Incorporating Germanium Oxide into the Glass Phase of Novel Zinc/Magnesium-Based GPCs Designed for Bone Void Filling: Evaluating Their Physical and Mechanical Properties

Basel Khader,Omar Rodriguez,Mark Towler

doi:10.3390/jfb9030047

Basel Khader, Omar Rodriguez + Show 1 more

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https://doi.org/10.3390/jfb9030047

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Abstract

The structural role of Germanium (Ge), when substituting for Zinc (Zn) up to 8 mol % in the 0.48SiO2–0.12CaO–0.36ZnO–0.04MgO glass series, was investigated with respect to both the glass chemistry and also the properties of glass polyalkenoate cements (GPCs) manufactured from them. The Network connectivity (NC) of the glass was calculated to increase from 1.83 to 2.42 with the addition of GeO2 (0–8 mol %). Differential thermal analysis (DTA) results confirmed an increase in the glass transition temperature (Tg) of the glass series with GeO2 content. X-ray photoelectron spectroscopy (XPS) showed an increase in the ratio of bridging oxygens (BO) to non-bridging oxygens (NBO) with the addition of GeO2, supporting the NC and DTA results. 29Si magic angle spinning nuclear magnetic resonance spectroscopy (29Si MAS-NMR) determined a chemical shift from −80.3 to −83.7 ppm as the GeO2 concentration increased. These ionomeric glasses were subsequently used as the basic components in a series of GPCs by mixing them with aqueous polyacrylic acid (PAA). The handling properties of the GPCs resulting were evaluated with respect to the increasing concentration of GeO2 in the glass phase. It was found that the working times of these GPCs increased from 3 to 15 min, while their setting times increased from 4 to 18 min, facilitating the injectability of the Zn/Mg-GPCs through a 16-gauge needle. These Ge-Zn/Mg-GPCs were found to be injectable up to 96% within 12 min. Zn/Mg-GPCs containing GeO2 show promise as injectable cements for use in bone void filling.

Highlights

Fractures of the wrist can be common at any age, but individuals suffering from osteoporosis are at a greater risk [1]
The most common wrist fractures are those of the distal radius and scaphoid
The objective of this study was to investigate the incorporation of Ge into the glass phase of a novel Zn/Mg-glass polyalkenoate cements (GPCs) glass composition (0.48SiO2, 0.36ZnO, 0.12CaO, and 0.04MgO), with respect to the influence that the glass changes had on the handling properties of Zn/Mg-GPCs manufactured from them

Summary

Introduction

Fractures of the wrist can be common at any age, but individuals suffering from osteoporosis are at a greater risk [1]. There has been a rise in both internal and external fixation of fractures regarding the distal radius and scaphoid as a result of increased patient expectation and the implementation of improved fixation techniques [2]. Calcium phosphate cements (CPCs) (Norian SRS; Norian, Cupertino, California) and Cortoss (Stryker, MI, USA) have been used as bio-adhesives for treating wrist fractures. It has been reported in the literature that CPCs are biocompatible and osteoconductive; they often provide insufficient stability without the use of pins and k-wires [4]. Cortoss has been reported to offer sufficient strength and bonding to aid in the healing and reconstruction of the fractured bone, it has been found to cause exothermic reactions during setting, resulting in thermal necrosis of healthy bone tissue [5]

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