Inelastic deformation and microcracking process in human dentin

Abstract

Dentin is a mineralized collagen tissue with robust mechanical performance. Understanding the mechanical behavior of dentin and its relations to the dentinal structure can provides insight into the design strategies to achieve tooth functions. This study focuses on the inelastic deformation of human dentin and its underlying mechanisms. By combining four-point bending tests with fluorescent staining and laser scanning confocal microscopy, it was found that human dentin, especially root dentin, exhibited significant inelastic deformation and developed extensive microdamage in the form of microcracks prior to fracture. Dense and wavy microcracks spread uniformly across the tensile surface of root dentin, while compressive microcracks formed cross-hatched patterns. The presence of peritubular dentin in coronal dentin dramatically decreased the extent of microcracking, reducing inelasticity. Dentinal tubules were found to be initiation sites of both tensile and compressive microcracks. A unique crack propagation process was observed in root dentin under tension: numerous ring-shaped cracks formed at each dentinal tubule ahead of a growing crack tip. The advance of the tensile microcracks occurred by the merging of those ring-shaped cracks. The current findings on the microcracking process associated with inelastic deformation helps to understand the nature of strength and toughness in dentin, as well as the mechanical significance for structural variations across the whole tooth.

Compressive Residual Strains in Mineral Nanoparticles as a Possible Origin of Enhanced Crack Resistance in Human Tooth Dentin

“…A schematic representation of typical bending forces and stresses acting on teeth is also shown. The Supporting Information is available free of charge on the ACS Publications website at DOI: 10 …”

Accelerated fatigue testing of dentin-composite bond with continuously increasing load

“…However, nonlinear inelastic deformation had previously been observed in the vicinity of the loading and supporting points due to the high stress concentration there [32][33][34]. This has the effect of lowering the interfacial stress compared to that predicted by the linear elastic theory.…”

A New Method Combining Finite Element Analysis and Digital Image Correlation to Assess Macroscopic Mechanical Properties of Dentin

“…Two articles were chosen because they provide sample geometries and some results from three-point bending tests and four-point bending tests respectively [13,19]. The values from the published articles were recalculated using the classical beam theory (Sections 2.1.1 and 2.1.2).…”

“…Eltit et al [19] performed four-point bending tests on dentinal samples. They studied the maximum flexural stress of coronal and root dentin.…”

“…The differences in terms of maximum stress will be illustrated through the analysis of two articles [13,19]. …”