THE EFFECT OF PULPOTOMY USING CO2 AND ND-YAG LASERS ON DENTAL-PULP TISSUE

The histological response of the dental pulp after laser irradiation w as studied. After pulpotomy was performed in the premolar and molar te eth of dogs, the exposed pulp tissue at the root canal opening was las ed using either a CO2 or Nd:YAG laser. The laser parameters were 2 W, 10 ms, 5 times per second for 1, 2 and 3 s for CO2 laser and 2W, 20 pu lses per second for 1, 2 and 3 s for the Nd:YAG laser. Observations we re made 30 and 45 days after treatment. The results revealed that lase r irradiation caused carbonization, necrosis, infiltration of inflamma tion cells, oedema and haemorrhage in the pulp tissue. Under the condi tions of this experiment, there was little histological evidence of re pair to the treated pulp with a newly formed dentine barrier, which wa s in contrast to the control samples treated with a calcium hydroxide- containing cement (Dycal).