Intrapulpal Temperatures During Pulsed Nd:YAG Laser Treatment of Dentin, In Vitro

Abstract

Lasers are being used for soft tissue removal, caries removal, and treatment of root surface sensitivity. One concern for laser safety is that the heat produced at the irradiated root surface may diffuse to the pulp causing irreversible pulpal damage. To test this heat diffusion, copper-constantan thermocouples were inserted into the radicular pulp canals of extracted teeth. Simulating direct exposure which might occur during gingival excision, superficial caries removal, and modification of the dentin surface for treatment of root surface sensitivity, a 2 mm2 area of the external root surface was uniformly irradiated with a pulsed Nd:YAG laser using a 320 microns diameter fiber optic contact probe. Power was varied from 0.3 to 3.0 W with frequencies of 10 and 20 Hz. Temperature changes during cavity preparations using a high speed handpiece with air coolant were also recorded. Repeated measures ANOVA (P < or = 0.05) indicated that intrapulpal temperatures increased as a function of power, frequency, and time. Intrapulpal temperatures decreased as remaining dentin thickness (0.2 to 2.0 mm) increased for each laser parameter. Irradiation of dentin using a Nd:YAG pulsed laser, within the treatment times, powers, and frequencies with adequate remaining dentin thickness, as outlined in this paper, should not cause devitalizing intrapulpal temperature rises.

Treatment of dentine hypersensitivity by lasers: a review

“…However, treatment effects must be well controlled when using black ink as absorption enhancer. It was reported that irradiation at 2 W and 20 pps for 10 sec induced pulpal temperature rises through 2 mm of remaining dentine thickness of 13.4 aeC (White et al 1994). Using the CO 2 laser, no damage was reported after pulpal exposure to 3 W of power for 2 s in the CW mode using monkeys and dogs (Melcer et al 1985).…”

Lasers and soft tissue: 'fixed' soft tissue surgery

“…This risk can exist through the penetration of short wavelengths or the conductive heat effects arising from long wavelength char that is super-heated. [5][6][7][8][9] It is advisable, therefore, to assess the thickness, vascularity and position of any target 6,[10][11][12] during the removal of a giant cell granuloma. Laser therapy has been cited as a possible modality in treating this condition.…”

Protective Effect of Adhesive Systems associated with Neodymium-doped Yttrium Aluminum Garnet Laser on Enamel Erosive/Abrasive Wear

“…The energy parameters used in our study, which were 80 mJ and 10 Hz, are considered safe, not causing injuries to the pulp or necrosis. White et al 25 conducted a study in which various power parameters were tested to evaluate the temperature in the pulp chamber when applied at the pulpal cavity preparation wall in dentin. Those evaluations were conducted with a distance of 0.2 to 2 mm from the pulp, and the temperature was measured by thermocouples.…”

“…Those parameters were based on previous studies and considered safe, not causing injuries to the pulp. 8,24,25 After that, light curing of the adhesive was performed for 10 seconds. In Group L, only the irradiation of Nd:YAG laser over enamel surface was performed, using the same parameters described earlier, while Group C received no treatment (control).…”