Obturation Techniques Allow Microbial Leakage Unless Protected

Purpose To evaluate the quality of the apical 5‐mm seal produced by different filling techniques using a bacterial leakage model. Materials and Methods Sixty‐five extracted single‐rooted human teeth were decoronated, prepared, and instrumented. Roots were randomly divided into three experimental groups (15 roots each) and control groups (10 roots each). The apical 5 mm was filled with cold lateral condensation (CLC) technique, continuous wave of condensation (CWC), or injectable thermoplasticized gutta‐percha (Obtura II) using AH26 Plus as a sealer. Positive controls were filled with gutta‐percha without sealer, whereas negative controls were filled with a CLC technique and covered completely with two layers of nail varnish, including the orifice. A dual‐chamber leakage model using Enterococcus faecalis as a microbial marker was used for leakage evaluation. Bacterial penetration was monitored over a 60‐day period, and leakage was recorded when turbidity was observed in the lower chamber. Results All positive controls exhibited turbidity in the lower chamber within 24 hours. All negative controls demonstrated no bacterial leakage for the entire 60‐day observation period. The estimated mean day for leakage was 32 for CLC, 35 for CWC, and 30 days for Obtura II. Wilcoxon test showed no statistically significant difference (p = 0.98) in the survival time between the experimental groups. Conclusion The three filling techniques produced similar resistance to bacterial leakage when used to fill the apical 5‐mm segment of the canal while leaving the rest of the canal unfilled.