Aim

To assess the mechanical properties of different types of intraradicular retainers using a tensile test and the failure types.

Materials and Methods

Sixty single-rooted mandibular premolars underwent endodontic treatment and were divided into three groups: The cast metal core (CMC) group, in which the CMC was cemented with zinc phosphate sealer; the CAD/CAM group, in which the fiberglass post was fabricated with the CAD/CAM system; and the prefabricated fiberglass post (PFP) group, in which a prefabricated fiberglass post was used. The latter two groups were cemented with Relyx® U200 resin sealer. Tensile strength tests were conducted on the specimens, followed by analysis under an microscope to determine failure types. The normality of tensile strength values was confirmed using the Shapiro–Wilk test. Group comparisons were made via one-way ANOVA with Tukey’s HSD post hoc test.

Results

The CMC group exhibited the highest mean tensile strength, followed by the CAD/CAM and PFP groups (p < .001). Predominantly post-localized failures occurred mainly in the PFP group, while cohesive root failures were observed only in the CMC group (p < .05). Adhesive failures at the sealer–dentin were more frequent in the CAD/CAM post group, whereas mixed failures (dentin/post) were noted in the CMC group (p < .05).

Conclusion

While cast metal core demonstrated superior strength, its use may lead to root cohesive failures. Understanding these mechanical behaviors and failure patterns can inform treatment strategies and minimize complications.

Search results

Tensile Strength in Root Dentin of Three Different Types of Intraradicular Retainers