Histologic analysis of the effect on dental pulp of a 9.6-microm CO(2) laser

Both patients and dentists would like a replacement of the dental drill. During the last decade, lasers have been investigated as a possible replacement. For lasers to be accepted, studies must show that their effect on the dental pulpal tissues is equal to or less noxious than those effects caused by the dental handpiece (drill). In this study, two laser systems were used; the first was a breadboard CO(2) laser and the second a prototype clinical CO(2) laser system both emitted 60-micros-long pulses of 9.6-microm radiation. On the delivery system of both lasers, a scanner moved the focussed beam in a circular pattern and a water spray system served to cool the ablation site. Both lasers were used to create holes of similar dimensions in canine teeth. The treated teeth were then restored and harvested at either 4 days or 4 weeks. The teeth were decalcified, sectioned, and stained for examination via light microscopy. The histologic examination revealed normal pulpal tissues in the canine teeth treated with both CO(2) lasers. Some histologic sections showed an increase in the predentin layer, 28 days after laser treatment. While many histologic sections showed normal pulpal architecture following handpiece treatment, some sections showed total disruption of the normal pulpal histology. Histologic evaluation revealed that the lasers produced no noticeable damage to the dental pulpal tissue and appear to be a safe method for removing dental hard tissues. From this study, it appears that 9.6 microm CO(2) laser does not cause damage to the dental pulpal tissues in dogs.