Influence of Post-Core and Crown Type on the Fracture Resistance of Incisors Submitted to Quasistatic Loading

Abstract

The aim of this paper was to evaluate the fracture resistance and failure type of maxillary incisor teeth, rebuilt with various types of post-core restorations and full crowns made of either direct conventional particulate filler composite (PFC, G-aenial Anterior, GC, Tokyo, Japan) or indirect CAD/CAM restorations (composite Cerasmart 270 and glass ceramic LiSi Block from GC). One hundred (n = 10/group) central incisors were cut and divided into 10 experimental groups restored with different approaches. In approach A, teeth were restored with a core build-up composite (Gradia Core, GC) for a core and full crown of PFC. Approach B had teeth restored using composite core and prefabricated fiber posts, and a complete crown of either PFC or CAD/CAM. Approach C contained teeth restored with a core of short fiber-reinforced composite (everX Flow, GC) and prefabricated fiber posts, and a complete crown of either PFC or CAD/CAM. In approach D, the teeth had a core of short fiber-reinforced composite only, and a complete crown of either PFC or CAD/CAM restorations. The root canals were prepared, and when posts were used, they were luted with either a dual-cure resin cement (LinkForce, GC) or everX Flow. As the control, sound teeth (n = 10) were used. Restorations were quasi-statically loaded until fracture. Failure type was visually investigated. The interface between the fiber post and luting cement was investigated using SEM, before and after completion of the loading test. The data were analyzed by analysis of variance (p = 0.05) followed by Tukey’s test. None of the restorative approaches restored the fracture load strength of intact teeth (p < 0.05). Restorations with additional fiber posts (Approaches B and C) had higher load-bearing capacity (p < 0.05) than restorations without fiber posts (Approaches A and D). Restorations that had short fiber-reinforced composite cores with or without fiber posts presented more repairable failures. Using short fiber-reinforced composite as post-luting and core build-up material with conventional fiber posts proved to be a promising method to strengthen severely damaged incisors.

Fabricated CAD/CAM Post-Core Using Glass Fiber-Reinforced Resin Shows Innovative Potential in Restoring Pulpless Teeth

“…Since bovine teeth frequently have enlarged root apexes that may affect their fracture resistance, teeth 30 months old with an apical size up to 1.3 mm were selected to obtain consistent results. The fracture load of TRINIA group had greater load bearing capacity compared with human central incisal restored by lithium silicate crown and short fiber-reinforced composite core [ 16 ] even under different experimental conditions. This suggests that the fiberglass woven into a mesh and layered structure of TRINIA is effective to reinforce pulpless teeth.…”

Stress distribution in restorations with glass fiber and polyetheretherketone intraradicular posts: An <i>in silico</i> analysis

“…Even though this type of prefabricated retainer (GFP) presents mechanical properties similar to those of dentin, it also has some limitations, such as its adaptability to wide canals, and its need for protocols to reduce adhesion failures, based on studies showing that GFPs may exhibit low bond strength between cement and retainer. For this reason, surface treatments, such as silanization, application of adhesives with 10-MDP, abrasive blasting or etching with acidic substances, and self-etching cements are needed to increase the tensile and shear strength at the interface between cement and retainer 3,5,13,22) .…”

Effect of Composite Core Materials on Fracture Resistance of Endodontically Treated Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies

“…Some unexplored aspects could have influenced the results of the present report. The presence of nanofillers in the polymeric composite resin or the restoration type could have an influence on mechanical properties and fracture strength; therefore, future studies could also take these variables into account [ 30 , 31 ]. Furthermore, resin composites specifically designed for core build-up are formulated with an increase in fillers for higher strength and easy manipulation, which could also affect the results [ 32 ].…”