Fracture Strength and Failure Modes of Endodontically Treated Premolars Restored with Compact and Hollow Composite Posts Subjected to Cyclic Fatigue

Abstract

Physical and mechanical properties of continuous carbon or glass fiber reinforced endodontic posts are relevant to increase the retention and resistance of the tooth-restoration system. Hollow posts have been recently designed for delivering the luting cement through the post hole, thus enhancing the post-dentin interface by reducing the risk of air bubbles formation. Methods: Three type of endodontic posts, a carbon fiber hollow post, a glass fiber hollow post and a compact glass fiber post were investigated. Mechanical properties of these posts were assessed through bending tests. Teeth were subjected to fatigue cycling and the strength of restored teeth was detected through static tests. Failure modes were investigated through optical and scanning electron microscopy. Results show that composite posts increase the mechanical stability by more than 100% compared to premolars restored with particulate composite. Carbon fiber posts retain the highest strength (1467 N ± 304 N) among the investigated post and core restoration, but an unfavorable type of fracture has been observed, preventing the tooth re-treatment. Instead, more compliant posts (i.e., glass fiber reinforced composite, providing a strength of 1336 N ± 221 N), show a favorable mode of fracture that allows the re-treatment of teeth in the case that failure occurs. Glass fiber hollow posts show a good trade-off between strength and a favorable type of fracture.

Fracture resistance of resin endocrowns with and without fiber reinforced composite base material: A preliminary study

“…Post-core systems and full crown restorations are traditionally indicated during the restoration of ETT having excessive loss of dental tissue. 8,9 In recent years, fiberreinforced posts (FRPs) having the modulus of elasticity similar to that of dentin have been frequently used to increase the retention and resistance of the restoration after root canal treatment 54 Gallicchio et al 55 investigated fracture resistance and fracture patterns of three types of fiber posts used in restoring maxillary premolars subjected to similar fatigue cycling (1,000,000) and static tests of the current study. The mean fracture strength of both Lava and Cerasmart groups with and without Short FRC was lower than both sound teeth (1909) and fiber post-core restorations of Gallicchio's study.…”

Highly Reinforced Acrylic Resins for Hard Tissue Engineering and Their Suitability to Be Additively Manufactured through Nozzle-Based Photo-Printing

“…Stress vs. strain curves can be found in the Supplementary Files . The use of inorganic nanoparticles for increasing mechanical properties of restorative resins has gained great attention in the last decade, and compressive properties are of paramount importance because highly mineralized tissues in the oral cavity (i.e., dentin and bone) mainly undergo a compressive state of stress during mastication; crack initiation at restorative sites causes secondary caries [ 26 , 39 , 40 , 41 ].…”

“…In particular, highly reinforced photo-curing resins have gained great attention in the field of restorative dentistry. As a result, within more than half a century of dental material developments, novel micro- and nanoreinforced methacrylate is commercially available for restoring damaged dentin and enamel [ 24 , 25 , 26 ].…”

Assessment of Fracture Resistance of PEEK and Fibre Posts of the Endodontically Treated Teeth

“…The material of post-and-core should have mechanical and physical properties close to those of dentin so as to better tolerate the occlusal loads, preventing tooth fracture or de-bonding of the post. Referencing to previous studies, using post and core material with a decrease elastic modulus, fiber glass for example, resulted in more favourable stress distribution [3]. However, as fiber glass posts are available as ready-made material, they have limited usage to the shape of the root canal.…”