[Comparison of the apical leakage of root canals filled with MTA with those filled with gutta percha and lateral condensation technique]

Sealing the root canal system is of great importance in endodontic treatment especially in infected teeth. Several materials have been introduced for this purpose. The aim of the present study was to evaluate the sealing ability of MTA as an orthograde root filling material and compare it with laterally condensed gutta-percha with sealer. Thirty-six extracted human maxillary central and canine teeth were used in this experimental study. After preparation and surface disinfection with 1% NaOCI solution, the crowns of the teeth were cut at cement-enamel junction. Roots were randomly divided into four groups: two experimental groups of 15 roots each [gutta-percha with AH26 sealer and MTA] and two control groups of 3 roots each [positive and negative]. After root canal preparation and filling, the sealing ability of each technique was assessed by immersion in 1% methylene blue dye for 72 hours. Then the teeth were cleared and the extent of dye penetration was measured with a stereomicroscope. Data were analyzed by T-test with P<0.05 as the level of significance. The results showed that the mean microleakage was 1.1 mm [SD=2.1] in the gutta percha group and 3.4 mm [SD=2.1]in the MTA group. This difference was statistically significant [P=0.013]. Based on the results of this study, canal obturation with gutta-percha and AH26 sealer may provide a better apical seal compared with MTA. However, further studies on microbial leakage are needed for more precise evaluation of the sealing ability of MTA

[Comparative evaluation of the sustainability of antibacterial effects of doxycycline, chlorhexidine and sodium hypochlirite in bovine root dentine]

One of the most important objectives of root canal therapy is the elimination of micro organisms from the root canal system. In order to achieve maximum disinfection of the root canal system, irrigation should be done during treatment. The aim of this in vitro study was to compare the sustainable antimicrobial activity of 2% chlorhexidine solution, 100 mg/ml doxycycline solution, and 2.6% NaOCL solution in bovine root dentine. Fifty dentine tubes prepared from intact freshly extracted bovine maxillary central incisors were infected invitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups according to the intracanal irrigant used. Group1: 100mg/ml doxycycline hydrochloride solution [n=10]; Group2: 2% chlorhexidine gluconate solution [n=10]; Group 3: 2.6% NaOCL solution [n=10]; Group 4: Infected dentinal tubes [positive control] [n=10] and Group 5: Sterile dentinal tubes [negative control] [n=10]. Dentine chips were removed from the canal with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing 1 ml tryptic soy broth [TSB]. Thereafter, 100 micro1 from each test tube was cultured on blood agar and number of CFUs was counted. The number of CFUs from three experimental groups were compared using Univariate analysis of variance [ANOVA] and Duncan analysis .Sustainable antimicrobial effect was evaluated at days 0,7,14 ,21 and 28. The number of CFUs in all three experimental groups were minimum in the first cultures, but the results obtained were significantly different from each other at any time period [P<0.05] .In the first culture, 2.6% NaOCL group [0.400 +/- 0.699]and 100 mg/ml doxycycline HCL group [4.700 +/- 3.683]showed the lowest and highest number of CFUs respectively . In each group, the number of CFUs increased significantly with time -lapse [p<0.05] .NaOCL did not have a sustainable effect. It can be concluded that chlorhexidine and to some extent, doxycycline HCL may be useful as sustainable antimicrobial root canal irrigants