Penetration depth of laser Doppler flowmetry beam in teeth

Objective. The aim of this study was to determine the penetration depth of laser light in teeth for contact and noncontact probe tip. Study design. Fifty-one freshly extracted human mature maxillary and mandibular single rooted teeth were selected for the study. A laser Doppler flowmeter was used as a laser source. A digital camera was used to take pictures (with "night shot" mode in total darkness). When probe tip was in contact and when it was I mm away from the tooth, the depths of the areas illuminated in high and low density were measured. Results. In contact probe, root was illuminated to 4.28 +/- 0.14 mm depth with high density and 13.27 +/- 0.27 mm depth with low, density. In noncontact probe, 4.36 +/- 0.16 mm with high density and 13.28 +/- 0.30 mm with low density of illumination were seen on the root. Between contact and noncontact probe situations the difference was not statistically significant in the depth of illumination. On the other hand, in both groups the difference between areas illuminated in high and low density was statistically significant (P < .05). Conclusion. Contact or noncontact of the probe on tooth surface did not show any significant difference in light penetration. Besides, we think that, for the present, it is impossible to eliminate the contarnination from periodontal tissues completely even if the necessary precautions (periodontal paste etc.) are taken.