The Research On Mechanical Properties Of A New Type Of Quartz Fiber Post With Arc Angles

Purpose:The study was to investigate a new type of quartz fiber posts with arc angles of5°,10°,15°and evaluate the fracture resistance capacity after restoration. The failure mode of each restoration was also investigated.Method:In experiment1,four types of quartz fiber posts were selected. Normal straight quartz fiber post(Group A), quartz fiber post with arc angle of5°(Group B), quartz fiber post with arc angle of10°(Group C), quartz fiber post with arc angle of15°(Group D). Ten posts in each group were used to test the fracture resistance capacity. The three-point bending method of loading was applied. All kinds of fiber posts were observed by SEM. In experiment2, thirty-two extracted sound maxillary central incisor were randomly divided into4groups. The anatomic crowns were cut2mm coronal to the CEJ of the tooth. All the anterior teeth were treated endodontically. Group1was composed of teeth restored with the straight quartz fiber posts. Group2was composed of teeth restored with the quartz fiber posts with arc angle of5°. Group3was composed of teeth restored with the quartz fiber posts with arc angle of10°. Group4was composed of teeth restored with the quartz fiber posts with arc angle of15°. Standard Ni-Cr PFM crowns were cemented for all groups. A static load until failure was applied at a135degrees angle to the long axis of crown. Failure modes were visually examined.Result:In experiment1, ANOVA revealed that no significant difference of fracture resistance capacity among groups (F=0.195, P=0.899). Meanwhile, there is no significant (P>0.05) difference on load-bearing capacity among those three kinds of quartz fiber post with different arc angles(Group2,3and4). In experiment2, quartz fiber post with arc angles of5°.10°and15°had no significant (F=0.214, P=0.886>0.05) difference on fracture load of restorations compared with the normal quartz fiber post. Fisher’s precision probability test revealed no significant (P>0.05) difference of failure mode among all groups.Conclusion:The new type of quartz fiber posts with arc angles of5°、10°and15°demonstrated similar load bearing capacity with the normal quartz fiber posts. Furthermore, they provide better aesthetic restorations for inclined teeth.