Comparison of regional bond strength of post space of fiber-reinforced post luted with two types of cements at different testing times

الملخص EN

Back ground : This in vitro study was carried out to investigate the effect of post space regions (coronal, middle and apical), Time and the mode of polymerization (dual, self-cured) of the cements used on the bond strength between translucent fiber post and root dentin by using push-out test.

Materials and Methods : Forty eight extracted mandibular first premolars (single root) were instrumented with ProTaper Universal system files (for hand use) and obturated with gutta percha for ProTaper and AH26® root canal sealer following the manufacturer instructions, after 24 hours post space was prepared using FRC postec® plus drills no.3 ncreating 8 mm depth post space.

The prepared samples were randomly divided into two main groups (24 samples each) according to the used cement (Group M, self-cure, Multilink N) and (Group R, dual cure, Relyx U100).

Then each group was subdivided into three groups (each group contains 8 samples) according to the testing time after cementation.

(g M1 : push out test after 24 hour of cementation with Multilink N), (g M2 : push out test after one week of cementation with Multilink N),(g M3 : push out test after two weeks of cementation with Multilink N), (g R1 : push out test after 24 hours of cementation with Rely x U100), (g R2 : push-out test after one week of cementation with Rely x U100), (g R3 : push out test after two weeks of cementation with RelyxU100).

After cementation and incubation each root was sectioned horizontally into 3 slices (2 mm in thickness) represent the coronal, middle and apical regions of the post space.

Push out bond strength test was performed and measured using a universal testing machine (Tinius-Olsen) at across head speed of 0.5 mm/min.

Result : showed that regarding the root region, the bond strength values increased significantly apical to coronal increased with time for both tested cements.

For mode of polymerization, the self-cured resin cement Multilink N showed higher bond strength values.

Conclusion : the retention of fiber post was affected by root region, mode of polymerization of the cements used and time elapsed after cementation of the post.