This study evaluated in vitro the amount of heat elevation inside the pulp chamber which is very
critical for the vitality of pulp tissue during enamel etching by using diode laser (1064).Thirty-six freshly
extracted single-rooted human teeth were selected. The teeth were divided into four groups of three each and
irradiated by using diode laser (1064) on their enamel surfaces. In groups 1, 2 the enamel surfaces were
irradiated with power (4.5,5)watt, Continuous wave. In groups 3,4 the Power(4.5,5)watt, pulse wave(pulse
duration 50msec,pulse repetition 5pulse/sec)at time(10,15,20)sec for all groups. The temperature was monitored
by means of a thermocouple positioned in the pulp chamber to assess pulpal temperature during and before
enamel etching. Temperature measurements were repeated three times for every group after two hour standby
period. Mean values were compared statistically with t-test to determine the significant difference among the
tested groups at (p<0.05) level of significance. The highest temperature rises (18.66±3.05)o
c occurred during
enamel etching at power5watt, Continuous wave, time 20 sec for every test period. The least temperature
increase (2.66±0.57)o
c occurred during enamel etching at power5watt, Pulse wave, time 10sec for every test
period. These results indicated that the choice of laser types (Continuous or Pulse) and irradiant time is
important during enamel etching to avoid any thermal damage to the pulp.