Research Summary abstract

British Dental Journal 200, 619 (2006)
Published online: 10 June 2006 | doi:10.1038/sj.bdj.4813647

Research summary: 
Tooth bleaching using a diode laser

C E Mercer1

  • Bleaching gels activated by Diode lasers in Power Bleaching act as effective insulators, helping prevent large increases in temperatures within the pulp chamber.
  • Teeth should never be directly irradiated with laser energy without the presence of the bleaching gel.
  • Temperature rises within the pulp chamber reduce to baseline levels very quickly after removal of laser irradiation.
  • Diode lasers used to activate bleaching gels are not considered dangerous to the vitality of dental pulps using power settings of up to 2W.


To measure the surface and pulp chamber temperature increases in vitro on upper and lower anterior teeth during a tooth whitening procedure using a diode laser.


A thermocouple was used to measure the temperature increase on the surface of an extracted upper central incisor tooth. Pulp chamber temperature readings were made on upper and lower central incisors, lateral incisors and canines. A diode laser recommended for tooth bleaching was tested at three different power settings (1W, 2W, 3W). Temperature measurements were made with and without the bleaching agent present on the labial tooth surface.


The increase in surface temperature readings ranged from 37°C (1W) to 86.3°C (3W) with no bleaching gel present. Pulp chamber temperature increases ranged from 4.3°C (1W) to 16°C (3W). The presence of the bleaching gel reduced temperature increases seen at the tooth surface and within the pulp.


The increase in the pulp chamber temperature with the laser used at 1-2W was below the critical temperature increase of 5.5°C thought to produce irreversible pulpal damage. However, a power setting of 3W produced a pulp chamber temperature increase above this threshold (16°C) and caution is advised when using this setting.

  1. Centre for Adult Oral Health, Queen Mary's School of Medicine and Dentistry

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