Methods: The root canals of 96 human intact single-rooted extracted teeth were obturated with gutta-percha using lateral condensation. Roots were restored with one of the following dowel systems according to the manufacturer's instructions: Parapost (SSD), Ribbond (RSPFD), Cosmopost (ZD), Superpost (GFD). Two different resin cements (Multilink automix and Clearfil Esthetic cement) were used in cementation procedure. Using the computerized fluid filtration method, microleakage of the specimens along the dowel space and root canal restorative material was measured at 1 week, and 6 months following dowel insertion. A repeated-measures analysis of variance (ANOVA) was used to analyze logarithmic transformations of data (time and dowel material) for significant differences. Tukey HSD test and paired t tests were used to perform multiple comparisons (p=0.05).
Results: The data indicated that the microleakage values varied according to the dowel system and luting cement used (p<0.05). The initial microleakage measurement in Parapost was similar with the other dowel systems, but became significantly different at 6 months (P<0.05). The microleakage of Parapost increased over time (P<0.05), but microleakage of Ribbond, Cosmopost and Superpost dowels remained constant (P>0.05). The statistical microleakage values for Multilink Automix cement were higher than Clearfil Esthetic cement (P<0.05) for all the dowel system groups.
Conclusions: Resin-supported polyethylene fiber, glass fiber and zirconia dowels tested exhibited less microleakage compared to stainless steel dowel system. Multilink Automix cement showed higher microleakage than Clearfil Esthetic cement .