Pages: 43-50

Abstract

Aim: E.feacalis is one of the most common species isolated from the canals after instrumentation and medication. Therefore, a variety of intracanal medicaments such as Ca(OH)2 have been recommended for interappointment periods with the aim of complete disinfection of the root canal. It has been shown that this bacteria may remain in the canal even after obturation of root canal system. There is controversy regarding the effectiveness of interappointment medicaments and the aim of this study was assessing the effectiveness of medication with calcium hydroxide after obturation of the root canal system. Materials and methods: Access preparations were done on 66 extracted human teeth which were consequently infected with E.faecalis for 3 weeks. The canals were prepared by NiTi rotary instruments and irrigated with saline solution. The specimens were divided into two groups. In the first group, Calcium hydroxide was used as intracanal medication for 7 days followed by obturation of root canal system with gutta percha and sealer. The specimens of group 2 were obturated with gutta percha and sealer immediately. In the next stage, all teeth were incubated for 60 day at 37°c. Each specimen was transversally cut with diamond disk in middle of the root. Dentine chips were removed from two different depths of the middle intra walls with two sequential sterile round burs (iso 10,16) using a low speed handpiece. The Samples obtained by each bur were immediately collected in separate test tubes containing BHI broth medium, and then cultured in agar plates. Colony forming units were counted after 24 hours at 37°c. Data were ranked and analyzed using the Mann-Whitney U test and chi-square test. Results: E. Faecalis was recovered from 87.9% of superficial dentin and 78.3% of deep layer dentin in Group1 and 39.4% of super facial dentine and 24.2% of deep layer dentine in group 2. Based on colony counting, which were 41.92 and 42.4 colony count/mL(×10-2 ) for superficial and deep dentin respectively in group 1 and 25.08 and 24.8 colony count/mL(×10-2) for superficial and deep dentine respectively in group 2; Growth rate of E.feacalis was higher in superficial and deep layer dentine when calcium hydroxide was used. Conclusion: Even after 60 days, E.faecalis remained viable inside dentinal tubules. The result supports the findings which indicate that interappointment calcium hydroxide may not add to the antibacterial effectiveness of the treatment.