Effect of apically separated rotary instruments on bacterial leakage of obturated root canals using resilon.

The purpose of this study was to determine the effect of a separated rotary instrument on the time required for bacterial penetration of obturated root canals using Resilon. Eighty-four extracted human maxillary premolars with single canals were used in this study. Group 1 consisted of teeth obturated with gutta-percha and AH-26 sealer (n=15); Group 2 consisted of teeth obturated similarly to Group 1 but without a separated file; Group 3 consisted of teeth obturated with Resilon and Epiphany sealer (n=15); and Group 4 consisted of teeth obturated similarly to Group 3 but without a separated file. Six teeth were used as positive controls, and six teeth were used as negative controls for each experimental group. Negative controls were obturated similarly to experimental teeth. On the other hand, positive controls were obturated with gutta-percha or Resilon without sealer. A suspension of Enterococcus faecalis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth during a three-month period. No significant difference between experimental groups was observed. However, differences between experimental groups and control groups were statistically significant.

Antimicrobial effect of three new and two established root canal irrigation solutions.

This study sought to assess the efficacy of two established and three relatively new root canal irrigants against five different microorganisms using the agar diffusion method. Sodium hypochloride (NaOCl)-based irrigants demonstrated the most effective antimicrobial activity.

Bacterial microleakage and post space timing for two endodontic sealers: an in vitro study.

AIM: The effects of immediate versus delayed post space preparation on the apical seal using resin and zinc oxide eugenol (ZOE) sealers were compared by a bacterial leakage model. METHODOLOGY: Eighty-six premolars were randomly assigned to four experimental groups of 20 teeth. Three teeth were assigned to each control group, either positive (filled only with guttapercha) or negative (not obturated but root surfaces completely covered). Obturation was achieved by gutta-percha with resin or gutta-percha with a ZOE sealer and lateral condensation technique. Post space was prepared either immediately or a week later, while the obturated teeth had been stored in 100 percent relative humidity at 37 degrees C. The teeth were inserted into plastic vials and suspended in glass bottles. All teeth were covered with cyanoacrylate and layers of nail varnish but the apical 3 mm and were sterilized using gamma rays. Phenol red lactose broth was inoculated into the vials. Staphylococcus epidermidis was introduced into the root canal access of the teeth. Turbidity of the broth in the vials (discoloration) was evaluated daily for a period of 70 days. The data was analyzed statistically with Pearson Chi Square and two ways with ANOVA at 45 days and 70 days. RESULTS: When the depth of time was considered, the mean time of leakage showed no differences between immediate and delayed preparation for resin AH26 versus ZOE Dorifil at 45 and 70 days (p = 0.37 and p = 0.217, respectively). In 45 days, considering the number of teeth with leakage, there was a significant difference between immediate preparation and delayed preparation in AH26 sealer groups (p = 0.028). No difference was present between immediate and delayed preparation groups for the ZOE sealer groups (p = 0.14). CONCLUSION: According to the results of this study and despite type of sealer, immediate post space preparation did not achieve better sealing than delayed post space preparation. Resin AH26 showed the least leaking teeth in 45 days, but it made no difference in 70 days.