PubMed · 4862817
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1966. [Oscilloscopes with memory].. https://pubmed.ncbi.nlm.nih.gov/4862817/
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This study investigated the effect of air inlet ring opening on the oscillatory pattern of the MM 1500 sonic handpiece and files. The oscillatory pattern of the driver head and files in air and under load was determined microscopically. The results showed that a critical opening of the air inlet ring was necessary to elicit oscillation of the driver head and sonic file. The driver oscillated in an elliptical manner, the displacement of which varied with air inlet ring opening. When operated in air the file exhibited an elliptical movement which was influenced by different design, length and thickness. This action was constrained under load and replaced by a longitudinal action of the same dimension for all files which appeared to have an efficient cutting action. This work shows that air inlet ring opening increases oscillation of the driver head once a critical opening has been reached and that clinical loading does not constrain the cutting action of the file.
This study was designed to measure the vibration of three X-ray tubes in simulated clinical conditions and the effect of this on image quality. Vibration was measured by exposing film to an X-ray beam collimated by a lead diaphragm with a pin-hole. Exposures were made of a test specimen with the X-ray tubes stationary and while oscillating after positioning by vertical, lateral and forward movements. The damping time for the X-ray tube to stop oscillating varied with the machine from 3 s to 102 s. The radiographic patterns caused by tube oscillation varied from closed loops to figure of eight movements with periodicities of between 0.5 and 1.0 s. Amplitudes of up to 5.9 mm were recorded; they were greater in a horizontal direction and affected by arm extension. Images of bone trabeculae and of small holes drilled in the proximal surfaces of two teeth were little affected by tube movement. Only under magnification was the definition of a ball-bearing seen to be slightly less distinct, with less than 1% variation in size. These effects are likely to be of little clinical significance.
The methods of oscillographic polarography and pulse differential polarography were used to test the release of some contaminating substances from polyvinylchloride (PVC) during autoclaving of water suspensions. The polarographic technique was able to detect in some extracts the presence of several contaminants, while the other PVC preparations did not release such substances. However the chemical nature of the contaminating substances has not been elucidated, the methods can serve as a screening method to detect heavy polymer contamination.