muramidase and Dental-Leakage

The three methods of obturation assessed in this study were lateral condensation (80 teeth), Thermafil (40 teeth), and McSpadden (40 teeth). All teeth were prepared to the master apical file 30 and widened coronally by Gates Glidden burs before being randomly assigned to experimental groups to be filled by each technique; they were then sealed with nail polish, except for the apical 1 mm. Quantitative evaluation of apical microleakage for each technique was obtained after periods of 1 day, 7 days, 14 days, and 28 days of immersion in a lysozyme solution labeled with radioactive iodine by preparing horizontal sections of the teeth and measuring the level of radioactivity in each section using a gamma counter. Initial (1-day) leakage was least in the Thermafil group and was significantly different from the other techniques. Leakage was greatest in the laterally condensed samples. By the end of the study (28th day) values for lateral condensation were lowest, but were significantly different only for the McSpadden group. For all techniques leakage was most significant in the first 3 mm from the apex and was very low below this level so that all methods can be considered as giving a hermetic seal below 3 mm.

Topics: Analysis of Variance; Dental Leakage; Epoxy Resins; Gamma Cameras; Gutta-Percha; Humans; Immersion; Iodine Radioisotopes; Muramidase; Radiopharmaceuticals; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation; Statistics, Nonparametric; Time Factors; Tooth Apex

The aim of this in vitro study was to evaluate the apical seal obtained with three commonly used root canal sealing cements: Sealapex, AH Plus or Topseal, and Sealite, using a new method based on the quantitative analysis of 125I-radiolabeled lysozyme penetration. One hundred thirteen teeth with straight single root canals were instrumented to master apical point #25/30. These were divided into three groups: (i) negative control (4 roots) covered with two layers of nail polish, (ii) test group (105 roots) obturated by laterally condensed guttapercha with the three cements; and (iii) positive control (4 roots) obturated without cement. The groups were then immersed in 125I lysozyme solution for a period of 1, 7, 14, or 28 days. After removal, six sections of 0.8 mm length each were made of each root with a fine diamond wire. Each section was analyzed for activity by a gamma counter, corrected for decay, and used to quantify protein penetration. Leakage was high in the positive control and almost negligible in the negative control. AH Plus (Topseal) and Sealapex showed similar leakage behavior over time, with AH Plus (Topseal) performing better. Sealite showed acceptable leakage up until day 14, after which a large increase occurred, presumably due to three-dimensional instability.

Topics: Calcium Hydroxide; Dental Leakage; Epoxy Resins; Evaluation Studies as Topic; Humans; Iodine Radioisotopes; Muramidase; Root Canal Filling Materials; Salicylates; Zinc Oxide-Eugenol Cement