Browsing by Author "Hancock, E. Brady"

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    Digital Microradiography: In Vitro Validation of a Novel Imaging Technique
    (2004) Yip, Gary Ka Fai; Roberts, W. Eugene; Everett, Eric; Garetto, Lawrence P.; Hancock, E. Brady; Kowolik, Michael J.; Parks, Edwin T.; Platt, Jeffrey A.; Zunt, Susan L.
    Microradiography has been widely used in mineralized tissue research in determining the mineral content within the specimens being studied. There are considerable limitations of this ageing gold standard such as unavailability of the high-resolution spectroscopic plates and prolonged imaging and processing times. The present study aimed at developing and validating a novel digital microradiographic technique that is not restricted by the limitations of conventional microradiography. Reproducibility of digital microradiography was investigated by studying 4 repeated images of 10 randomly selected sectioned implant-bone specimens acquired by 2 examiners over 2 weeks. The acquired images were analyzed by both manual and automated digital subtractions. Correlation between digital and conventional microradiography was performed by digital subtraction of 23 matching images acquired by both microradiographic techniques. A comparison between manual and automated digital subtraction enabled evaluation of the influence of the digital subtraction protocols on the results of the subtraction. A direct digital microradiographic technique has been developed which does not require analogue recording medium and film processing. The robustness of the digital microradiography was evidenced by the narrow range of means and standard deviations for intra- and inter-examiner reproducibility. The intra-examiner means and standard deviations ranged from 126.54-128.42 and 4.11-5.34 respectively. The inter-examiner means and standard deviations ranged from 126.71-129.87 and 4.68-5.70 respectively. The detection threshold for the digital microradiography was 5 gray scales or 3.9 percent, which was comparable to digital radiography. The high concordance between conventional and digital microradiography was demonstrated by the mean and standard deviation of 8.69 and 1.75 gray scales respectively. There was a statistically significant difference between the results obtained by manual and automated digital subtraction, but the clinical significance is yet to be determined.
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    Early Detection of Dietary-Induced Periodontal Bone Loss and the Effect of Flurbiprofen Administration in the Syrian Hamster
    (1991) Child, Michael E.; Roberts, W. Eugene; Shanks, James C.; Stookey, George K.; Hancock, E. Brady; Garetto, Lawrence P.
    Root surface caries is an increasing problem in the United States as more of the population are retaining their teeth to an older age. The disease requires the recession of gingival tissue and resorption of alveolar bone prior to exposure of the root surface. Animal models for root surface caries provide a means to investigate the etiology and treatment of the disease. The Golden Syrian hamster has been used as a model, and alveolar bone loss and root exposure are induced by feeding the animals a high glucose diet. Significant bone loss, when compared to control groups, is usually detected within five weeks. At present, the use of non-steroidal anti-inflammatory drugs in the treatment of periodontal disease is an area of great interest. As there is a role of host response in the alveolar bone destruction seen in periodontitis, inhibition of this prostaglandin-mediated process may provide a means of treatment. Flurbiprofen (Ansaid™, Upjohn Co., Kalamazoo, Ml) has been widely studied and appears to inhibit this bone loss in a variety of animals, including man. The purposes of the study were to determine if the early alveolar bone loss occurring after three, four and five weeks' exposure to the high carbohydrate diet could be quantitated with fluorescent bone labels, and if this bone loss could be inhibited by daily administration of flurbiprofen. The animals received a series of four intraperitoneally-injected fluorochrome labels over a one-month period, then were fed ground lab chow, the high carbohydrate MIT-200GI diet or the MIT-200GI diet plus flurbiprofen. At the end of three, four and five weeks, animals were euthanized, and the mandibles were prepared for analysis. Statistical analysis of gross and histomorphometric measurements detected no significant differences between the experimental groups. It is suspected that the diets failed to produce periodontal disease in this experiment, possibly due to changes in the oral microflora caused by administration of tetracycline as the final bone label. There was much variation in the presence of bone labels, but they were able to provide the growth velocity of the alveolar complex. Flurbiprofen administration produced no measurable effects, but the animals did tolerate the dosage given. Future studies should consider variation of the labels and a different route of administration.