Objectives: Aim of study was to evaluate ability of intra-orifice sealing materials to reduce leakage of root-fillings via exposed cervical tubules.
Methods: 104 single-rooted mandibular premolars were instrumented and obturated with gutta-percha to the CEJ. Teeth were divided into five groups of 20 teeth, plus controls. The first group had no orifice-seal. In remaining groups, coronal 3 mm of root-filling was removed and sealed with either zinc phosphate, zinc polycarboxylate, glass ionomer cement or amalgam. Cervical dentinal tubules were exposed by applying citric acid on labial and lingual surfaces. Remaining root surface was varnished before exposure to methylene blue for 48 hours. Teeth were cleared and dye penetration was measured using operating-microscope. Comparisons were made with the first group as a reference, using repeated measurement test with Dunnett correction. Comparisons amongst other experimental groups were made using repeated measurement test with Bonferroni correction.
Results: Dye readily penetrated the canal from exposed cervical tubules. Significantly greater leakage (p < 0.001) occurred in the control group without a seal, compared to other groups. GIC intra-orifice seal resulted in significantly less leakage (p < 0.001) than the other three materials.
Conclusion: Exposed dentinal tubules serve as a pathway by which cervical leakage can occur. With an intra-orifice sealing material, however, leakage is shown to be significantly reduced. GIC was the most effective intra-orifice sealing material to minimize leakage.