Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ULTRASONICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 163 records · Page 9Linked to original sources
PubMed2006

The effect of pre-soaking and time in the ultrasonic cleaner on the cleanliness of sterilized endodontic files.

AIMS: To assess whether pre-soaking files in an enzymatic cleaner prior to ultrasonic cleaning had any effect on cleanliness and also to assess the effect of the time that endodontic files spend in an ultrasonic bath prior to sterilization on their overall cleanliness. METHODOLOGY: Twenty root canals in a total of ten patients were cleaned and shaped using conventional techniques. Following use, some of the files were pre-soaked and then ultrasonically cleaned for either 5, 10, 30 or 60 min. Other files had no pre-soaking and were then ultrasonically cleaned. There were two control groups, one where the files were pre-soaked and not ultrasonically cleaned and the other where the files were neither pre-soaked nor ultrasonically cleaned. All files were then subjected to a standard packing and autoclaving process. Following autoclaving, the files were examined using a light microscope at a magnification of 40x. The cutting section of each file was divided into two parts, the tip and the shaft, for visualization under the microscope. Any debris or cement on the files was scored using a modification of the scale used by Smith et al. (Journal of Hospital Infection, 51, 2002, 233). The data were analysed using one-way analysis of variance. RESULTS: Pre-soaking had no significant effect on the cleanliness of the files (P = 0.18 at the tip, P = 0.93 at the shaft). Ultrasonic cleaning had a significant effect on the cleanliness of the files (P < 0.00) but there was not a linear relationship between cleanliness and the ultrasonic cleaning time. There was little benefit in extending the ultrasonic cleaning time beyond 5 min. Calcium hydroxide deposits on two files were resistant to ultrasonic cleaning. CONCLUSIONS: There is no benefit in pre-soaking endodontic files prior to ultrasonic cleaning. The optimum time for ultrasonic cleaning was between 5 and 10 min. Further ultrasonic exposure, up to 60 min, did not improve cleanliness. Although a majority of files were free from debris following ultrasonic cleaning, a substantial minority still retained debris. This supports the case for endodontic files being single-use only.

Calcium Hydroxide↗
PubMed1991

Ultrasonic energy. Effects on vascular function and integrity.

BACKGROUND: Ultrasonic energy transmitted via flexible wire probes provides a new means of ablating atherosclerotic plaque. We studied the effects of ultrasonic energy (20 kHz) delivered via a ball-tipped wire probe on arterial vasomotor behavior in rabbit thoracic aortas in a perfused whole-vessel model. METHODS AND RESULTS: After precontraction with phenylephrine (10(-5) M) or KCl (60 mM), the effects of ultrasonic energy (0.7-5.5 W x 60 seconds, 42-330 J) on arterial vasomotor behavior were measured using long-axis ultrasonic vessel imaging of the proximal (ultrasonic probe-treated) and distal (untreated) control segments. The efficacy of plaque ablation at these same probe-tip power outputs was evaluated in atherosclerotic, human cadaver iliofemoral arteries. Ultrasonic energy caused dose (energy)-dependent relaxation in rabbit aortas after precontraction with phenylephrine in arteries with endothelium (n = 8) and without endothelium (n = 8) (p less than 0.001 versus ultrasound treated at power outputs of 2.9 and 5.5 W). There was no difference in the relaxation dose responses between endothelialized and endothelially denuded segments (p = NS). Ultrasonic energy also caused significant relaxation (67 +/- 8%) after voltage-dependent precontraction with 60 mM KCl. Temperature measurements revealed less than 1 degrees C warming of the vessel wall during as long as 2 minutes of treatment at a power output of 5.5 W. Pathological examination showed no smooth muscle injury at (moderate) power outputs that caused arterial relaxation. At probe-tip power outputs of 2.9-5.5 W, ultrasonic energy recanalized two of two totally occluded cadaveric iliofemoral vessel segments. The ultrasonic ablation catheter was also demonstrated to cause arterial relaxation in a recanalized canine femoral artery in vivo. CONCLUSIONS: Ultrasonic energy delivered via a flexible-wire probe produces dose-dependent, endothelium-independent smooth muscle relaxation capable of reversing both receptor-mediated and voltage-dependent vasoconstriction in vitro. At moderate power outputs, this relaxation response does not appear to be due to thermal effects or irreversible smooth muscle cell injury. This vasorelaxant effect of ultrasonic energy is also apparent in vivo, at doses that effectively ablate atherosclerotic plaque, and may improve the safety of arterial recanalization using ultrasonic energy.

Animals↗