Stress–strain response in human dentine: rethinking fracture predilection in postcore restored teeth

Abstract

In this study, the biomechanical perspective of fracture predilection in post-core restored teeth is investigated using computational, experimental, and fractographic analyses. The computational finite element analysis and the experimental tensile testing are used to evaluate the stress-strain response in structural dentine. The fractographic evaluations are conducted using laser scanning confocal microscopy and scanning electron microscopy to examine the topography of dentine from experimentally fractured specimens, and clinically fractured post-core restored teeth specimens. These experiments aided in correlating the stress-strain response in structural dentine with cracks and catastrophic fractures in post-core restored teeth. It was observed from these experiments that the inner dentine displayed distinctly high strains (deformations), while the outer dentine demonstrated high stresses during tensile loading. This implies that the energy fed into the material as it is extended will be spread throughout the inner dentine, and there is less possibility of local increase in stress at the outer dentine, which can lead to the failure of dentine structure. During post-endodontic restoration with increase in loss of inner dentine, the fracture resistance factor contributed by the inner dentine is compromised, and this in turn predisposes the tooth to catastrophic fracture.

Impacts of Conservative Endodontic Cavity on Root Canal Instrumentation Efficacy and Resistance to Fracture Assessed in Incisors, Premolars, and Molars

“…Regions of stress-strain concentration are interpreted as potentiators of crack initiation and propagation (122). This method lends itself to simulation of different loads applied to the tooth structure, both static and dynamic, as well as different types of restorations present.…”

Fracture resistance of endodontically treated teeth restored with a bulkfill flowable material and a resin composite

“…Different studies have shown that the preparation of endodontic access cavities reduces the strength of the teeth, because of deep and extended cavity preparations which critically reduce the amount of dentin (4)(5)(6)(7)(8) and increase cuspal deflection during function (9). The importance of conserving the bulk of dentin was demonstrated in maintaining the structural integrity and in the prognosis of endodontically restored teeth (10)(11)(12)(13), as the fracture resistance and stress distribution of endodontically treated teeth is directly affected by the amount of residual coronal dentin (4,(14)(15)(16)(17)(18). In posterior preparations, especially when the cervical margin is located in dentin, the polymerization shrinkage effects can be significant, producing marginal defects and gaps despite careful application (19).…”

Effect of periodontal disease on the bond strength of fiber post cemented with different adhesive systems and resin luting agents

“…Endodontically-treated teeth present different responses to mechanical loads from intact teeth. The removal of pulp and root dentin diminishes a protective feedback mechanism and reduces the stress-strain capacity of the teeth, compromising the root fracture resistance [4,28]. The stability of the teeth is reduced by endodontic preparative procedures, leading to more root deformations and less stiffness [29,30].…”