| Root canal therapy(RCT) is an essential method for treating various endodontic and periapical diseases. The success of the treatment depends majorly on the quality of canal preparation and the strictness of the canal filling. Root canal therapy for treating dental pulp necrosis and periapical diseases consists of root canal preparation, disinfection and filling in order to eliminate the stimulus source derived of the root canal. The canal preparation is an important step of RCT whose purpose lies in clearing the canal and taking shape to benefit the filling. The prepared canal where the dental pulp has been removed is filled in order to cut off the communication of the canal and periapical tissues, to prevent reinfection and to promote the healing of periapical lesions.At present, studies in this field mainly focus on Profile technique applied in root canal preparation and thermoplasticized gutta-percha technique applied in root canal filling. Up to date, however, little is studied about the combination of those two kinds of techniques. Therefore, this study aimed at getting a better understanding on the filling effect affected by different preparation methods and the medium and short-term clinical effect. The main contents and results of the study are presented as follows:1 The microleakage study on thermoplasticized gutta-percha technique applied in root canal filling60 freshly pulled out teeth were selected and resected at cemento-enamel junction. All specimens were divided randomly into 3 groups that each contained 20 teeth. The specimens in Group A were filled with thermoplasticized gutta-percha; The ones in Group B were filled with zinc oxide clove oil pastewith gutta-percha point and the ones in Group C were left unfilled. The lutation quality of the two root canal filling materials was contrasted after India Ink staining. The results showed that the length of staining line of the teeth in Group A was significantly shorter than that in Group B (P<0.001). The difference between those two groups and the control group was significant (P<0.001). These results suggested that the microleakage in the specimens in Group A filled with heated Gutta-percha by high temperature thermoplasticized injectable obturation was significantly smaller than that filled with zinc oxide clove oil paste with gutta-percha. In addition, the lutation quality of the former was superior to the latter.2 The microleakage study on thermoplasticized gutta-percha technique applied in root canal filling prepared with different methods40 lower first premolars after being pulled out and preserved were divided randomly into 4 groups which each contained 10 teeth. The root canals of specimens in Group A were prepared with routine method, the ones in Group B prepared with step by step method, the ones in Group C prepared with ultrasound technique and the ones in Group D prepared with Profile and ultrasound technique. During root canal preparation every canal was rinsed with 3% hydrogen peroxide solution and saline alternatively. The canals were filled by Obtura II system when prepared. The microleakage in every specimen was obtained by observation under stereomicroscope and the data were collected and analyzed with SPSS software. The results showed that the length of staining line of the teeth in Group D; was significantly shorter than those in the other groups. These results suggested that the microleakage was the smallest and the lutation quality was best in the specimens which prepared with Profile and ultrasound technique and filled with injectable obturation with thermoplasticized gutta-percha.3 Short-term curative effect of filling with thermoplasticized gutta-perchaIn order to observe the short-term curative effect of heated gutta-percha of the Obtura n system, 160 teeth were divided into 2 groups. After they were all prepared with Profile system, Group A was filled with heated Gutta-percha by injectable obturation and Group B was filled with zinc oxide-eugenol paste withgutta-percha. The patients were... |
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