Table 1.
Comparison among the Sr-doped glass systems discussed in the section Sr-containing BGs: an overview.
| Glass system | Synthesis method/former oxide | The object of the study | Thermal and structural properties | Bioactivity tests | References |
|---|---|---|---|---|---|
| Na2O/K2O/MgO/CaO/B2O3 SiO2/P2O5/SrO | M/B | Controlled release of borate and Sr2+ ions for new bone formation | -No crystallization upon doping -No changes in the glass structure |
-Complete conversion to apatite -Controlled degradation and ion release below the cytotoxic level |
Li et al., 2016 |
| CaO/SrO/SiO2/MgO/P2O5 /CaF2 | M/S | Effect of Sr for Ca substitution on structural features, sintering behavior, and apatite-forming ability | - No changes in the glass structure - Wider PW up to 10 SrO mol% |
-Lower apatite-forming ability in SBF - Lower chemical degradation in TRIS-HCl -Ion release within therapeutically effective range |
Kargozar et al., 2016 |
| Na2O/SrO/SiO2/TiO2/CaO | M/S | Influence of Na+ and Sr2+ on solubility | - No changes in the glass structure - Higher Tg |
- Lower ion release rates | Ren et al., 2014 |
| B2O3/SrO/TiO2 B2O3/SrO/Na2O/TiO2 | M/B | Production of a borate glass system without the addition of other network formers; assessment of the physical, structural, thermal, and biological properties | -Higher Tg -Higher glass density |
- SrO content influences degradation rate and ion release -Sr concentration above cytotoxicity levels |
Yin et al., 2018 |
| CaO/SrO/SiO2/P2O5/Na2O | M/S | Influence of Sr for Ca substitution on physical properties | - No changes in the glass structure - Higher glass density - Lower oxygen density (network expansion) - Lower dilatometric softening point - Higher thermal expansion coefficient - Lower Tg |
_ | Baino et al., 2019 |
| CaO/ SrO-MgO/SiO2/Na2O K2O/P2O5 | M/S | Combination of the thermal behavior of Ca-rich silicate glasses with an improvement in biological results of MgO- and SrO-modified glasses | - Improved thermal stability - Improved mechanical properties |
- Strong apatite-forming ability | Jones et al., 2016 |
| CaO/SrO/SiO2/MgO/Na2O K2O/ZnO/P2O5 | M/S | Influence of Sr/Ca substitution on the sintering behavior | - Lower Tg - Higher Tc - Wider PW |
_ | Baino, 2017 |
| SiO2/CaO/SrO | SG/S | Development of Sr-delivering glasses | - No alterations in the mesoporous texture | - Enhanced bioactivity - Increased reaction kinetic |
Wei et al., 2014 |
| SiO2/CaO/MgO/SrO | SG/S | Synthesis, characterization, and investigation of the apatite-forming ability in SBF | - Crystalline phases (calcium and strontium silicates) | - Good apatite-forming ability - Apatite layer after 3-5 days immersion in SBF |
Fiume et al., 2018 |
| CaO/SrO/P2O5/Na2/CaO/SrO | M/P | Glass fiber production | - Higher thermal stability - Wider PW |
Reduced phosphate ions release - Formation of the apatite layer - SrO and MgO embedded in the apatite layer - Improved chemical stability |
Baino et al., 2018,a |
| P2O5/CaO/SrO/Na2O/MgO SrO | M/P | Investigation of phosphate glass formulation for controlled Sr release | - Lower Tg and Tm - Broadening of the main crystallization peak - No changes in the glass structure |
- Higher chemical durability - Lower dissolution rates |
Hench, 2006 |
| SiO2/P2O5/CaO/SrO | SG/S-P | Production and characterization of Sr-doped silico-phosphate glasses | - Higher Tp - Nucleation of new crystalline phases - Increase in the gel viscosity |
- Higher biodegradation rate | Hesaraki et al., 2010b |
M, Melt-quenching route; SG, Sol-gel route; S, Silicate glasses; B, Borate glasses; P, Phosphate glasses; PW, Processing Window; Tg, Glass transition temperature; Tc, Crystallization onset temperature; Tp, Maximum rate of crystallization temperature; Tm, Melting temperature; SBF, Simulated body fluid. All the results are referred to the doped system, compared to the undoped one. If the effect of SrO replacement for another oxide is specifically investigated, the oxide couple (e.g., SrO/CaO) is indicated in the column “Glass system.”