Calcium phosphate cements with strontium halides as radiopacifiers

Area of Science:

• Biomaterials Science
• Materials Chemistry
• Orthopedic Research

Background:

• Injectable implants require radiopacity for monitoring.
• Traditional radiopacifiers are unsuitable for resorbable cements due to low solubility.
• Strontium halides offer potential as water-soluble radiopacifiers.

Purpose of the Study:

• To compare radiopacity, mechanical properties, composition, and cytotoxicity of brushite cements with different strontium halides.
• To evaluate strontium fluoride (SrF2), strontium chloride (SrCl2·6H2O), strontium bromide (SrBr2), and strontium iodide (SrI2) as radiopacifiers.

Main Methods:

• Preparation of brushite cements with 10 wt% of various strontium halides.
• Assessment of radiopacity using X-ray imaging.
• Analysis of mechanical properties, crystal structure, and composition.
• In vitro cytotoxicity testing using Saos-2 cells.

Main Results:

• Cements with SrCl2·6H2O, SrBr2, or SrI2 showed radiopacity comparable to or exceeding commercial cements.
• Ionic strontium halides led to lattice expansion, indicating strontium substitution in the brushite structure.
• Strontium halides increased cement solubility and altered mechanical properties.
• No significant cytotoxicity was observed for cements containing SrCl2·6H2O, SrBr2, and SrI2.

Conclusions:

• Strontium chloride, bromide, and iodide are potential radiopacifiers for resorbable brushite cements.
• These compounds offer improved radiopacity without compromising early-stage cell viability.
• Further in vivo studies are needed to assess biocompatibility in injectable implants.