Digital subtraction temporomandibular joint tomography.

Receiver operating characteristics analysis was performed to demonstrate differences in diagnostic performance among conventional tomograms, digitized tomograms, and subtraction tomograms. Digital subtraction tomography was found to be the best imaging modality for detecting artificially created lesions in the two selected temporomandibular joint locations. There was a statistically significant difference in diagnostic performance between conventional tomograms and subtraction tomograms for the detection of temporomandibular joint bony lesions. There was also a statistically significant difference in diagnostic performance between digitized tomograms and subtraction tomograms in the detection of these bony lesions. There was no statistically significant difference in diagnostic performance between conventional tomograms and digitized tomograms for the detection of temporomandibular joint bony lesions. The significance level was set at p = 0.05. Results of the analyses of variance showed that with digital subtraction tomograms, observer reliabilities were higher than with conventional and digitized tomograms.

The posterior wall of the maxillary sinus as seen in panoramic radiography.

The dental and sinus projection programs of the PM 2002cc panoramic x-ray unit were compared with regard to the visualization of the maxillary sinus posterior wall of a dried skull. The posterior wall of the maxillary sinus appeared different on each program. In the sinus projection program the posterior wall appeared narrower than that in the dental projection program. The main cause for the difference of the maxillary sinus posterior wall image was the projection angle. In the sinus projection x-rays entered more tangentially to the posterior wall of the sinus than in the dental projection, but in the dental projection x-rays entered more tangentially to the mediosuperior and medioinferior region of the maxillary sinus posterior wall. Thus a large, widely destructive lesion in the posterior wall of the maxillary sinus would be more easily detected with the sinus projection. On the other hand, lesions confined to the mediosuperior and medioinferior regions of the posterior wall will be depicted more clearly with the dental projection program.

Comparison of x-radiation doses between conventional and rare earth panoramic radiographic techniques.

The radiation dose to radiobiologically critical organs at various anatomic sites in a phantom was compared with the use of rare earth screen/film combinations and calcium tungstate screen/film combinations. Rare earth screens and films produced a reduction in dose up to 40% to 50% depending on the anatomic site.

Radiobiologic risk estimation from dental radiology. Part II. Cancer incidence and fatality.

With the use of the measured absorbed doses from part I of this article, the specific radiobiologic risk to the patient from (1) five different panoramic machines with rare-earth screens, (2) a 20-film complete-mouth survey with E-speed film, long round cone, (3) a 20-film complete-mouth survey with E-speed film, long rectangular cone, (4) a 4-film interproximal survey with E-speed film, long round cone, and (5) a 4-film interproximal survey with E-speed film, long rectangular cone, was calculated. The estimated risks are expressed in two ways: the probability of radiation-induced cancer in specific organs per million examinations and the probability of expression of a fatal cancer per million examinations. The highest risks calculated were from the complete-mouth survey with the use of round collimation. The lowest risks calculated were from panoramic radiography and four interproximal radiographs with rectangular collimation.

Radiobiologic risk estimation from dental radiology. Part II: cancer incidence and fatality / Estimativa do risco radiológico em radiologia dentária. Parte II. Incidência de câncer e fatalidade (morbidade)

With the use of the measured absorbed doses from part I of this article, the specific radiobiologic risk to the patient from (1) five different panoramic machines with rare-earth screens, (2) a 20-film complete-mouth survey with E-speed film, long round cone, (3) a 20-film complete-mouth survey with E-speed film, long rectangular cone, (4) a 4-film interproximal survey with E-speed film, long round cone, and (5) a 4-film interproximal survey with E-speed film, long rectangular cone, was calculated. The estimated risks are expressed in two ways: the probability of radiation-induced cancer in specific organs per million examinations and the probability of expression of a fatal cancer per million examinations. The highest risks calculated were from the complete-mouth survey with the use of round collimation. The lowest risks calculated were from panoramic radiography and four interproximal radiographs with rectangular collimation

Radiobiologic risk estimation from dental radiology. Part I. Absorbed doses to critical organs.

The aim of the present study was to generate one consistent set of data for evaluating and comparing radiobiologic risks from different dental radiographic techniques. To accomplish this goal, absorbed doses were measured in fourteen anatomic sites from (1) five different panoramic machines with the use of rare-earth screens, (2) a twenty-film complete-mouth survey with E-speed film, long round cone, (3) a twenty-film complete-mouth survey with E-speed film, long rectangular cone, (4) a four-film interproximal survey with E-speed film, long round cone, and (5) a four-film interproximal survey with E-speed film, long rectangular cone. The dose to the thyroid gland, the active bone marrow, the brain, and the salivary glands was evaluated by means of exposure of a tissue-equivalent phantom, fitted with lithium fluoride thermoluminescent dosimeters (TLDs) at the relevant locations.

Variations in film exposure, effective kVp, and HVL among thirty-five dental x-ray units.

Speed group "E" dental films were exposed in thirty-five dental x-ray units and processed under rigidly controlled conditions. The exposure, in milliroentgens required to produce an overall film density between 0.85 and 1.05 density units at the 9 mm. step of an aluminum step-wedge, ranged from 94 to 186 mR. The wide range in normalized exposure required to produce a standard density of 1.0 was associated with half-value layer and effective operating kilovoltage in only a general way. The half-value layer of thirty-five dental x-ray units ranged from 1.9 to 2.9 mm. Al, and their effective operating kilovoltages ranged from 62 to 77 kVp when units were set at 70 kVp. The exposure required to produce a specific radiographic density depended largely on the individual characteristics of the x-ray unit used.

Panoramic radiographic survey of dentists participating in ADA health screening programs: 1976, 1977, and 1978.

Results of the panoramic examination of dentists participating in the health evaluation program of the ADA annual sessions held at Las Vegas (1976), Miami Beach (1977), and Anaheim (1978) were reported and compared as accurately as possible with the results of the panoramic examinations of dentists taking part in the health evaluation programs of the ADA annual sessions in 1964, 1966, and 1968. The panoramic radiograph continues to serve as a diagnostic aid in dental health evaluation programs. Only general impressions may be drawn from surveys of this nature for various reasons: the inability to follow up each case with a clinical examination; the lack of correlation of findings between examiners; and the use of different criteria each year. Generally, dentists examined in the health evaluation programs in 1976, 1977, and 1978 were in good dental health.

Cytochemical correlates of structural sexual dimorphism in glandular tissues of the mouse.

Circulating androgens are known to effect a sexual dimorphism of the submandibular gland and kidney of the mouse. Enzyme histocytochemical differences that correlate with these structural changes have been the subject of much study, especially in the kidney. In the present study, emphasis was placed on the hypogonadic effects of diabetes mellitus on the submandibular gland and kidney of C57Bl/KsJ db/db inbred mice with an autosomal recessive disease resembling maturity onset human diabetes mellitus. These glands of adult diabetic mice of both sexes were compared with those of unafflicted heterozygous littermates. The mitochondrial cytochrome oxidase and peroxisomal and cytoplasmic catalase were studied in their submandibular glands and kidneys. The parasympathetic innervation of the submandibular glands was studied by a histochemical method for acetylcholinesterase. The extensive differentiation of striated ducts of the submandibular gland into granular tubules in the postpubertal male mouse was readily evident with the cytochrome oxidase procedure. This differentiation resulted in ductal staining patterns characteristic of the sexes. Alteration of these patterns suggested that demasculinization or feminization was occuring in the male diabetic mice and that masculinization or virilization (defeminization) was occurring in the female diabetics. Similarly, in kidney, study of the parietal epithelium of Bowman's capsule revealed feminization in the male diabetics and masculinization in the female diabetics. With the catalase procedure, a dramatic sexual dimorphism was observed in the kidneys of the heterozygous unafflicted mice. Peroxisomal staining of epithelial cells of the proximal convoluted tubules was much more intense in the outer medulla of the male than of the female. In kidneys of the diabetics, the staining patterns again suggested that feminization of the male and masculinization of the female kidneys had occurred. On the other hand, neither a sexual dichotomy nor effects due to diabetes could be observed in the characteristic catalase staining observed in the luminal epithelial cells of submandibular gland distal ducts. The parasympathetic innervation of the submandibular gland, as revealed by the acetylcholinesterase method, was also markedly sexually dimorphic in the unafflicted mice. This was due to the more extensive innervation of the larger granular ducts characteristic of male than of the smaller striated ducts of the female. As a result of diabetes, the innervation and duct size decreased in the submandibular gland of the male, suggesting feminization, whereas they increased in the female suggesting masculinization. These changes were consistent with those observed in sumandibular gland with the cytochrome oxidase procedure. Attempts were made to interrelate all of the enzyme histochemical changes observed in submandibular gland and kidney with the weights of these glands, sex, gonadal weights, diabetic status and urinary protein excretion...

A three-year survey of viral hepatitis in West London.

During a total population survey of viral hepatitis in the London Boroughs of Hounslow, Richmond and Ealing, 784 patients were seen in three years from 1 March 1972 to 28 February 1975. A diagnosis of viral hepatitis was accepted in 489. The annual incidence was 24 per 100 000. 455 of the patients were tested for the hepatitis B surface antigen (HBsAg) by a radioimmunoassay technique and 93 (20%) of these were positive. The majority of the patients with type B hepatitis were in their third or fourth decades. None was under the age of 16. The male to female ratio among patients with hepatitis B was 2 to 1 in those under the age of 30 and 5 to 1 in those aged 30 and over. The seasonal distribution of viral hepatitis showed a peak in the spring, solely from an increased incidence of non-B hepatitis, and a second, smaller peak in the autumn. There was no appreciable clustering of patients except for one local outbreak in a housing estate during the first year affecting mainly children going to the same primary school, and their parents. Patients with hepatitis B had a longer pre-icteric illness (p less than 0.05), greater duration of jaundice (p less than 0.001) and higher peak levels of serum bilirubin (p less than 0.0005) and serum alanine amino transferase (A1T) (p less than 0.03) than patients with non-B hepatitis. The finding of the surface antigen was also associated with a higher frequency of skin rash (p less than 0.0005) and a greater duration of arthralgia (p less than 0.03). Among the HBsAg negative patients the incidence of arthralgia increased with age (p less than 0.0005). Abdominal pain (p less than 0.005) and vomiting (p less than 0.005) were more common in the young. The injection experience of patients with hepatitis B showed a high proportion of 'non-therapeutic' exposure such as drug addiction. Significantly more HBsAg positive men were single than in the local community (p less than 0.001) or among the HBsAg negative men (p less than 0.01). There was no significant difference between the proportions of single women among the antigen positive and negative patients. Many of the HBsAg positive single men were either known to be or strongly suspected of being homosexual. The ad subtype of the HBsAg was found more often in males (p less than 0.01), particularly over the age of 30. All eight drug addicts tested for subtype were ay, as were two non-addicted female consorts. The association between addiction and ay subtype was highly significant in the males (p less than 0.001). The ad subtype was found in all 11 of the admitted homosexual HBsAg positive men and in all but one of the 17 strongly suspected of being homosexual.

Catalase in salivary gland striated and excretory duct cells. I. The distribution of cytoplasmic and particulate catalase and the presence of catalase-positive rods.

Catalase-positive rods of different dimensions, which frequently appeared crystalline by light microscopy, were found to be concentrated along with microbodies and cytoplasmic enzyme in the cells of the striated and extralobular excretory ducts of mouse salivary glands. When an entire mouse submandibular gland and its ducts were excised, fixed, sectioned and incubated for catalase demonstration, the excretory ducts were intensely stained relative to the remainder of the gland. Light microscopic examination of the stained ductal cells revealed particulate catalase in the form of rods and microbodies as well as reactivity due to non-particulate cytoplasmic enzyme. The cytoplasmic enzyme activity was less intense in some ductal epithelial cells (light cells) which were interspersed in mosaic arrangement among those more intensely stained (dark cells). The rods were somewhat more common in the light cells. Although the rods lack a symmetrical definitive crystal habit, their gross conformation and periodic substructure are reminiscent of crystalline catalase. No rods and relatively few peroxisomes were observed in excretory duct cells of germ-free mice although cytoplasmic catalase was abundant. These observations suggest that the catalase in salivary gland duct cells could be related in some way to the protection of the gland or the oral cavity or both against micro-organisms. Alternatively, the enzyme could be involved in the non-thyroidal biosynthesis of iodinated tyrosine derivatives.

Cytochemical correlates of structural sexual dimorphism in glandular tissues of the mouse. I. Studies of the renal glomerular capsule.

The parietal epithelium of Bowman's capsule has been analyzed by enzyme cytochemistry in kidneys of mice (C57BL/6J) from birth to 50 days of age. There is a greater tendency for cells in the central portions of the capsular crescent to be cuboidal in post-pubertal males than in pre-pubertal mice of either sex or in post-pubertal females where they are generally squamous; moreover, these heightened capsular cells have a distinct microvillous border. Cytochemical procedures were selected which might confirm the morphological suggestion that the cuboidal parietal epithelium possesses an absorptive capacity. The oxidoreductase activity of the mitochondria of the cuboidal cells of this layer is comparable to that of the columnar cells of the proximal convoluted tubule. The cytochrome oxidase activity of the mitochondria in both of these segments of the nephron is intense. This is in sharp contrast to the unreactive mitochondria in the squamous cells of the parietal epithelium. Furthermore, a striking heterogeneity in the degree of cytochrome oxidase activity is evident in the mitochondria of the cuboidal parietal cells as well as in the cells of the proximal tubules. In the former cells, active mitochondria were generally found near microvilli at the apical ends and in the areas of the basal infoldings whereas those in a central position were more frequently unreactive. The brush border of the cuboidal capsular epithelium had prominent alkaline phosphatase and aminopeptidase activities as has previously been observed in other brush borders. Functional capacity corresponding to the morphological and cytochemical specialization of the cuboidal capsular cells was demonstrated by their uptake of horseradish peroxidase. This exogenous protein tracer could be seen in apical vacuoles and phagosomes in the cuboidal parietal epithelium. The cytochemical resemblance of the cells of this epithelium to those of the proximal convoluted tubules suggests a similar involvement in resorption and perhaps in active transport. A possible relationship of this differentiation of the capsular epithelium to the proteinuria normal for adult male mice is discussed.