The Difference of Structural State and Deformation Behavior between Teenage and Mature Human Dentin

Abstract

Objective. The cause of considerable elasticity and plasticity of human dentin is discussed in the relationship with its microstructure. Methods. Structural state of teenage and mature human dentin is examined by using XRD and TEM techniques, and their deformation behavior under compression is studied as well. Result. XRD study has shown that crystallographic type of calcium hydroxyapatite in human dentin (calcium hydrogen phosphate hydroxide Ca9HPO4(PO4)5OH; Space Group P63/m (176); a = 9,441 A; c = 6,881 A; c/a = 0,729; Crystallite (Scherrer) 200 A) is the same for these age groups. In both cases, dentin matrix is X-ray amorphous. According to TEM examination, there are amorphous and ultrafine grain phases in teenage and mature dentin. Mature dentin is stronger on about 20% than teenage dentin, while teenage dentin is more elastic on about 20% but is less plastic on about 15% than mature dentin. Conclusion. The amorphous phase is dominant in teenage dentin, whereas the ultrafine grain phase becomes dominant in mature dentin. Mechanical properties of human dentin under compression depend on its structural state, too.

The mechanical properties of human dentin for 3-D finite element modeling – numerical and analytical evaluation

“…Panfilov et al showed higher tensile strength of mature rather than teenage dentin (549.5 ± 26.9 MPa vs 445.2 ± 30.9 MPa, respectively). 28 Within the limitations of this study we can suggest the transversely isotropic behavior of dentin and the anisotropy ranged from 6.9 to 35.2%, depending on the dentin location. The numerical and analytical dentin homogenization presented similar results.…”

Horizontal root fractures in posterior teeth without dental trauma: tooth/root distribution and clinical characteristics

“…, Panfilov et al . ) and the effect of long‐term occlusal force during mastication that acted as a risk factor for root fracture (Chan et al . , Lin et al .…”

“…In addition, based on a comparison of the clinical characteristics between HRF and VRF in posterior teeth, VRF in endodontically treated teeth were encountered most commonly in patients between 40 and 60 years old (Testori et al 1993, Chan et al 1999, Tsai et al 2001, whereas VRF in nonendodontically treated teeth and HRF (the majorities of teeth were nonendodontically treated) had an older age distribution (Yang et al 1995, Chan et al 1999, Wang et al 2011. Previous studies have suggested that increasing age may result in structural changes within the tooth such as alteration in dentine elasticity (Xu et al 2014, Panfilov et al 2016) and the effect of longterm occlusal force during mastication that acted as a risk factor for root fracture (Chan et al 1999, Lin et al 2008. Whether the age-related structural change or long-term usage of teeth resulted in HRF in posterior teeth is unclear and needs to be investigated in further studies.…”

Influence of elastic modulus of intraradicular posts on the fracture load of roots restored with full crowns

“…In this study we attempted to eliminate some of the variables which are inevitably present in in vitro studies evaluating the mechanical behavior of pulpless teeth. Human teeth, even within a certain range of acceptability, present inherent variations in size and morphology and may behave differently under mechanical loads due to chemical-physical differences, amorphous phase content and elastic modulus 11 . The use of identical resin replicas constructed from only one dental element with the same external and intracanal morphology were used to standardize the roots dimensions and ensure specimens uniformity.…”