Post retentive ability of a new resin composite with low stress behaviour

To assess by means of push-out test the post retentive potential of a new flowable resin composite with low polymerization stress.

SureFil(®) SDR™ (Dentsply, S) was compared with the resin cement Calibra (Dentsply, C). S and C were used in combination with the adhesive XP Bond (Dentsply, XPB). In C group the Self-Cure Activator was mixed with XPB. The following types of fibre posts were luted into 30 extracted premolars: Radix Fiber Post (Dentsply, R), DT Light Post (RTD, LP), ER Dentin Post (Komet, ER), DT Light SL (VDW, SL), FibreKleer (Jeneric Pentron, F). Six posted roots per group were tested. Each root provided three to five 1mm-thick slices. Measured push-out strengths were differentiated by post space level and statistically analysed (p<0.05). The failure mode of each debonded specimen was assessed.

Cement type did not have a significant effect on post retention (p=0.54). Post type was a significant factor for push-out strength (p<0.001). LP exhibited significantly higher retentive strength than SL and F; push-out strengths of ER and R were significantly higher than those of F. Post retention was significantly influenced by post space level (p<0.001). Significantly higher push-out strengths were recorded at the coronal third than at the middle and apical levels. The post-cement interaction was significant (p=0.002). Posts luted with S most often failed at the cement-post interface.

When the new flowable low-stress composite was used to lute fibre posts, similar retentive strengths to those of a marketed cement from the same manufacturer were achieved.

SureFil(®) SDR™, a flowable composite originally proposed for bulk filling of posterior restorations, exhibited post retentive strengths similar to those of a cement by the same manufacturer. With a relatively high filler load, yet a low curing stress, SureFil(®) SDR™ may be adequate for both post cementation and core build-up.