Antimicrobial Substantivity over Time of Chlorhexidine and Cetrimide

Introduction: To reach an adequate control of dentin infection and to promote success in endodontic therapy, antimicrobial irrigating solutions with confirmed substantivity are recommended. The aim of the present study was to evaluate the antimicrobial substantivity against Enterococcus faecalis of a dentin-volumetric unit exposed for 1 minute to chlorhexidine (CHX) and cetrimide (CTR). Methods: Standardized coronal dentin blocks of human molars, with and without collagen, were treated for 1 minute with 0.2% and 2% CHX and 0.2% CTR. Afterwards, they were exposed to E. faecalis suspension to determine the antimicrobial substantivity over a period of 60 days. Results were analyzed by means of Kaplan-Meier survival analysis (P < .05). Results: A direct relationship was seen between CHX concentration and survival time, and the most statistically significant results were obtained in specimens with collagen. CTR showed intermediate survival values close to those of 2% CHX. Conclusions: The present study shows that 2% CHX used for 1 minute provides the longest substantivity followed by 0.2% CTR when applied to a dentin-volumetric model. (J Endod 2012;38:927-930)