Fracture resistance of thin wall endodontically treated teeth without ferrules restored with various techniques

Abstract

Objective To evaluate the fracture resistance and failure characteristics of simulated thin wall endodontically treated teeth without ferrules restored with various techniques. Materials and methods Forty‐eight human mandibular single‐root canal premolars were decoronated and endodontically treated. The 1 mm thick remaining root canal dentin was prepared. The roots were randomly divided into four groups of 12 roots according to the following post and core reconstruction techniques: direct resin composite post and core (CP), multiple fiber posts and resin composite core (FP), CAD/CAM anatomical post and core (AP), and metal cast post and core (MP). Full metal crowns were cemented to the cores. All specimens were subjected to thermocycling for 5000 cycles and submitted to axial compression until failure at a 45°angle using a universal testing machine. The failures were classified into one of the followings: post and/or core fractures, root fractures, and root fractures combined with post and/or core fractures. Results Average failure loads of groups CP, FP, AP, and MP were 360.0, 655.2, 402.7, and 856.1 N, respectively. MP provided the highest failure load, which was significantly higher than those of the other groups (p < 0.05). FP was second, being inferior to MP with a significance level of p = 0.039. CP exhibited the least failure load, and it was not significantly different from the AP group (p > 0.05). Root fractures were the major failure mode for most of the specimens except the CP group, in which composite fractures at the cervical level were commonly observed. Conclusion Metal cast post and core provided the highest fracture resistance for reconstruction of a thin wall in endodontically treated teeth without ferrules, followed by multiple fiber posts and resin composite core. The milled anatomical post and core and a direct resin composite post and core provided significantly lower fracture resistance. Clinical significance Metal cast posts and core and multiple fiber posts with resin composite core techniques were effective for restoring severely compromised endodontically treated teeth.

Can the Remaining Coronal Tooth Structure Influence the Mechanical Behavior of Nonpost Full Crowns?

“…In 2018, a systematic review by Nauman et al reported that in clinical situations where there are no remaining coronal structures, no consensus or definitive finding supports or rejects the use of posts. 7 However, an in vitro study by Iemsaengchairat and Aksornmuang 38 demonstrated that in the cases where ETT have thin remaining root walls and a complete absence of a ferrule, cast metal posts and cores provided the highest fracture resistance, followed by multiple fiber posts and composite resin cores.…”

Restorative Modalities for Structurally Compromised Teeth with Thin-walled Roots: A Literature Review

“…Also, multiple fiber post technique in comparison to a single FRC posts has shown better results. 6 21…”

“…Also, multiple fiber post technique in comparison to a single FRC posts has shown better results. 6,21 Post diameter has a great influence on post stiffness, but its effect on fracture resistance is yet to be researched. According to some studies, posts with larger diameters are recommended since they have demonstrated higher resistance than less diameter posts, but this is not as important as saving the tooth structure.…”

“…In some of them, optimal treatments with suitable techniques have been proposed; however, the long-term success of those treatments is not determined yet. 5 6 In ETT, posts are placed to improve fracture resistance and the maintenance of coronal restorative treatments. 7 In current restorative approaches, post and core systems are gradually developing toward being more corrosion resistant and stronger, and less invasive techniques that do not weaken the remaining root structure are recommended due to the likeliness of flared canals to fracture.…”

The Use of Polyetheretherketone (PEEK) as an Alternative Post and Core Material: Five-Year Follow-Up Report

“…Stiff materials can promote high stress concentrations in the post surface but will deflect less during loading, which can be better to support the coronal restorations. However, this can result in catastrophic fractures of roots in weakened areas if overloaded with occlusal forces [ 15 , 16 , 17 ]. In clinical protocols, some materials were tested to prevent the catastrophic fractures of endodontically treated teeth [ 18 , 19 ].…”