BACKGROUND: The post space cleaning using ultrasonic file can improve the bonding strength of fiber posts
cemented with the self-adhesive resin cement, but the effect on apical sealing ability is still unclear.
OBJECTIVE: To evaluate the effect of the post space cleaning using ultrasonic file on apical microleakage following treatment with two kinds of root canal sealers at two different residual lengths of root canal filling.
METHODS: Eighty extracted human maxillary anterior teeth with single-rooted canal were selected, and equivalently randomized into groups A and B (n=40 per group), followed by filled with Cortisomol or AH-plus, respectively. Groups A and B were randomly subdivided into four groups according to the residual length of root canal filling and with or without ultrasonic cleaning (n=10 per group): A1, B1 groups: residual 5 mm, no ultrasonic cleaning; A2, B2 groups: residual 5 mm, ultrasonic cleaning; A3, B3 groups: residual 3 mm, no ultrasonic cleaning; A4, B4 groups: residual 3 mm, ultrasonic cleaning. Subsequently, the apical microleakage was measured using dye method and transparent specimen technique under stereomicroscope.
RESULTS AND CONCLUSION: The apical microleakage of each group was as follows: A1 (0.73±0.21) mm, A2 (1.37±0.55) mm, A3 (1.18±0.36) mm, A4 (2.05±0.62) mm, B1 (0.34±0.18) mm, B2 (0.47±0.14) mm, B3 (0.59±0.23) mm, B4 (1.39±0.50) mm. The three-factor analysis of variance revealed that the ultrasonic cleaning, root canal sealers and residual length of root canal filling all had a significant effects on the apical microleakage (P < 0.05), and there were significant differences in the apical microleakage between groups A1 and A2, groups A3 and A4, groups B3 and B4, groups A2 and A4, groups B2 and B4 (P < 0.05). These results indicate that the ultrasonic cleaning increases the apical microleakage following the use of Cortisomol at 5 and 3 mm residual length, as well as the use of AH-Plus at 3 mm residual length. Moreover, for the same root canal sealer, the longer residual length of root canal filling indicates, the less microleakage after ultrasonic cleaning.