Jawbone remodeling: a conceptual study based on Synchrotron High-resolution Tomography

Giovanna Iezzi,Carlo Mangano,Adriano Piattelli,Luigi Baggi,Giuliana Tromba,Antonio Barone,Alessandra Giuliani,Federico Tirone

doi:10.1038/s41598-020-60718-8

Abstract

One of the most important aspects of bone remodeling is the constant turnover mainly driven by the mechanical loading stimulus. The remodeling process produces changes not only in the bone microarchitecture but also in the density distribution of the mineralized matrix - i.e. in calcium concentrations- and in the osteocyte lacunar network. Synchrotron radiation-based X-ray microtomography (microCT) has proven to be an efficient technique, capable to achieve the analysis of 3D bone architecture and of local mineralization at different hierarchical length scales, including the imaging of the lacuno-canalicular network. In the present study, we used microCT within a conceptual study of jawbone remodeling, demonstratively focusing the investigation in two critical contexts, namely in the peri-dental and the peri-implant tissues. The microCT analysis showed that a relevant inhomogeneity was clearly present in both peri-dental and peri-implant biopsies, not only in terms of microarchitecture and mineralization degree, but also considering the lacunar network, i.e. size and numerical density of the osteocyte lacunae. The correlated histological results obtained on the same samples confirmed these observations, also adding information related to non-mineralized tissues. Despite its demonstrative nature, it was concluded that the proposed method was powerful in studying jawbone remodeling because it revealed a direct correlation of its rate with the lacunar density, as achieved by the analysis of the osteocyte lacunar network, and an inverse correlation with the local bone mineral density, as revealed with the Roschger approach.

Highlights

One of the most important aspects of bone remodeling is the constant turnover mainly driven by the mechanical loading stimulus
One of the most important aspects of jawbone remodeling is the constant turnover mainly driven by the mechanical loading stimulus during mastication; this remodeling is evident in the alveolar bone[1,17,18,19]
For many years it has been hypothesized that the morphology of the lacuno-canalicular network (LCN) is related to the processes of mechanotransduction of osteocytes[21]

Summary

Introduction

One of the most important aspects of bone remodeling is the constant turnover mainly driven by the mechanical loading stimulus. The remodeling process produces changes in the bone microarchitecture and in the density distribution of the mineralized matrix - i.e. in calcium concentrations- and in the osteocyte lacunar network. Jawbone remodeling has been demonstrated to be a mechanism by which bone is able to prevent the accumulation of microdamages, with an extension of the bone fatigue parameters, determining an www.nature.com/scientificreports augmented biomechanical competence[18]. In this context, osteocyte activity was recently shown to be regulated by biological and by mechanical signals driven by the above-mentioned loading forces[20]. If these evidences will be definitely proved, the influence of the osteocyte network organization on bone remodeling processes would be crucial, determining three important consequences: the calcium regulation, the microdamage repair, and a mechanically adaptive control of bone architecture

Methods

Results

Conclusion