Fluorine loss determination in bioactive glasses by laser‐induced breakdown spectroscopy (LIBS)

Abstract

Fluoride‐containing bioactive glasses and glass‐ceramics in the SiO2‐P2O5‐CaO‐CaF2 system are of great interest for dental applications, where the precipitation of fluorapatite supports tooth remineralization. Fluorine quantification in those glasses is key to estimate thermal properties and crystallization tendency. This work presents a study on fluorine determination by laser induced breakdown spectroscopy (LIBS) in four melt‐derived glass powders with varying P2O5 concentrations. LIBS enables fluorine quantification with a reduced analysis time, minimal to no sample preparation, and high spatial resolution. The fluorine calibration curve was obtained from CaF2 and SiO2 mixtures as reference samples, and the fluorine loss upon glass melting has been determined as a function of P2O5 content. The P2O5‐free glass shows the lowest fluorine loss (13%), with HF volatilization likely being responsible for the loss. By contrast, the glass with the highest P2O5 content (11.33 wt%) exhibits the largest fluorine loss (55%), owing to additional mechanisms involving the volatilization of phosphorus species like POF3.

Nano-imaging confirms improved apatite precipitation for high phosphate/silicate ratio bioactive glasses

“…Analysed fluoride contents have already been reported in our previous publication 19 , and phosphate/silicate ratio strongly influenced fluorine retention in the glass melts. The P 2 O 5 -free glass showed the lowest fluoride loss (13 ± 3%), which was associated with HF volatilization.…”

“…This difference we associated with an additional mechanism of fluoride loss in phosphate-containing compositions, involving the volatilization of phosphorus-containing fluoride compounds, e.g. POF 3 19 .…”

“…Glass P5 was only characterized as powder since it was not possible to obtain bulk pieces owing to its inherent devitrification tendency. Fluoride quantification was carried out by Laser-induced breakdown spectroscopy as detailed previously 19 .…”

Spectroscopic Properties of Inorganic Glasses Doped with Pr3+: A Comparative Study

“…The final composition of IZSBGL-Pr may be somewhat different from the nominal starting one due to fluorine losses during the melting process. Previously published works suggest that the fluorine losses could be quite large [48][49][50][51][52]. An another important factor that effectively quenched the luminescence is the concentration of OHgroups, which can be calculated from the transmittance spectrum.…”

Bioactive glass–ceramics containing fluorapatite, xonotlite, cuspidine and wollastonite form apatite faster than their corresponding glasses

“…The GC in this study, obtained from bioactive glasses in the system SiO 2 –CaO–P 2 O 5 –CaF 2 , vary in their phosphate/silicate ratio (PSR) but have a constant silicate network connectivity (NC) of 2.11 15 , 16 , same as the well-known Bioglass 45S5. Fluoride addition to glasses allows for the crystallisation of fluorapatite (FAp) during heat treatment 17 but also causes the pH rise upon immersion to be less pronounced 18 and potentially allows for an increased bone density in vivo due to the incorporation of fluoride into the bone apatite 19 , 20 .…”