Comparison of microleakage of cast posts and intracanal pins

The seal provided by a root canal filling may be compromised by post space preparation. The aim of this study was to compare coronal microleakage around cast posts and prefabricated pins. Thirty-eight extracted single-rooted, maxillary human teeth were prepared with step back method and filled with gutta-percha and sealer. After removing 8 mm of coronal gutta-percha with peeso- reamer drills #2 in twenty canals, the teeth were divided into three groups: cast post and core, prefabricated pin, and gutta-percha [without any post or pin]. After thermocycling, the samples were immersed in India ink for seven days. Finally, the specimens were cleared and the coronal microleakage of dye was then measured by the stereomicroscope. The data were analyzed by One-way ANOVA and Tukey HSD tests. According to the results, the mean dye penetration in cast posts, pins, and group without post or pin was 3.3 [0.39], 5.2 [0.47], and 7.2 [0.15] mm, respectively. There was no statistically significant difference between the groups [P>0.05]. Considering the importance of adequate filling of crown for prevention of microleakage, the method for coronal filling must be selected with caution. According to the results of this study, no significant difference between microleakage of cast posts and prefabricated pins was observed

[Evaluation of antibacterial effects of different calcium hydroxide compositions on planktonic enterococcus faecalis]

Calcium hydroxide has a pronounced antimicrobial activity against most of the bacterial species found in infected root canals and endodontic infections. It is one of the most frequently used intracanal medications in endodontic therapy. The objective of this study was to determine the antimicrobial efficacy of six calcium hydroxide formulations [mixed with saline, lidocaine 2%, chlorhexidine 2%, chlorhexidine 0.2%, Iodine Potassium iodide [IKI] 2%, and glycerin] on Enterococcus faecalis using agar diffusion test. Twelve culture plates were incubated with Enterococcus faecalis. Five cavities were made in each plate with 5 mm diameter and 4 mm depth. Two plates were randomly considered for each calcium hydroxide formulation and filled completely with creamy mixture of tested materials. The plates were incubated at 37degree]C for 48 hours. The diameter of inhibition zone around each well was recorded in millimetres and data were submitted to ANOVA and Tukey tests. The results of this study showed that all tested calcium hydroxide pastes had good antimicrobial activity. The antimicrobial activity of calcium hydroxide mixed with lidocaine, chlorhexidine 2% and IKI 2% were significantly greater than that of calcium hydroxide mixed with saline [P<0.001]. No significant differences in the antimicrobial were found between the other groups [P>0.05]. Considering the results of this study, lidocaine 2%, chlorhexidine 2% and IKI 2% are suggested to be used for preparation of calcium hydroxide paste. Further studies with different methods are needed for confirming these results.

[ comparison of antibacterial effects of three sealers used in endodontic treatments]

Antibacterial effect of the sealers which are used in root canal therapy is a factor which increases the rate of success in root canal therapy. The aim of this study was to compare the antibacterial effect of three sealers [ZOE, AH26, Dorifill] on two bacterial species, staphylococcus aureuse and streptococcus mutans immediately after mixing and one week after mixing. For conducting this experimental study the bacteria were provided in isolated microbial species and a standard concentration from bacteria were cultured on the blood agar media with muller-Hinton base. The 5 millimeter diameter wells in the central area of the plate were punched. The fresh mixture of the mentioned sealer were put in the wells. The same process was performed on the sealers one week after mixing. After 24 hours incubation the diameters of the inhibitory zones in 4 directions were measured with boley - gauge. The results showed that the fresh mixture of AH26 for both bacterial species was significantly more effective than the others [P=0.001]. One week after mixing for both species ZOE was significantly more effective than AH26 and AH 26 was significantly more effective than Dorifill [P=0.001]. With regard to acceptable antibacterial effects of these three sealers performing studies about other properties of these sealers specially ZOE, is suggested