This in vitro study compared temperature rises during cavity preparation wi
th an Er:YAG laser, Nd: YAP laser, and a high-speed handpiece, Eighteen tee
th were sectioned longitudinally and divided into six groups: group 1 was t
reated with a carbide bur on a high-speed dental handpiece; group 2 was tre
ated with an Er:YAG laser with an energy of 140 mJ, a pulse repetition rate
of 4 Hz; and group 3 was treated with an Nd:YAP laser with an energy of 24
0 mJ, a pulse repetition rate of 10 Hz, In these groups no water cooling wa
s used. Groups 4 to 6 were treated in the same way, but with water spray. T
emperature increases were measured at different dentin thicknesses by a mic
rothermocouple attached to the inner side of the pulp chamber. Water coolin
g was essential to reduce temperature effects in all groups. Nd:YAP laser i
nduced significantly higher temperature rises than Er:YAG or handpiece, Tem
perature response to the Er:YAG laser and the handpiece seemed to be simila
r.