M. Luomanen et al., HEALING OF RAT MOUTH MUCOSA AFTER IRRADIATION WITH CO2, ND-YAG, AND CO2-ND-YAG COMBINATION LASERS, Scandinavian Journal of Dental Research, 102(4), 1994, pp. 223-228
The healing process of wounds made by a combination laser was studied
in 90 rats. The laser system enabled both separate and combined use of
CO2 and Nd:YAG laser irradiations. The laser wounds and the control e
xcision wounds made by alligator forceps appeared on both sides of the
tongue. Specimens from the wound sites were taken immediately, 6 h, a
nd 1, 2, 4, 7, 11, 21, 28, and 42 days after surgery. The wound-healin
g process was studied by macroscopic evaluation before preparing the s
pecimens for light microscopy. Some differences were noted in the woun
d-healing process among the three groups into which the experimental a
nimals were divided. Tissue coagulation damage was most extensive in t
he Nd:YAG laser sites, where it was observed in its full extent 4 days
after surgery. Epithelial cells were seen to begin to proliferate in
all the wounds 6 h after surgery. Re-epithelialization was completed b
y between 7 (CO2) and 21 days (Nd:YAG) at all the wound sites. The inf
lammatory cell infiltration was more prominent in the Nd:YAG and the C
O2-Nd:YAG combination laser wounds than in the CO2 and excision wounds
during healing. Tissue regeneration occurred faster with less contrac
tion in the combination CO2-Nd:YAG wounds than in Nd:YAG wounds. The b
est macroscopic healing result was seen in the CO2 wound sites. The co
mbination laser was effective both at cutting and at coagulating tissu
e. Combining the CO2 and Nd:YAG laser irradiation into one beam result
ed in a greater incision depth than what could have been expected from
using the two lasers separately.