The Use of ESEM-EDX as an Innovative Tool to Analyze the Mineral Structure of Peri-Implant Human Bone.

Carlo Prati,Fausto Zamparini,Adriano Piattelli,Mauro Ferri,Maria Giovanna Gandolfi,Daichi Yonezawa,Daniele Botticelli

doi:10.3390/ma13071671

Abstract

This study aimed to investigate the mineralization and chemical composition of the bone–implant interface and peri-implant tissues on human histological samples using an environmental scanning electron microscope as well as energy-dispersive x-ray spectroscopy (ESEM-EDX) as an innovative method. Eight unloaded implants with marginal bone tissue were retrieved after four months from eight patients and were histologically processed and analyzed. Histological samples were observed under optical microscopy (OM) to identify the microarchitecture of the sample and bone morphology. Then, all samples were observed under ESEM-EDX from the coronal to the most apical portion of the implant at 500x magnification. A region of interest with bone tissue of size 750 × 500 microns was selected to correspond to the first coronal and the last apical thread (ROI). EDX microanalysis was used to assess the elemental composition of the bone tissue along the thread interface and the ROI. Atomic percentages of Ca, P, N, and Ti, and the Ca/N, P/N and Ca/P ratios were measured in the ROI. Four major bone mineralization areas were identified based on the different chemical composition and ratios of the ROI. Area 1: A well-defined area with low Ca/N, P/N, and Ca/P was identified as low-density bone. Area 2: A defined area with higher Ca/N, P/N, and Ca/P, identified as new bone tissue, or bone remodeling areas. Area 3: A well-defined area with high Ca/N, /P/N, and Ca/P ratios, identified as bone tissue or bone chips. Area 4: An area with high Ca/N, P/N, and Ca/P ratios, which was identified as mature old cortical bone. Bone Area 2 was the most represented area along the bone–implant interface, while Bone Area 4 was identified only at sites approximately 1.5 mm from the interface. All areas were identified around implant biopsies, creating a mosaic-shaped distribution with well-defined borders. ESEM-EDX in combination with OM allowed to perform a microchemical analysis and offered new important information on the organic and inorganic content of the bone tissue around implants.

Highlights

Oral bone remodeling processes close to the implant threads have become a topic of particular interest in modern implantology
Based on the tissues electron density grade detected by environmental scanning electron microscope (ESEM) investigation (Figures 1 and 2)
On the differences of Ca, P, and N atomic content detected by Energy-dispersive x-ray spectroscopy (EDX), four different bone areas were identified (Tables 1 and 2 and Figures 1 and 2) and grouped as follows: Area 1: Low mineralized area with major organic content

Summary

Introduction

Oral bone remodeling processes close to the implant threads have become a topic of particular interest in modern implantology. Stable peri-implant bone tissue is essential to achieving long-term results [1,2,3]. Bone is a dynamic tissue which is continuously modified in response to mechanical demands; these modifications lead to significant variations in the mineral and organic content [6]. These variations reflect the healing and the health conditions of bone [7]. An environmental scanning electron microscope (ESEM) is a repeatable investigation which is able to analyze mineralized tissue micromorphology without sample manipulation or deterioration [8,9], and may produce attractive results in the investigation of the peri-implant bone interface

Objectives

Methods

Results

Conclusion