The Effect of Whitlockite as an Osteoconductive Synthetic Bone Substitute Material in Animal Bony Defect Model.

Jeong-Kui Ku,Baek Hyun Kim,Pil-Young Yun,Il-Hyung Kim,Jung Hee Shim,Yu Ha Kim,Young-Kyun Kim

doi:10.3390/ma15051921

Abstract

This study aimed to evaluate the biomechanical properties in vitro and the bone regeneration of whitlockite (WH) compared with hydroxyapatite (HA) or β-tricalcium phosphate (β-TCP)-based material. We investigated the morphology and phase composition of the bone grafts using a scanning electron microscope and X-ray diffractometer patterns and tested the compressive strength. Four circular defects of 8 mm in diameter were created on the calvaria of twelve rabbits. One defect was left empty, and each of the other defects was filled with WH, HA, and β-TCP. At 4 and 8 weeks, the specimens were harvested to evaluate for the new bone formation and the remaining bone grafts. Regarding the biomechanical properties, the three grafts had a similar micropore size, and WH showed nanopores. The compressive strength of WH was higher than HA and β-TCP without statistical significance. The radiological and histomorphometric analyses demonstrated that the new bone formation was similar among the groups. The remaining bone graft of the WH group was greater than that of the HA and β-TCP groups at 4 weeks (p < 0.05), and the total bone area of the WH, HA, and β-TCP groups was greater than that of the other (p < 0.01). WH has excellent volumetric stability and osteoconductivity compared with HA and β-TCP.

Highlights

Autologous bone, which has osteogenesis, osteoinduction, and osteoconduction abilities, is still considered the gold standard bone graft treatment [1–3]
Bone tissue engineering has been researched for developing bone substitutes to overcome several disadvantages of autografts, such as extended healing time and the need for multiple surgeries
This study aimed to evaluate the biomechanical characteristics and bone healing outcomes of WH compared with HA and β-tricalcium phosphate (β-TCP) in the rabbit calvarial defect model

Summary

Introduction

Autologous bone, which has osteogenesis, osteoinduction, and osteoconduction abilities, is still considered the gold standard bone graft treatment [1–3]. Bone tissue engineering has been researched for developing bone substitutes to overcome several disadvantages of autografts, such as extended healing time and the need for multiple surgeries. Alloplastic bone substitutes, emulating the physicochemical properties of bone tissues, have been widely used because of their attractive advantages such as few donor site morbidity, little risk of transmission of infectious diseases, and sufficient supply [4]. The optimal bone substitutes possess biocompatibility with volumetric stability and allow cell infiltration for the remodeling process. The alloplastic bone substitutes have various osteoconductive capabilities depending on the manufacturing methods, crystal structure, size of pores, mechanical properties, composition, and absorption rate [5]. Synthetic calcium phosphate ceramics (hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP))

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