The key fields of research of dental lasers have focused oil the use of different wavelengths on hard and soft tissues; however it is not clear whether they can be used for tooth preparation for full coverage restorations or not. The objective of this study was to investigate the possibility of tooth preparation for full coverage restorations using a scanner assembly added-on Er:YAG laser system and compare the tooth preparation durations performed with dental drills and the laser. The 20 freshly extracted human molar teeth were allocated to two groups (A and B) of 10. Group A was prepared with dental drills, whereas group B was prepared with a scanner assembly added-on Er:YAG laser system. The preparation duration means of the groups were calculated and analyzed by one-way analysis of variance. The difference between group A (20, 2 +/- 1, 9 min) and B (45, 2 +/- vertical bar 3, 1 min) (P < 0.01) was significant. Laser preparation took more time than the conventional rotary instrumentation. The recommended amount of tooth reduction for full coverage restorations could be accomplished by the laser tooth preparation. Tooth preparation using Er:YAG laser with laser application for wide area system took more time than the rotary instruments. (C) 2009 Laser Institute of America.