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Biomedical subjects

S J Zeichner

Publications and source records attributed to S J Zeichner.

7 recordsLinked to original sources
PubMed1991

Studies on focal alveolar bone healing with technetium (Tc)-99m labeled methylene diphosphonate and gold-collimated cadmium telluride probe.

The benefit of using a collimator for a miniaturized cadmium telluride probe was evaluated by monitoring the bone-healing processes for 13 weeks after the induction of small iatrogenic alveolar bone lesions in one side of the mandible in beagles. Technetium (Tc)-99m labeled methylene diphosphonate (200 to 300 MBq, 5.1 to 8.1 mCi, in a solution of 0.5 to 1 ml, intravenously) was used as a bone-seeking radiopharmaceutical. The radioactivity over the bone lesion (L) and the contralateral normal site (C) in the mandible were measured between 1.5 and 2 hours after injection of the tracer, and the activity ratio L/C served as an index of relative bone uptake. A study of six dogs revealed that the healing response to a hemispheric bone defect of 2 mm diameter in the cortical bone could not be detected by an uncollimated probe, and in a repeated study in two dogs the use of a gold collimator (5 mm in diameter, 5 mm in length) did not increase the L/C ratio significantly. A second study in six dogs with 5 mm lesions showed that although systematic trends in the time courses of the L/C ratio obtained both with and without the collimator could be demonstrated, the L/C ratio of collimated versus uncollimated measurements was significantly (p less than 0.005) increased. In three of the latter six dogs, abscesses developed after 9 weeks, leading to a second increase (p less than 0.05) of the L/C ratio with collimation compared with the noninflammation group; without collimation no significant (p greater than 0.15) difference between the two groups could be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗
PubMed1989

Cephalometric norms for orthognathic surgery in black American adults.

Normal values for the Cephalometrics for Orthognathic Surgery (COGS) analysis for American black adults were developed in this study. The cephalometric radiographs of 33 black American adults with ideal dentitions were analyzed, and a statistical description of their hard and soft tissue cephalometric measurements is presented. In addition, mean values for black American adults were compared with those of white American adults. In black subjects, there was greater maxillary skeletal prognathism, skeletal lower face height, skeletal facial convexity, lower incisor proclination, anterior dental heights, upper and lower lip lengths, and soft tissue thickness of the lips and chin than in white subjects. There was less nasal depth and projection, less bony chin depth, and a smaller nasolabial angle in black subjects. The results of this study may be useful in providing racially specific cephalometric values for diagnosis and treatment planning for orthognathic surgery in American black adults.

Adolescent↗
PubMed1989

Efficacy of dental radiographic practices: options for image receptors, examination selection, and patient selection.

Many technical factors and treatment philosophies affect the way dental radiology is practiced. Some, like minimum tube filtration, are legislated. Others, like proper darkroom techniques, are universally acknowledged as essential. Still others, like the selection of an image receptor and the selection of the type of examination, are the subject of much discussion and debate. This article addresses some of the more controversial options and choices facing dental practitioners by reviewing the standard assessment techniques available to help make appropriate decisions, by summarizing and analyzing available data, and by offering recommendations for practice.

Efficiency↗
PubMed1987

Dental radiography: efficacy in the assessment of intraosseous lesions of the face and jaws in asymptomatic patients.

In this investigation the efficacy of dental radiography for the detection of occult intraosseous lesions of the face and jaws was evaluated. An analysis of 30 million health insurance records indicated that the period prevalence of malignant lesions was less than 5 cases/million/year, and for benign lesions approximately 100 cases/million/year. Data from a controlled observer-performance study showed that radiographic sensitivities ranged between 50% and 80%. The cost per true-positive finding was estimated to be +8.6 million per malignant case and +430,000 per benign case. An assessment of the dosimetric literature indicated that the benefits of radiographic screening as a means for early detection of a malignancy appear to be counterbalanced by the risk of causing a radiation-induced malignancy. Taken together, these data demonstrate that dental radiography is not efficacious for the purpose of detecting occult lesions.

Costs and Cost Analysis↗
PubMed1984

Comparison of biodistribution of 3H, 32P and 99mTc labeled Gpp(NH)p in tumor bearing hamsters.

Biodistribution and tumor uptake studies were carried out with intravenously injected tracer doses of Gpp(NH)p labeled with 3H, 32P or 99mTc . Syrian golden hamsters with cheek pouch carcinomas, induced by repeated topical applications of DMBA, were used as a tumor model. The biodistributions of these three radionuclides were different, indicating significant molecular cleavage of this nucleotide analog. It was also apparent that this compound labeled with 99mTc may not be useful for tumor imaging due to low tumor-to-blood specific activity ratio. The cheek pouch carcinoma tumor model may be valuable for the evaluation of tumor localizing radiopharmaceuticals.

9,10-Dimethyl-1,2-benzanthracene↗