Response of feline intradental nerve fibers to tooth cutting by Er:YAG laser.
OBJECTIVE
The aim of this study was to investigate the response of intradental A- and C-fibers during tooth cutting by Er:YAG laser.


METHODS
Bipolar electrical stimulation was applied to the cat's canine to identify functional single nerve fibers of the inferior alveolar nerve. The tip of the canine tooth was cut in 0.5-mm steps until the pulp was exposed. Teeth were alternately cut by using Er:YAG laser (50 mJ, 5 pps) and micromotor under water cooling. The nerve response recorded from the single nerve fibers during laser cutting was compared with that during micromotor cutting.


RESULTS
All 26 A-fibers responded to laser cutting with high frequency of nerve firings. The nerve firing rate was significantly higher during laser cutting compared with that during micromotor cutting of superficial dentin (Chi(2) test, P < 0.05) but was not significantly different at deep dentin (P > or = 0. 05). Nine of 11 C-fibers responded to laser cutting when the deep dentin was cut. Among those nine nerve fibers, three also showed a low frequency response to laser cutting of the superficial dentin.


CONCLUSIONS
During the tooth cutting, Er:YAG laser was more effective in activating intradental A-fibers compared with micromotor and also caused the activation of intradental C-fibers.
Chaiyavej
S
S
Pulp Biology and Endodontics, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
Yamamoto
H
H
Takeda
A
A
Suda
H
H
D000818:Animals; D002415:Cats; D003481:Cuspid / Q000294:innervation*; D003782:Dental Pulp / Q000294:innervation; D003804:Dentin; D007834:Lasers; D009412:Nerve Fibers; D009475:Neurons, Afferent