Measurement of vaporization cavity after CO2 laser irradiation on bovine dentin

Lasers are used for various clinical applications in dental practices, and many studies have examined the effects of lasers with different applications on enamel and dentin. The CO2 laser was introduced into the dental clinic for the removal of caries and for cavity preparation of hard tissues, in anticipation of replacing air turban and micromotor devices. The aim of this study was to examine dentin structural changes by measuring 3-dimensional diameter, depth, and volume in bovine teeth irradiated with a CO2 laser at 1, 3, or 5 W. According to our measurements, a vaporization depth of 400 μm was created by irradiation for a mere 100 ms in the case of 3 W irradiation and 500 μm in the case of 5 W irradiation. Further, at the same output power, the pulse mode transmitted energy to deeper layers of the tooth as compared with the continuous wave mode, indicating that the pulse mode has more penetrating power than the continuous wave mode. Moreover, the depth of cavity that after laser irradiated was > 500 μm at output power 5 W. Thus, irradiation at high output power and the influence of pulse mode on the pulp tissue cannot be disregarded. That is to say, it is important to consider irradiation output power, mode, direction, and distance when lasers are used for adjacent to pulp of tooth that primary incisors and deep cavities.