KSPM
Search
- Page Path
- HOME > Search
Original Articles
- Temporary Threshold Shift of Vibration Sensation by Dental Handpiece.
- Seong Ah Kim, Jong Young Lee, Doohie Kim, Soon Woo Park
- Korean J Prev Med. 1995;28(4):765-772.
- 1,976 View
- 24 Download
-
Abstract
PDF - This study was performed to investigate the possibility of temporary threshold shift (TTS) of vibration sense could induced by exposure to high-frequency vibration or by work position taking by dentists in drilling or polishing. The vibratory perception thresholds (VPT) of 28 healthy men were measured on the index fingertip pulp of dominant hand at 250Hz. The vibrating tool used in test was a low-speed handpiece of 34,000 rpm. For the TTS test, the dominant hand was exposed to high-frequency vibration and to work position for five minutes, respectively. The VPTs before and after vibratory exposure were 23.5+/-3.5 dB, 30.8+/-4.2 dB, respectively and VPT after work position was 23.7+/-4.6 dB. The difference between before and after vibartory exposure was statistically significant (P<0.001). The correlation of height, weight and BMl with baseline VPTs was not statistically significant. Also, there was no difference of VPTs by smoking. These results suggest that high-frequency vibration from dental handpieces might cause the impairment of vibration sensation.
-
Summary
- Combined Effect of Vibration Intensity, Grip Temperature, Noise and Pushing Power on Grip Forces and Skin Temperatures of Fingers.
- Kyungsim Koh, B Griefahn, M Fritz, P Brode
- Korean J Prev Med. 1994;27(4):763-776.
- 2,030 View
- 21 Download
-
Abstract
PDF
- Recent studies reveal that grip forces during the hand-arm vibration are most significant for the genesis of vibration-induced white finger syndrome. Therefore, exerted grip forces and skin temperatures or fingers were regarded as dependent variables in experiments and the effects of grip temperature, noise, pushing force, vibration and the combined effect of vibration and pushing force were studied. The objectives or the present study were, first, to varify and compare the changes of grip force affected by grip temperature, noise, pushing force, vibration and the combined effect of vibration and pushing force and, second, to observe the reaction of finger skin temperature affected by above factors. Forty-six healthy male students(25.07+/-2.85) participated in five systematically permuted trials, which endured 4 minutes each other. Experiments were executed in a special chamber with an air temperature of 21 C. In each experiments, the subjects were exposed to five experiment types: (l) grip force of 25 N only, (2) pushing force of 50 N, (3) acceleration of vibration 7.1m/sec2(z-direction), (4) pink noise or 95 dB(A) and (5) combination of pushing force 50 N and acceleration of vibration 7.1m/sec2. A repeated-measures analysis of variance(ANOVA) was performed on the grip force to test whether it was affected by noise, pushing force, vibration and pushing force. The present results show that vibration was significantly related to the increase of grip force, but the other factors, such as pushing force, noise and grip temperature had no significant influence on the increase of grip force and that the reaction of finger skin temperature were significantly affected by the skin temperature at start of experiment and grip temperature, not grip force and other experimental conditions. Therefore, we suggest that the management for decreasing the grip force is meaningful to prevent the occurrence of Hand-arm vibration syndrome (HAVS).
-
Summary
First
Prev
