Basic And Clinical Study On Three Kinds Of Root Canal Filling Materials

Root canal therapy is a method of treating pulp necrosis and periapical diseases with the help of periapical tissues which are characterized by abundant blood flow and strong ability of repair and regeneration. It can eliminate the stimulation from root canal by following steps: preparation, disinfection and obturation of the root canal. Main purpose of the treatment is to cure the teeth with pulp necrosis or periapical diseases. The function of root canal filling, which is one of the major steps of root canal therapy, is to obturate the root canal that has been prepared and eliminate all portals of entry between the root canal and periodontium or oral cavity.Many studies at home and abroad have focused on Vitapex and heated gutta-percha in recent years, but only a few combined studies of basic and clinical investigation have been reported. Thus, the purpose of this study is to evaluate the performance and clinical short-term therapeutic effect of three root canal filling materials, including Vitapex + gutta-percha, zinc oxide-eugenol paste+ gutta-percha and Thermafil. The experiment was divided into three parts:1. In vitro study on microleakage of Vitapex + gutta-percha, zinc-5-oxide-eugenol paste* gutta-percha and ThermafilFreshly extracted fifty single-rooted human teeth were selected for this experiment and cut at the amelocemental junction using a diamond disk under water coolant. All roots were randomly divided into five groups of 10 roots each. The roots of three experimental groups were prepared and filled with zinc oxide-eugenol paste+ gutta-percha (Group A), Vitapex + gutta-percha (Group B) and Thermafil(Group C), respectively. 10 canals were prepared but not filled and remaining 10 canals were left untreated. Apical microleakage was evaluated with Indian Ink dye penetration. The results showed that mean depths of microleakage for group A, B and C were 3.36?.42mm, 2.09?.19mm and 1.05?.37mm respectively, there was significant difference between zinc oxide-eugenol paste+ gutta-percha group and Vitapex + gutta-percha or Thermafil group(P<0.05), and the sealing ability of Vitapex + gutta-percha and Thermafil was better than that of zinc oxide-eugenol paste+ gutta-percha. No significant difference between Vitapex + gutta-percha and Thermafil was found(P>0.05).2. Effect of removal of the smear layer on apical microleakage Freshly extracted sixty single-rooted human teeth were selected for this experiment and cut at the amelocemental junction using a diamond disk under water coolant. All roots were randomly divided into three groups of 20 roots each. The smear layers of 10 roots of each group were removed by 15% EDTA after the preparation. The roots of three groups were filled with zinc oxide-eugenol paste+ gutta-percha (Group A), Vitapex + gutta-percha (Group B)-6-and Thermafil(Group C), respectively. Apical microleakage was evaluated with Indian Ink dye penetration. The results showed that mean depths of microleakage in root canals with or without the smear layer in Group A, B and C were 3.36?.42mm, 3.42?.65mm, 2.09?.19mm, 1.70?.22mm 1.05?.37mm and 0.56?.11mm respectively. No significant difference was found between root canals with or without smear layer in all three groups (P>0.05) .It suggested that removal of the smear layer had no effect on the sealing ability of root canal materials.3. Clinical short-term therapeutic effect of Vitapex in root canal filling The purpose of this study was to compare the clinical short-term therapeutic effect of Vitapex with zinc oxide-eugenol paste+ gutta-percha in root canal filling. 161 teeth were randomly divided into two groups. The root canals of 82 teeth (Group A) were filled with zinc oxide-eugenol paste+ gutta percha, those of 79 teeth (Group B) were filled with Vitapex + gutta percha. The therapeutic effects were evaluated by follow-up of 3, 6 or 12 months. The results showed that efficiency rates of group A and group B were 80.3% , 93.1% (after 3 months), 82% , 95%( after 6 months), 81.3% , 89.4%( after 12 mont...