PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “MICRORADIOGRAPHY”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1992

[Microradiography in the study of trabecular parameters].

The intermethod variation in measurement of trabecular bone volume (VTO) and the indirect estimation of its microstructure according to Parfitt MTPT (microns), MTPD (/mm) and MTPS (microns) were evaluated in seven undecalcified bone biopsies by analyzing the microradiograph of a 100-microns-thick section with an automatic method (IBAS II Zeiss, Munich) in addition to reference methods (manual and semiautomatic) described in the literature and performed on 7-microns-thick stained sections. Three consecutive 7-microns-stained sections and one 100-mu-thick microradiographed section were taken in each specimen. The 100 microns-thick section was also superficially stained. Trabecular bone volume was measured with both a manual integrating eyepiece and an automatic method. The automatic method on the microradiograph underestimated the VTO by 24.42%. There was a correlation (r = 0.75; p < 0.02) between the manual and computerized methods. Mean trabecular plate thickness (microns), mean trabecular plate density (/mm) and mean trabecular separation (microns) were measured with both semiautomatic and automatic methods. The automatic method on the microradiograph underestimated the MTPT (microns) by 18.98% and the MTPD (/mm) by 14.14% and overestimated the MTPS (microns) by 23.17%. For the MTPT (microns) there was a correlation (r = 0.88; p < 0.02), between both methods, and the correlation was good for MTPD (/mm) (r = 0.97; p < 0.001), and MTPS (r = 0.86; p < 0.002).

Biometry↗
PubMed1990

[Stratification of the experimental incipient caries (polarized light microscopy and microradiography)].

The enamel caries establishes when at least a part of enamel dissolves by the action of cariogenic bacteria which produce insoluble glucan and lactic acid. The experimental caries should be prepared at the condition which simulates the natural environment. The author made 1 mm thick sections from 29 teeth extracted for convenience of orthodontic reason. The surface was covered except the "window" which will be exposed to the acid milieu. The samples were immersed for 4 to 120 days in the gelatin added lactate buffer of pH 4.5, pH 5.0, and pH 5.5. Ground sections were made after the experiment. The structure of the experimental incipient caries was described after Darling (1963); surface layer, body of the lesion, dark zone, and translucent zone. When the section was immersed for shorter period in the buffer of pH 4.5, the lesion was made up only two layers, namely, the surface layer and the body of the lesion. This type of lesion will be called Type I, hereafter. When the action of acid was more intense, only one layer, the body of the lesion remained after the dissolution of the surface layer. This type of lesion will be called Type II. The lesion which provided with all 4 layers will be called as Type III, and the lesion which was made up of 3 layers which remained after dissolved surface layer, will be called as Type IV. Both Type III and Type IV were established after immersing for longer period in pH 5.5, although they could be observed in groups which immersed in lower pH. Of the samples examined, a few example showed a five-layered structure; the surface layer, the first body of lesion, the first dark zone, the second body of lesion, the second dark zone, and the translucent zone. This phenomenon suggests that the speed of caries development was not uniform throughout the experiment. The relationship between the depth of the lesion, and the pH and the duration of acid action was studied. In the pH 5.0 group, the development of caries lesion was temporarily arrested between 30 and 60 days. This phenomenon would be an explanation to the formation of five-layered lesion.

Dental Caries↗
PubMed1986

[Approach to age determination based on dental morphological criteria obtained in microradiography, stereomicroscopy and scanning electron microscopy].

The determination of the age owing to the morphology of permanent teeth has been done in 14 men and women, using criteria proposed by Gustafson. It was faithful, the difference between age determined by this method and the true age of these patients being never superior to 3 years. The application of scanning electron microscopy allows to improve some of the criteria used for this determination, especially that based upon the dentinal senescence.

Adult↗
PubMedDate not supplied

Microradiography: a theoretical basis and practical applications.

If low magnification (less than 40x) is required of either thick soft tissue specimens (greater than 20 mm) containing contrast media filled structures or dense tissue, such as bone (greater than 5 mm), a diagnostic, radiographic tube and a 50 kVp setting would prove satisfactory. In this situation Kodak Type R film would provide the required resolution. When the same image enlargement is desired but the soft tissue (greater than 20 mm) does not contain contrast media or the dense tissue is thinner (0.5-5 mm), a specialized radiographic tube is necessary. The unit must be capable of generating a range of 30-40 kVp. Most mammography equipment will produce the necessary kilovoltage if neither a Faxitron nor the resources to build a unit are available. Once again the Kodak Type R or a similar industrial radiographic film would be the film of choice. When high magnification (greater than 40x) is required, indicating thin low density (10-20 mm) or high density (less than 0.5 mm) tissues are being examined, a specialized tube capable of producing 20 kVp is necessary. Kodak High Resolution glass plates or polyester-based film must be used to record the image. Due to grain size visible at high magnifications, both the Kodak Type R radiographic films and the Agfa photographic films proved unsuitable.

Animals↗