As a treatment for pain, inflammation and wound healing, low-power laser irradiation has already become a common practice in the dental field. There have been many reports on the efficiency of the low-power laser irradiation, especially, as a treatment for pain accompanied by hypersensitive dentin. However, in these experiments, low-power laser irradiation was only used once, on areas of around the root apex or hypersensitive area.
To evaluate the effect of low-power laser irradiation on hypersensitive dentin, this study was carried out the following experiment on aspects of analgesic effect according to the diffe rent irradiated areas, such as the hypersensitive area, the around the root apex and the nerve foramen either the mental or infraorbital foramen. Semi-conductive laser (Diotron, Osada K.K) laser energy 30mW, wavelength 830nm, wave sourse: Ga-Al-As and He-Ne laser (Soft Laser 632, World Wide Laser ind.) laser energy 6mW, wavelength 632.8nm, wave source: He-Ne were provided as experimental apparatus and irradiated 5 minutes. Assessment criteria was classified the strength of pain as: no pain, mild pain, strong but tolerable pain and intolerable pain before the laser irradiation. After irradiation, evaluated the pain as: extremery effective (reduced pain considerably), effective (less pain), no change and worse (increased pain).
Consequently results were obtained as follows:
1. Using Semi-Conductive laser and He-Ne laser, the analgesic effect was most effective on hypersensitive area, next comes around the root apex and followed by the nerve foramen.
2. The cross-over irradiation on the hypersensitive area showed positive effect in some case where the irradiation showed no effect on either the nerve foramen or the around the root apex. There was no effect on either the hypersensitive area or the around root apex, then cross-over irradiation to the nerve foramen didn't show any favalable effect.
3. After 1 week, for effective cases in the groups, there was high percentage of pain reoccurence.
