Evaluation of pigmented intraorifice barriers in endodontically treated teeth

The purpose of this study was to evaluate the effectiveness of three pigmen ted glass ionomer cements used as intraorifice barriers to prevent coronal microleakage. One hundred ten extracted mandibular human premolars were div ided into four experimental groups of 25 teeth each and two control groups of 5 teeth each. The experimental teeth were instrumented and obturated usi ng thermoplasticized gutta-percha and AH26 sealer. Group 1 teeth received n o further treatment. Teeth in groups 2 through 4 had 1 of 3 pigmented glass ionomers (Vitrebond, GC America, and Ketac-Bond) placed as an intraorifice barrier. Positive control teeth were instrumented but not obturated. The n egative control teeth were instrumented, obturated, and externally sealed w ith epoxy resin. The coronal 3 mm of each root was sealed into the lumen of an 18-mm segment of latex surgical tubing. After the apparatus was sterili zed, 2.0 mi of a 24 h growth of Proteus vulgaris in trypticase soy broth (T SB) was placed in the coronal reservoir of the tooth. The inoculated appara tus was placed into a presterilized test tube containing 1.5 mi of TSB and incubated for 90 days at 37 degrees C. The TSB in the lower reservoir was o bserved daily for turbidity, which would indicate leakage along the full le ngth of the obturated root canal. To determine if differences in microbial leakage occurred among the four experimental groups, Pearson's chi(2) and F isher's exact tests were performed. The confidence level was set at 95%. Th e positive and negative controls validated the microbial testing method. Th e teeth without an intraorifice barrier leaked significantly more than teet h with Vitrebond intraorifice barriers (p < 0.05). The difference in leakag e among the experimental glass ionomer barriers was not significant (p > 0. 05).