Evaluation of Eye Protection Filters for Use with Dental Curing and Bleaching Lamps

Abstract

Exposure to intense radiation sources in a dental clinic necessitates the use of eye protective filters to avoid blue-light photochemical retinal hazard. We have investigated the filtering quality and assessed whether the filters protect sufficiently against retinal hazards throughout the workday. Visible light transmittance of 18 protective filters was measured. These products consisted of spectacles, stationary lamp shields, and a hand-held shield intended for use in dental clinics. Nine of the 18 tested filters had adequate filtering capacity according to today's lamp technology and exposure limit values. These filters transmitted less than 0.1% of the radiation at any wavelength between 400 nm and 525 nm. Seven of the nine filters showed transmission values below the detection limit (approximately 10(-3)%) in the wavelength band between 400 nm and 500 nm. Filters of inferior quality may prove inadequate if the use and radiation intensity of the lamps further increase. Lack of protection may also occur if a filter is used to protect against emission from a lamp with properties other than the lamp for which the filter has been intended. It is of major importance that the spectacles/shields accommodate the emission from the lamp source. The suppliers of dental radiation sources should be responsible for information on the need for and proper use of eye protectors. In addition, the filters should be marked according to testing procedures appropriate for the specific use.

Occupation and cancer – follow-up of 15 million people in five Nordic countries

“…Dentists are exposed through their daily work to lamps that emit no UV-B, and the levels of UV-A are so low that they are not considered to add to the risk [128].…”

Contemporary Issues in Light Curing

“…122,123 Some blue light filtering glasses ('orange blue-blockers') have been shown to reduce the transmission of light below 500 nm to less than 1%. 125,130,131 When blue light filtering glasses are used, instead of looking away from the bright blue light from the LCU, the operator can safely watch what they are doing when light curing. This will improve the amount of light delivered to the restoration.…”

Evaluation of Eye Protection Filters Used with Broad-Spectrum and Conventional LED Curing Lights

“…Some new LED LCUs have multiple emission peaks that may include UV light and some of the filters evaluated in this study were not able to block the UV light component as well as other filters. This lack of protection may cause ocular damage (6,12) and clinicians should use the correct protective filter especially if they use a broad-band LED curing light. The maximum blue-light exposure of 1 min/day has been recommended to avoid retinal damage (2).…”

“…This broader range can improve the degree of conversion of the new resin based composites that include the aforementioned alternative photoinitiators (9,10,11). The ability of protective filters to block the damaging light from contemporary light curing units (LCU) continues to be unclear (12).…”