ABSTRACT
Objective: the aim of this study was to assess the effect of condensation pressure on microleakage of mineral trioxide aggregate [MTA]
Methods: this in vitro experimental study was conducted on 55 sound single-rooted straight-canal extracted human teeth. The teeth were sectioned at the cementoenamel junction [CEJ] and at 3 mm above the root apex. The roots were mounted in putty. Samples were then divided into three experimental groups [n=15] and positive and negative control groups [n=5]. After filing of the root canals to file #50, white ProRoot MTA paste was prepared according to the manufacturer's instruction and applied to the canals using condensation pressure of 0.44, 3.22 and 8.88 Mpa in groups one to three, respectively. After a 48-hour setting time, each root was connected to the fluid filtration system to measure microleakage. The mean microleakage rate of the groups was calculated and compared using one-way ANOVA and least significant difference test
Results: the mean microleakage with condensation pressure of 0.44, 3.22 and 8.88 MPa was 1.70×10[-4], 1.17×10[-4] and 0.48×10[-4] microL/minute, respectively. One-way ANOVA showed that the mean microleakage rate was significantly different among the groups [P<0.05]. The lowest microleakage was observed in condensation pressure of 8.88 MPa
Conclusion: within the limitations of this study, the results showed that increase in condensation pressure decreased the rate of microleakage
ABSTRACT
Radiographic usage for determination of working length is difficult in children, because of hazardous irradiation, superimposition of the permanent tooth germ and primary tooth root, mouth opening limitation, lack of cooperation, and radiographic misinterpretation of primary teeth. The purpose of this clinical study was to evaluate the accuracy of the Raypex 5 apex locator for root canal length determination in primary teeth. This experimental study used 23 primary second molar teeth that were scheduled for extraction. Following access cavity preparation, the working length was determined with a Raypex5 electronic apex locator. The teeth were extracted and real lengths of root canals were measured with insertion of a K-type file into each canal until it emerged at the apical foramen. This length, minus 0.5 mm, was recorded as the real root canal length. The data were statistically analyzed using a One Sample /-test. The accuracy of the Raypex 5 electronic apex locator in determining working length within 0.5 mm of the real length was 81.2% and 100% within 1mm of the real length. This study concluded that the Raypex 5 apex locator is a useful tool for measuring root canal lengths in primary teeth