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Pulpal blood flow recorded from human premolar teeth with a laser Doppler flow meter using either red or infrared
Kanittha Kijsamanmith1, Siriporn Timpawat, Noppakun Vongsavan
1Department of Physiology and Biochemistry, Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand.
Objective:
To compare red (635 nm) and infrared (780 nm) light for recording pulpal blood flow from human premolar teeth.
Design:
Recordings were made from 11 healthy teeth in 9 subjects (aged 16-30 years) using a laser Doppler flow meter (Periflux 4001) equipped with both red and infrared lasers. Average blood flow signals were obtained with both light sources alternately from each tooth under five conditions: intact tooth without opaque rubber dam, intact tooth with dam, after injecting local anaesthetic (3% Mepivacaine) (LA) over the apex of the tooth and cavity preparation to almost expose the pulp, after removal and replacement of the pulp, and with the root canal empty.
Results:
With infrared light, the dam significantly decreased the mean blood flow by 80%. Injecting LA and cavity preparation had no significant effect. Removal and replacement of the pulp reduced the mean blood flow by 58%. There was no further change when the pulp was removed. With red light, the dam reduced the signal from intact teeth by 60%. Injecting LA and cavity preparation had no significant effect. The signal fell by 67% after pulp removal and replacement and did not change significantly when the pulp was removed.
Conclusions:
Opaque rubber dam minimises the contribution of non-pulpal tissues to the laser Doppler signal recorded from premolars. Using dam, the pulp contributed about 60% to the blood flow signal with both red and infrared light. The difference between them in this respect was not significant.
