STUDY OF THE ND-YAP LASER - EFFECT ON CANAL CLEANLINESS

The aim of this study was to evaluate the canal cleanliness achieved b y five different preparation techniques, including use of the laser, B y randomization, the palatal roots of 50 maxillary molars were assigne d to one of five groups, During all preparations, a sodium hypochlorit e irrigant was used, The following techniques were studied: (A) manual instrumentation (serial preparation), (B) laser preparation (Nd:YAP l aser), (C) manual preparation with laser as adjunct, (D) manual prepar ation with a subsonic device as adjunct (MM 3000 with shapers), and (E ) manual instrumentation with a subsonic device and laser as adjuncts (MM 3000 with shapers, Nd:YAP laser), The canal wall surfaces were exa mined under a scanning electron microscope at all levels with a new me thod using grid incrustation on the microscope screen, Techniques A an d C differed from each other only by the size of the debris particles, which were smaller for the C preparation, For laser preparation (B) t here was little increase in canal diameter increase, and a substantial amount of debris was present, The differences between techniques A, C , and D were not significant, The use of the subsonic device and laser together as adjuncts (E) showed the cleanest preparation with very li ttle debris, opened tubules, and very small particle size, This result suggests that the laser has a potential in ensuring optimal canal cle anliness.