This case report describes the healing of a large periapical lesion without apical surgery.  In this paper, s 35 year-old female with a large lesion from the apices of her teeth 22-27 is presented. During treatment procedure 2.5% sodium hypoclorite solution was used for irrigation and calcium–hydroxide was used as intracanal anti-microbial dressing. Periapical healing was observed in radiographic examinations at 6-month and 1 and 2 year-follow-up visits.

Background and purpose: Mechanical and chemical canal preparations are not capable of eliminating all microorganisms from dentinal tubules, so using medical intervention is necessary to fulfill this task. The aim of this study was to compare the antimicrobial effect of Carvacrol and Calcium hydroxide against Enterococcus faecalis in different layers of dentin and different time intervals.

Materials and methods: An experimental study was performed in which 70 upper anterior single-rooted teeth were extracted and after separating middle of roots, the inner diameter of canals was equalized. After sterilization the specimens were subjected to Enterococcus faecalis suspension and then randomly divided into four groups of 15 each and one control group including 10 samples. Carvacrol was placed in canals for 5 minutes, 48 hours and one week and Calcium hydroxide was placed in canals for one week. Finally, dentinal debris obtained from canal preparation were incubated in culture medium and presence of Enterococcus faecalis was assessed. Statistical analysis was performed using Chi-square test in SPSS.

Results: In the inner layer of dentin, success rate of Enterococcus faecalis elimination was 100% for Carvacrol at all time intervals and 80% for Calcium hydroxide after one week. In the middle layer of dentin, the success rate of Carvacrol was 93% after 5 minutes and 87% after 48 hours and one week, but success rate of Calcium hydroxide after one week was 73%. There were no significant differences in antimicrobial effect between the groups (P>0.05).

Conclusion: Carvacrol can eliminate Enterococcus faecalis in shorter time intervals compared with Calcium hydroxide.

Background and purpose: Calcium hydroxide and Chlorhexidine are among common intracanal medications. Recently an herbal composition named Carvacrol has been suggested as an intracanal medication. The purpose of this study was to compare antimicrobial effect of Carvacrol, Chlorhexidine and Calcium hydroxide on Enterococcus faecalis.

Materials and methods: In this experimental study, 56 single-rooted teeth were extracted and after canal preparation, they were randomly divided into three groups (n= 16) and 2 positive and negative control groups (n= 4 per group). After sterilization by autoclave, all samples except negative control group were contaminated with Enterococcus faecalis. The root canals in group 1 were filled by Calcium hydroxide paste. Paper cones impregnated by 0.2% Chlorhexidine and 94% Carvacrol were placed in working length of root canals in group 2 and 3, respectively. Negative control group was assessed without contamination and no medication was used in positive control group. After incubation of specimens for 48 hours and canal irrigation, a sample was taken from each canal and bacterial colony growth was assessed in BHI agar. Data analysis was done in SPSS ver.20 applying Chi-square and Fishers exact test.

Results: All three groups were found effective in eliminating Enterococcus faecalis and there were no significant differences in antibacterial effect between these groups (P= 0.99).

Conclusion: Carvacrol can be recommended as an effective herbal medication for intracanal irrigation.