RESUMO
Two dental cleansing products, Rc-Prep and Largal Ultra, were subjected to a comparative study, evaluating their efficacy in vitro on 15 recently-extracted dentary units, through optic microscopy applied on the dentine wall of the instrumented root canal. Both materials were applied on separate hemisections of the canal during 15 minutes intervals, with two applications on each canal. Rc-Prep was observed to have a slight, not significant advantage over Largal-Ultra in its cleansing effect over the dentine smear, although the compact, granular and amorphous layer of dentine smear over the root canal wall, blocking the entry to dentine channels, persisted after use of both products. In view of conditions observed in the dentine walls, the authors assume that adhesion and adaptation of obturating materials over these structures is exceedingly difficult. Although variability was not considered as is usual in clinical studies, in vitro evaluation as observed in this study allows a more accurate comparative analysis, since it was performed on one individual tooth, with analogous instrumentation and on dentary tissue with similar characteristics.