Abstract:

BACKGROUND: The vibration of high speed turbine handpiece during post space and post core preparation has an adverse effect on the continuous force of the bonding interfaces among the cement, dentin and post core, which influences the apical sealing effect of post core.
OBJECTIVE: To investigate the effects of post space and post core preparation at different time on apical microleakage with fiber posts system.
METHODS: Totally 55 extracted mandibular premolars each with single root canal were biomechanically prepared by using the step back technique. The samples were divided into five groups randomly: the immediate post space preparation group, 2 days after post space preparation group, 1 week after post space preparation group, a positive control group and a negative control group. Each group was averagely divided into three subgroups and they all were mixed for 15, 30 and 60 minutes on the cements, and then performed post core preparation. After that, all roots were dyed and transparentized. The dyeing scores of apical microleakage in each group were recorded under stereoscopic microscope observation.
RESULTS AND CONCLUSION: The score of apical microleakage in 1 week after post space preparation group was obviously higher than that in 2 days after post space preparation group. There were significant differences between the two groups (P < 0.05). No significant difference was shown for the microleakage of post core preparation after mixed for 15, 30 and 60 minutes on the cements (P > 0.05). These findings suggest that the immediate post space preparation can play a good protective effect on apical sealing. In terms of fiber posts, there are not effects of post core preparation at different time on apical microleakage after the same kind of cement solidified completely.