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

Abstract

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.

The effect of light-activation sources on tooth bleaching

“…However, some researchers have stated that no acceleration or increase in efficacy occurs when using light sources 353642. Light-activated whitening systems add cost, occupy operatory space, can cause burning of the soft tissue, and can increase operatory temperature 2.…”

“…Where, approximately 35% HP was used with different light sources (LED/diode laser, a halogen lamp, plasma arc lamp, argon laser). Bruzell et al ., 200942 reported no difference in efficacy between teeth bleached with or without irradiation for any of the products. The inspection of teeth was performed one week after bleaching using seven bleaching products with or without simultaneous use of seven different bleaching lamps.…”

Temperature rises during tooth bleaching with different light-curing units

“…[42] Dominguez et al [10] used SEM to examine enamel that was bleached using different light-curing units. They found no significant damage to the enamel.…”

UV‐C‐irradiation sublethal stress does not alter antibiotic susceptibility of the viridans group streptococci to β‐lactam, macrolide, and fluoroquinolone antibiotic agents

“…In addition, the use of bleaching lamps in cosmetic teeth whitening is becoming more popular. The wavelength of light emitted from such sources is variable; however, in one study, a bleaching lamp exceeded t max values for UV exposure 8 …”