Poster N10 - Adapting the Degradability rate of Bioactive Glass to Fit Varied Clinical Settings and Patient ages

Introduction: Purpose/

Objectives:
Bioactive glass (BaG) is an appealing material due to its ability to enhance bone formation, making it attractive for use in dentistry and bone surgery. The controllability of BaG implant dissolution has become an important objective in addressing variations in healing rates seen in different regions of the skeleton and different age groups. To achieve this, modification of the composition (fluorine and boron content) of the BaG was explored.

Materials and

Methods: Material and Method/ Methodology:
To investigate the fluorine (CaF2) and boron (B2O3) incorporation influence in the BaG network and to validate the fabrication protocol, a reference composition of BaG was adopted. CaF2 and B2O3 were introduced to the quaternary BaG system SiO2-Na2O-CaO-P2O5 in concentrations ranging from 5 to 20 wt.% to fabricate fluorine bioactive glass (BaG-F) and boron bioactive glass (BaG-B). Either CaF2 or B2O3 was mixed with sodium metasilicate pentahydrate (Na2SiO3 5H2O), calcium metasilicate (CaSiO3), sodium metaphosphate (Na3P3O9), and calcium carbonate (CaCO3), and heated the mixture at 1300oC. The molten vitreous material was then tempered in preheated molds and annealed for 4 h at a temperature near that of its glass transition temperature (Tg). Degradation was investigated by immersing BaG samples in simulated body fluid (SBF). X-ray powder diffraction (XRD) technique was used to identify the obtained biomaterials phase. Infrared spectroscopy (FTIR) and differential thermal analysis (DTA) were applied to prove fluorine or boron insertion in the BaG structure. The bioactivity of produced BaGs was checked using an inductively coupled plasma-optical emission spectrometer (ICP-OES). Scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) techniques were employed to assess the biomaterial resorbability.

Results, Conclusions, and Discussions: The fabrication of BaG with a high fluorine content of up to 20 wt.%, which was previously unattainable was successfully achieved in this study using the melting method. Additionally, the structural stability of produced constructs was attained by increasing the fluorine content, leading to a slowed degradation rate in SBF. It was also found that by increasing boron concentration up to 20 wt.% in BaG-B, crystallization rate and the quality of the newly formed hydroxyapatite (HAp) layer on the surface of BaG-B was improved. The presence of boron also enhanced the degradation of BaGs in SBF. Previous attempts by other groups faced challenges, including the fabrication technique employed, resulting in limited success.
Conclusion/Significance:
It is possible to slow down BaG degradation rate by increasing its fluorine content and accelerate its degradation by increasing its boron content. Produced BaG with high boron content can be suitable for use in children and the upper limb, while that with high fluorine content can be applied for treating older patients and in the lower limb. Our next step involves evaluating the performance of these materials in vivo.

Acknowledgements (Optional):