Push-Out Bond Strength of Endodontic Posts Cemented to Extracted Teeth: An In-Vitro Evaluation

Abstract

(1) Background: An ideal bond strength between endodontic posts and root canal dentin is essential for optimal retention and good prognosis. This study aimed to evaluate the push-out bond strength (PBS) of prefabricated fiber and metal posts, luted with resin cement to natural dentin. (2) Methods: Extracted premolars with similar root dimensions were assigned into two groups of 30 each for the metal and fiber posts. Teeth were mounted in acrylic blocks exposing 2 mm of the coronal root. Teeth were subjected to endodontic treatment and post-space preparations. Two groups were further subdivided into three sub-groups (n = 10) according to the size of the posts (# 4, 5 and 6). Posts were cemented with resin cement. Specimens were sectioned into 4 mm slices and subjected to the PBS test. (3) Results: The mean PBS was similar for the metal and fiber posts bonded with resin cement, showing a statistically significant result. An increase in post size increased the bond strength initially, but a further increase in size did not show any marked difference. A total of 71.66% of tested specimens failed with the adhesive failure mode. (4) Conclusions: Metal posts showed slightly higher retention compared to the fiber posts, although the p-value was similar for both types. An increase in the size of posts showed increased retention. The most common mode of failure was adhesive failure between cement and dentin.

Push-Out Bond Strength of Glass Fiber Endodontic Posts with Different Diameters

“…The Tukey post-hoc test with a 5% significance level showed a significant difference between the 1.0 mm-1.5 mm (p = 0.023) and 1.0-2.0 mm (p = 0.003) posts. Our study supports the findings of other authors: the bond strength of each post varies according to their diameter [19,20]. A study by Freitas and al.…”

“…Other factors contributing to the retention of posts are well studied [1,7,14,15]. However, a limited number of pieces of literature were found where the study focused on different diameters of the same post system [19][20][21] and root regions [22,26,31]. The effects of different diameters of posts and root regions still need to be researched more to make an adequately reliable conclusion.…”

Failure Analysis of Zirconia Versus PolyEtherEtherKetone Custom Made Posts in Endodontically Treated Anterior Teeth. (An In vitro Study)

“…Although there was no statistical significance between Zirconia and PEEK, within the zirconia group the failure modes were mostly cohesive in cervical and middle regions, followed by adhesive failure in the apical region and the least was adhesive cohesive failure also in the apical region. A possible explanation for the dominance of cohesive failure was stated by Habib et al (2022) 15 who mentioned that the type of cement, elastic modulus of post material, nature of prepared dentin and regions of stress concentration may increase chances of cohesive or mixed failures. This statement may explain the abundance of cohesive failures in zirconia's cervical and middle; furthermore, the high elastic modulus of zirconia transfers stress to regions with less modulus of elasticity as in cement and dentin hence increases the likelihood of these regions to fracture.…”

“…The elastic modulus is a determinant factor of stress distribution 15 . Materials with high elastic modulus like zirconia, distributes the forces towards the more flexible surrounding structure; thus, increasing the incidence of irreparable fractures 16 .…”