Effects of CO 2 Laser Irradiation on Treatment of Hypersensitive Dental Necks: Results of an in Vitro Study

Various methods for treatment of hypersensitive dental necks have been developed during the past few decades. The exposure of dentinal tubules to chemical, thermal, and mechanical influences in the oral environment is considered the cause of dentin hypersensitivity. Stimuli can be transmitted as far as the sensitive nerve endings by dentinal tubules. As a result treatment methods are based on the attempt to seal exposed dentinal tubules permanently. The main sealing materials are fluoride preparations, strontium chloride, and hydroxyapatite. They must be applied periodically to achieve permanent freedom from pain. A new method to treat hypersensitive dental necks is laser irradiation. In our in vitro study, we treated extracted human teeth with a CO₂ laser in the cervical region. The necks of these teeth had been exposed prior to extraction thereby causing dentin hypersensitivity. Scanning electron microscopy after treatment revealed almost complete closure of the dentinal tubules. We applied a thin layer of stannous fluoride gel to 10 teeth prior to laser treatment. Electron probe microanalysis (EPMA) revealed that tin was present within the sealed tubular openings. Subsequent temperature measurements showed that laser treatment caused a maximum increase in temperature within the pulp cavity by 2.5°C.