title: Antibacterial Efficacy of Calcium Hydroxide and Chlorhexidine Mixture for Treatment of Teeth with Primary Endodontic Lesions: A Randomized Clinical Trial.
abstract: BACKGROUND
  This study compared the root canal microbial count of necrotic teeth after irrigation with 6% sodium hypochlorite (NaOCl) (single session treatment) and two-session root canal treatment with two-week application of calcium hydroxide (CH) mixed with 0.2% chlorhexidine (CHX) as intracanal medicament.
  
  
  METHODS
  In this randomized clinical trial, single-rooted necrotic teeth were divided into two groups. Root canal was irrigated with 2 mL of 6% NaOCl in one group, and a mixture of 0.2% CHX and CH powder as an intracanal medicament for two weeks, in the other group. Root canal samples were obtained before and after the intervention and number of colony forming units (CFUs) was counted in each phase.
  
  
  RESULTS
  The reduction ofEnterococcus faecalisCFU was not significantly different between the two groups (P=0.233) but the CFU of aerobic and anaerobic bacteria was significantly lower in CH+CHX group (P<0.001).
  
  
  CONCLUSIONS
  Two-week application of CH+CHX caused significant reduced the aerobic, anaerobic andE. faecaliscolony counts. Thus, it may be beneficial to carry out primary root canal treatment of necrotic teeth with endodontic lesions in two sessions with intracanal medicaments to achieve predictable results.
authors: Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Zakiyeh
authors: Z
authors: Donyavi
authors: Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Parastoo
authors: P
authors: Ghahari
authors: Department of Pediatric Dentistry, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Mohammad
authors: M
authors: Esmaeilzadeh
authors: Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors: Mohammadjavad
authors: M
authors: Kharazifard
authors: Department of Medical Microbiology, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Rasoul
authors: R
authors: Yousefi-Mashouf
keywords: Calcium Hydroxide; Chlorhexidine; Endodontic Treatment; Periapical Abscess; Root Canal Therapy