The Effect of Material Surface Microstructure on the Enhancement of Bone-Bonding Ability of a Hydroxyapatite-Implant by Low-Intensity Pulsed Ultrasound (LIPUS)

Masanori Kobayashi

doi:10.4236/msa.2021.121003

Abstract

Excellent firm bonding between the biomaterials and bone tissue (osseointegration and osteo-conductivity) has been desired for the stability in vivo of dental implants and artificial joints. Much has been learned about this concept, which has led to significant improvements in the design and surface modification of implants in the field of implant dentistry, orthopedic surgery. We have already reported that low-intensity pulsed ultrasound (LIPUS) irradiation can accelerate the bone bonding ability of the bio-conductive materials such as bioactive titanium and hydroxyapatite implant. However, it is still unclear whether the LIPUS could have same effect to different types of the bioactive-materials. Therefore, in this study, the differences of bone-like hydroxyapatite formation on some kind of hydroxyapatite surface in simulated body fluid (SBF) under the LIPUS irradiation were investigated. Two kinds of hydroxyapatite samples immersed in SBF was exposed to ultrasound waves, the bone-like apatite on the surface was analyzed by Scanning electron microscopy and X-ray diffraction. As a result, the enhancement of hydroxyapatite formation on the surface by LIPUS was confirmed, the initial epitaxial nucleation and crystal growth of apatite depended on crystal structure of the surface of matrix materials.

Highlights

Two kinds of hydroxyapatite samples immersed in simulated body fluid (SBF) was exposed to ultrasound waves, the bone-like apatite on the surface was analyzed by Scanning electron microscopy and X-ray diffraction
According to Kokubo, who developed SBF, the osseointegration of biomaterial was mainly due to mechanisms involving similar steps: firstly calcium phosphate precipitates and grows on the implant material surface as bone-like apatite, this apatite layer undergoes secondary progression in bonding to the bone tissue grown by biological mechanisms in vivo, and further biological bone modeling surrounding the implant follows
low-intensity pulsed ultrasound (LIPUS) therapy has been shown to enhance osteogenesis and is widely used as clinical treatment for complicated bone fractures in the field of orthopedic surgery, and it is often speculated that the enhancement of osseointegration of HA implants using LIPUS might be mainly due to bone ingrowth of bone tissue surrounding the implant

Summary

Introduction

M. Kobayashi replacement have been attributed to their firm bonding through direct contact between living bone and the surface of the load-carrying implant at the microappearance level, which is often recognized as an osseointegration or osteo-conductivity [1] [2]. More early bonding between a dental implant and the maxilla bone, or artificial joint stem and femoral bone will accelerate the onset of activity of patients sooner after an operation, with subsequent good long-term results. Approaches have been needed to accelerate osseointegration or bone bonding to HA material. Against this background, to enhance the direct attachment of implants with bone tissue, basic and clinical studies have tried [5] [6] [7]

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Discussion

Conclusion