ABSTRACT
The sensitivity of the eye to the various wavelengths is highly different, showing the highest sensitivity to light in the 430- to 600-nm area. Modern high-speed handpieces are shown to have better properties in reducing the noise energy level than older ones. Regarding the noise emitted from high-speed handpieces, appropriate data are missing from the International Organization for Standardization standard. The manufacturers should give more information about the noise levels and frequencies at which their handpieces operate. More and more dentists, especially those working with bonding techniques in esthetic dentistry, are now exposed to “blue light hazards”. Although very few cases of possible eye damage caused by the dental light-curing units have been reported, many dentists are experiencing tiredness, “seeing spots on the walls”, and reduced night vision following extended bonding sessions. The human ear is exposed to various kinds of noise. Young adults may normally be able to hear frequencies from 20 to 20,000 Hz.
