BACTERIAL LEAKAGE OF MINERAL TRIOXIDE AGGREGATE AS A ROOT-END FILLINGMATERIAL

Previous dye leakage studies have shown that mineral trioxide aggregat e leaks significantly less than other commonly used root-end filling m aterials. This study determined the time needed for Staphylococcus epi dermidis to penetrate a 3-mm thickness of amalgam, Super-EBA, Intermed iate Restorative Material (IRM), or mineral trioxide aggregate (MTA) a s root-end filling materials. Fifty-six single-rooted extracted human teeth were cleaned and shaped using a step-back technique. Following r oot-end resection, 48 root-end cavities were filled with amalgam, Supe r-ERA, IRM, or MTA. Four root-end cavities were filled with thermoplas ticized gutta-percha without a root canal sealer (+ control), and anot her four were filled with sticky wax covered with two layers of nail p olish (- control). After attaching the teeth to plastic caps of 12-ml plastic vials and placing the root ends into phenol red broth, the set -ups were sterilized overnight with ethylene dioxide gas. A tenth of a microliter of broth containing S. epidermidis was placed into the roo t canal of 46 teeth (40 experimental, 3 positive, and 3 negative contr ol groups). In addition, the root canals of two teeth with test root-e nd filling materials and one tooth from the positive and negative cont rol groups were filled with sterile saline. The number of days require d for the test bacteria to penetrate various root-end filling material s was determined. Most samples whose apical 3 mm were filled with amal gam, Super-EBA, or IRM began leaking at 6 to 57 days. In contrast, the majority of samples whose root ends were filled with MTA did not show any leakage throughout the experimental period (90 days) in this stud y. Statistical analysis of the data showed no significant difference b etween the leakage of amalgam, Super-EBA, and IRM. However, MTA leaked significantly less than other root-end filling materials maintained u nder test conditions for 90 days in this experiment (p < 0.05).