Biomedical subjects

E Sorainen

Publications and source records attributed to E Sorainen.

6 recordsLinked to original sources

PubMed2002

Noise level and ultrasound spectra during burring.

The aim of this study was to evaluate the noise spectra of current dentistry equipment during normal work at the dental clinic and in the laboratory. In the study, noise was measured during the dental treatment of seven patients at a dental clinic and also in the acoustics laboratory, where working noise was simulated by drilling a polyacetal plate. All samples were analyzed in audible and ultrasonic areas in the one-third octave bands of 20-80,000 Hz. The measuring instruments used were B&K 4135 microphones, B&K 2633 preamplifiers, the B&K 2811 multiplexer, and the B&K 2133 real-time analyzer with the ZT 0318 high-frequency expansion unit. In the in situ measurements, the A-weighted sound pressure level was occasionally over 85 dB(A), and the equivalent continuous A-weighted sound pressure level, L(Aeq), was 76 dB(A). The noise level was most powerful in the one-third octave band of 40,000 Hz, where it was 74 dB. In laboratory measurements, the noise levels of the air-turbine and the micromotor hand pieces (n=16) were also most powerful in the one-third octave band of 40,000 Hz, where they were 80-89 dB. The L(Aeq) of the different micromotor handpieces (n=6) varied between 76 dB(A) and 77 dB(A), and the L(Aeq) of the turbine hand pieces (n=10) varied between 77 dB(A) and 82 dB(A). The noise of the drills is most powerful in the high frequencies, so using hearing protectors, it is possible that speech communication improves because the protectors attenuate high frequencies more than low frequencies. The very light protectors give sufficient protection against the drilling noise.

Acoustics↗

PubMed1998

Whole-body vibration of tractor drivers during harrowing.

The seat vibration of nine tractors was investigated while drivers harrowed fields in eastern Finland. The vibration acceleration of the tractor driver's seat was measured simultaneously along three mutually perpendicular axes. The triaxial seat-accelerometer was used for the measurements. The vibration signals were amplified with charge amplifiers and recorded with an FM tape recorder. The samples were analyzed with a real-time analyzer. In all cases, the average vibration of the seat exceeded the 8-hour "fatigue-decreased proficiency boundary" specified in the international standard ISO 2631/1. The instantaneous accelerations of the most harmful one-third octave band of vibration were sometimes two- to threefold compared with the average.

Agricultural Workers' Diseases↗

PubMed1988

Vibration in textile mills.

The vibration in nine halls of the six weaving mills was measured in 1978-80. The measurements were taken at regular intervals in the working area of the weavers, which was the wooden support attached to the machine or the floor of the textile mill. The accelerometer was mounted with screws onto the working area, and all vibration samples were analyzed immediately, in situ. The vibration of the floor was tangent to or exceeded slightly the "reduced comfort boundary" specified in International Standard ISO 2631/1 (1985) only in the areas where the floor was not against the ground. The greatest amount of vibration occurred on the supports which had been attached to the machines. On these supports the vibration in places exceeded the "fatigue-decreased proficiency boundary."

Finland↗

PubMedDate not supplied

Whole-body vibration of locomotive engineers.

Vibration of the seat and the body of a diesel locomotive and an electric locomotive were measured while driving on the railways of Eastern Finland. At the speed of 120 km/h for the diesel locomotive and 140 km/h for the electric locomotive (the greatest permissible speeds) the vibration of the seat was tangent to the "fatigue-decreased proficiency boundary" of the international standard ISO 2631/1(1) in the side-to-side direction in one-third octave bands of 1-1.6 Hz. The frequency response measurements between the body of the locomotive and the seat indicated that the seat did not reduce side-to-side vibration of the body at low frequencies where the vibration was most harmful.

Finland↗

PubMedDate not supplied

Vibration of dental handpieces.

The vibration of new (n=4) and used (n=16) dental handpieces was tested in three directions during idling. In addition, work was simulated by drilling on plastic plate with all new and five used handpieces. The weighted vibration according to standard ISO 5349:1986 and the total acceleration of high-frequency vibration ("ultravibration") in the frequency range of 1.43-11.06 kHz were analyzed. Neither the water and air injection nor the grip force of fingers had any significant effect on the vibration level. The work simulation did increase the vibration of the handpieces, and the vibration became more broadband. The weighted accelerations were plainly below the hazardous acceleration determined in ISO 5349 and the ACGIH-TLV. The vibration spectra of the handpieces contained powerful vibration at high frequencies, but the effects of this ultravibration and exposure during work are not well known.

Dental High-Speed Equipment↗

PubMedDate not supplied

High-frequency noise in dentistry.

Earlier studies have revealed that dentists have higher hearing thresholds than expected. The aim of this study was to evaluate the noise levels of current dentistry equipment under very controlled conditions. This noise study was carried out in the Acoustics Laboratory of Kuopio Regional Institute of Occupational Health, the background noise of which is about 0 dB(A). Working noise was simulated by drilling a polyacetal plate. During drilling and idling, the noise of the hand pieces was measured over a reflecting plane on the hemisphere surface, the radius of which was 0.3 m, and 10 noise samples were picked for each hand piece. The average sound pressure level and the sound power level of the devices were calculated applying the standard ISO 3744. The measurement and analysis were done in the one-third octave bands of 25-80,000 Hz. The measuring instruments used were the B&K 4135 microphones, the B&K 2633 preamplifiers, the B&K 2811 multiplexer, and the B&K 2133 real-time analyzer with the ZT 0318 high-frequency expansion unit. During the simulated work, the average A-weighted sound pressure level of the new and old hand pieces was 76-82 dB(A), that of the power suction tube 77 dB(A), the saliva suction tube 75 dB(A), and the ultrasonic scaler 83 dB(A). The average ultrasound level of the ultrasonic scaler was 107 dB at the one-third octave band of 25,000 Hz.

Dental Equipment↗