UVB and UVA irradiances from indoor tanning devices.

Indoor tanning is common in spite of its classification as carcinogenic. Too high an ultraviolet (UV) irradiance and a lack of compliance with regulations have been reported. We measured UV irradiance from a large number of Norwegian solariums (sunbeds and stand-up cabinets) currently in use. Compliance (solariums and facilities) with national regulations and the effect of inspections delegated to local authorities (since 2004) were also studied. In 2008, 78 tanning facilities were selected from six regions throughout Norway that contained municipalities with and without local inspections. UV irradiance was measured with a CCD spectroradiometer in 194 out of 410 inspected solariums. Mean erythema weighted short (280-320 nm) and long (320-400 nm) wave UV irradiances were 0.194 (95% confidence interval (CI) 0.184-0.205) and 0.156 (95% CI 0.148-0.164) W m(-2), respectively. Only 23% of the solariums were below the UV type 3 limit (<0.15 W m(-2), short and long wave). Irradiances varied between solariums: spectral UVB (280-315 nm) and UVA (315-400 nm) irradiances were 0.5-3.7 and 3-26 times, respectively, higher than from Oslo summer sun. In total, 89.9% of the tanning facilities were unattended. Overall compliance increased since the first study in 1998-1999, but total UV irradiance did not decrease, mainly because of higher UVA irradiance in 2008. Solariums have become even less similar to natural sun due to higher UVA irradiance. Local inspections gave better compliance with regulations, but irradiances were significantly higher in municipalities with inspections (p ≤ 0.001, compared to without). Unpredictable UV irradiance combined with insufficient customer guidance may give a high risk of negative health effects from solarium use.

In vitro efficacy and risk for adverse effects of light-assisted tooth bleaching.

The use of optical radiation in the so-called light-assisted tooth bleaching procedures has been suggested to enhance the oxidizing effect of the bleaching agent, hydrogen peroxide. Documentation is scarce on the potential adverse effects of bleaching products and on optical exposure risks to eyes and skin. The efficacy of seven bleaching products with or without simultaneous use of seven different bleaching lamps was investigated using extracted human teeth. The bleaching effect was determined immediately after treatment and one week later. Tooth surfaces were examined for adverse alterations after bleaching using a scanning electron microscope. Source characteristics of eight lamps intended for tooth bleaching were determined. International guidelines on optical radiation were used to assess eye and skin exposure hazards due to UV and visible light emission from the lamps. Inspection of teeth one week after bleaching showed no difference in efficacy between teeth bleached with or without irradiation for any of the products. Scratches, probably from the cleaning procedure were frequently seen on bleached enamel irrespective of irradiation. Maximum permissible exposure time (t(max)) and threshold limit values were exceeded for about half the bleaching lamps investigated. One lamp exceeded t(max) even for reflected blue light within the treatment time. This lamp also exceeded t(max) values for UV exposure. The lamps were classified as "low risk" and as borderline to "moderate risk" according to a relevant lamp standard.

Evaluation of eye protection filters for use with dental curing and bleaching lamps.

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.