 cases per 1 million population. The gastrointestinal tract was the most commonly reported site from which Aeromonas was isolated (81%), with wounds being the next most common source (9%). Five (2%) of the 219 patients died; all five had serious underlying medical conditions apart from aeromonas infection. No common-source enteric outbreaks were reported. The high rate of gastrointestinal symptoms and isolation of organisms from medically vulnerable patients and the fact that other bacterial enteric pathogens were rarely isolated from symptomatic patients support evidence from previous studies that Aeromonas is an enteric pathogen. The evidence from these case reports in California suggests that aeromonas infections are not an important public health problem and are largely nonpreventable. Thus, public health surveillance is not necessary and mandatory reporting has been discontinued.
In this study, a technique is described by which large obturators can be retained with an acrylic resin head plate. The technique entails attaching the prosthesis to an acrylic resin plate with a 2-mm-diameter wire and then attaching the plate to the patient's forehead with skin tape.
The advantages of multidisciplinary treatment planning of head and neck cancer patients is described. Planning rehabilitation concurrently with curing the malignancy results in the most effective application of treatment modalities coordinated with rehabilitative care. Concentrated multidisciplinary treatment reduces post treatment morbidity by shortening recovery and rehabilitation time.
The addition of 20 vol% and 40 vol% filler significantly (p less than 0.05) reduced the density and impact strength of the denture base resin when compared with resin without filler. There was no significant difference in the density or impact strength between 20 vol% and 40 vol% filled specimens. Desiccation significantly (p less than 0.05) decreased the density and impact strength of denture base resin regardless of the presence or amount of filler added. The addition of microsphere filler decreased the denture base resin density by 8% to 9%, which may not reduce the weight of prostheses enough to be clinically significant. The impact strength was reduced by approximately 30%.
To identify causes and risk factors for pregnancy-related mortality in New York City, we analyzed 224 pregnancy-related deaths that occurred from 1980 to 1984. The leading causes of death were ectopic pregnancy complications, embolism, intrapartum cardiac arrest, and hypertension. Mortality ratios were determined by comparing the characteristics of the women whose death was pregnancy-related with those of women who had survived delivery of a live infant in New York City during the same period. Black and Hispanic women had mortality ratios that were respectively 4.2 and 2.0 times higher than those for white, non-Hispanic women. In comparison with women aged 20 to 24, those older than 30 were more than twice as likely to die from pregnancy-related causes, and those older than 40 were five times as likely to do so. Other factors that were associated with an increased risk of pregnancy-related mortality included 9 to 11 years of education, lack of private medical insurance, more than five previous pregnancies, and fewer than five prenatal visits. This study suggests that changes in current maternal-health and family-planning services will be required to achieve further reductions in preventable pregnancy-related mortality.
Because of increased measles incidence in the United States during 1989 and 1990 and the recent finding of genomic differences between vaccine virus and contemporary wild measles viruses, we conducted a study to determine whether the current measles vaccine had become less effective. Household secondary attack rates for 203 California children ages 1 to 5 years were 4.2 and 77.8% for vaccinated and unvaccinated children, respectively, and the vaccine efficacy was 95% (95% confidence interval: 89%, 97%). The protective efficacy for postexposure vaccination and use of IG were both low, 4% (95% confidence interval: less than 0, 36%) and 8% (95% confidence interval: less than 0, 59%), respectively. The measles vaccine efficacy found in this study is similar to those obtained in previous years and indicates that the measles epidemic of 1989 to 1990 occurred despite high vaccine effectiveness.
Three primers were evaluated to determine their effect on the strength of the bond when Silastic 891 is cured to poly(methylmethacrylate). Silastic cured directly to the poly(methylmethacrylate) without a primer was used as a control. All primers increased the bond strength but one of the primers was definitely superior to the others.
Electrotherapy and hyperbaric oxygen therapy have been added to physical therapy to treat patients with postsurgery and radiation sequelae. Problems of reduced oral opening and range of head movement, soft tissue necrosis, osteoradionecrosis, and delayed wound healing were addressed in 37 patients over a 3-year period. Of this group, 16 irradiated maxillary resection patients were specifically followed up to determine the effectiveness of the new modalities on improving reduced oral opening. Although healing and the quality of the soft tissues showed marked improvement there was no significant improvement in oral opening.
The indications, design, and advantages of the labial plate major connector as compared with the labial and lingual bar major connector are reviewed. The mechanical principles of increased rigidity and strength are discussed. The article suggests that the labial plate major connector may have an advantage over the labial bar major connector and should be considered when a labial connector is indicated.
To find an alternative to the stigmata of abdominal colostomy, an artificial anal sphincter (utilizing the currently available artificial urinary sphincter) was implanted around an end perineal colostomy following standard abdominal perineal resection. Of 13 swine, 7 completed full evaluation with working sphincters, 3 animals died prematurely of unrelated causes, and 3 animals were sacrificed due to sphincter slough before inflation was begun. Seven animals had long-term evaluation of the sphincter for 2 to 6 months' duration. In 5 animals (72%) there was complete fecal continence; one animal (14%) had occasional partial incontinence and one had total incontinence, both due to sphincter malfunction from breakage of the connecting tab. Two of the seven animals had delayed slough of the sphincter after 2 months and 4.5 months of success, and 2 animals had erosion of the intraperitoneal balloon reservoir into the small bowel. In addition, 5 of 9 (55%) control pumps were complicated by skin erosion or infection; all were relocated successfully. The fact that an intact artificial anal sphincter can provide excellent continence demonstrates that this concept of perineal placement for bowel control is valid. Refinements in the device to prevent tab breakage, investigation of correct sphincter pressures to prevent sloughing, and better sites for implantation of the pump and balloon reservoir are requisite solutions for a fully implantable system to restore near-normal bowel function after radical abdominal perineal resection.
This paper presents the results of a study designed to determine (1) if advancement of a periodontal probe under a given force against healthy gingiva differed from its advancement under a similar force, against inflamed gingiva, and (2) to select the diameter which best distinguishes healthy gingiva from that which is inflamed to varying degrees. The teeth of eight beagle dogs were cleaned three times per week for two months until a Gingival Index (GI) of 0 and gingival fluid flow (GFF) of 9 or less, as measured by the Periotron, were obtained. Probes of diameters 0.4, 0.6, 0.7, and 0.8 mm were advanced perpendicularly against the attached gingiva in the incisor, premolar, and molar regions by an electromechanical device which simultaneously plotted force versus displacement following initial contact of the probe tip with the gingiva. These forces ranged from 0.1 to 0.9N. This process was repeated in the same animals following cessation of plaque control measures when the GI reached a value of 1 and GFF reached levels of 10 to 19. It was repeated again following placement of an irritating ligature when GI reached 2 and GFF greater than 20. An analysis of covariance showed significant differences between all three levels of health and disease for all probe diameters. F values for the 0.6 mm probe were highest at all probing forces indicating that this diameter most consistently discriminated variation of gingival health status.
This study was undertaken to determine the effect of gingival inflammation and probing pressure on probe tip placement in relation to the base of the gingival crevice and the most coronal connective tissue attachment fibers. Nine young male beagle dogs were divided into three groups as determined by clinical status of the gingiva following implementation of a protocol designed to produce gingival health and disease. An electromechanical device was used to advance 0.6 mm diameter probes into the facial gingival crevices of selected teeth and to obtain force-displacement curves. The instrument stopped the probe at pressure of either 80, 160, 320, 640, 1280, or 2560 kPa which were randomly allocated to 12 test teeth in each dog. After the probe came to rest, it was attached to the tooth. When all 12 probes were attached, the animal was sacrificed. Blocks consisting of gingiva, probe, and tooth were processed to obtain two buccolingual sections, one containing the probe and the other immediately adjacent to it. Clinical and histometric measurements were performed and the data evaluated. Although three groups of animals were discernable by clinical criteria, only two groups, health and disease, could be formulated based on the degree of histologic inflammation. The histologic grouping was used in data analysis. Histometric distances from the cemento-enamel junction to the base of the crevice (cJ), to most coronal connective tissue attachment (cC) and to the probe tip (cP) all increased with change from health to disease. However, changes in health/disease did not influence difference between distances (cP-cJ,cP-cC).(ABSTRACT TRUNCATED AT 250 WORDS)
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