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.

Effect of pretreatment prednisolone on postendodontic pain: a double-blind parallel-randomized clinical trial.

INTRODUCTION: Effective management of endodontic pain represents a continuing challenge. This study evaluates the use of a preoperative, single oral dose of prednisolone for the prevention and control of postendodontic pain. METHODS: Forty patients were randomly assigned to 2 groups, placebo and prednisolone (30 mg). The medications were administered 30 minutes before the start of standard endodontic treatment. Postoperative pain was assessed after 6, 12, and 24 hours by using a visual analogue scale. RESULTS: The outcome showed that prednisolone resulted in a statistically significant reduction in postendodontic pain at 6, 12, and 24 hours (P < .0001). No side effects were reported for any of the medications used. CONCLUSIONS: This study suggests that a preoperative, single oral dose of prednisolone substantially reduced postendodontic pain. Further studies are needed to evaluate the applicability of these findings to other clinical conditions, single- versus multiple-visit endodontic treatment, and drug regimens.

The effect of post space preparation in teeth obturated with Mineral Trioxide Aggregate evaluated using a fluid filtration system.

The aim of this study was to evaluate the seal of a 4-mm Mineral Trioxide Aggregate (MTA) filling after post space preparation. Forty single-rooted premolar teeth without curved root anatomy and fractures were selected. The root length was standardized to 12 mm by removing excess from the apical end. The roots were instrumented to a 50 K-file by the step-back technique. The roots were randomly divided into groups A and B, of fifteen each. In group A, the canals were obturated with 7 mm of white MTA. After 24 h, 3 mm of MTA was removed to simulate post space preparation using a long shank diamond round bur. In group B, the canals were filled with 4 mm of white MTA. All samples were attached to a fluid filtration device. Measurements (µl min⁻¹ cm H2O⁻¹) were taken every 2 min, for 10 min and data were analyzed by an independent t-test (P > 0.05). Fluid transport averaged in groups A and B at 9.2 × 10⁻4, and 11.8 × 10⁻4 µl min⁻¹ cm H2O⁻¹, respectively. Independent t-test showed no significant difference between the groups (P < 0.05). Removing set MTA using a round bur for post space preparation does not affect its sealing ability, when 4 mm of MTA remains.