Scanning electron microscope study on the efficacy of root canal wall debridement of hand versus Lightspeed instrumentation

Aim The aim of this in vitro study was to compare the efficacy of root cana l wall debridement following hand versus LightSpeed(TM) instrumentation. Methodology Twenty recently extracted single-rooted teeth were paired and r andomly placed into two treatment groups of 10 teeth each. In group 1, a st ep-rooted instrumentation without: initial coronal flaring with stainless s teel Hedstroem fries was used; group 2 was instrumented with Ni-Ti LightSpe ed(TM) instruments, Both groups had the same irrigation regimen: 2.5% NaOCl and a 15% EDTA solution, The teeth were then decoronated and each root spl it longitudinally inter two halves to be examined using the scanning; elect ron microscope (SEM). The presence of superficial debris and smear layer wa s evaluated by a standardized grading system, and the resulting scores subm itted to nonparametric statistics. Results Under the conditions of this study, the removal of superficial debr is was generally excellent with both canal preparation. techniques resulted in variable presence of residual smear layer, with a canal wall covered by smear layer as the predominant characteristic. Generally, the amount of sm ear layer was greater in the apical than in the middle third of the root, h owever, this difference was statistically significant (P < 0.005) only in h and-instrumented teeth. The use of LightSpeed(TM) instruments was associate d with significantly more (P < 0.05) smear layer presence in the middle reg ion of the root when compared with hand instrumentation. In addition, less smear layer was present in the apical region following LightSpeed(TM) instr umentation than stainless steel hand files, but this difference was not sta tistically significant. Differences in debridement between the two halves o f the same root were more evident with LightSpeed(TM) than manual instrumen tation, however, there was no statistical significance. Conclusions It may be inferred that the choice between hand and LightSpeed( TM) instrumentation should be based on factors other than the amount of roo t canal debridement, which does not vary significantly according to the ins truments used.