Characterization of polymethylmethacrylate microspheres loaded with silver and doxycycline for dental materials applications.

Objectives: The manufacturing of polymethylmethacrylate(PMMA) microspheres loaded with doxycycline(DOX) and/or silver sulfate(Ag2SO4) to be incorporated into glass ionomer cement(GIC).

Methods: PMMA microspheres were manufactured with Ag2SO4(1-5%) and/or DOX(5-15%). Particle size, encapsulation efficiency and drug release were measured by light microscope, ICP, and HPLC. Microspheres were added to a dental GIC(20%w/w). Drug release and DTS were investigated. Minimum inhibitory concentration and antibacterial effects of PMMA microspheres into GIC materials were tested.

Results: The median diameter of 50 µm was obtained for microspheres. DOX was encapsulated at an efficiency of 8.3% using a theoretical loading of 15%DOX + 5%Ag2SO4. The Ag2SO4 encapsulation efficiency was 0.63% using a theoretical loading of 5%AgSO4. All groups showed burst release within the first day and continued released up to 15 days, with 60-83% of DOX and approximately 30% of silver. For GIC, approximately 15% of DOX and 0.18% of silver were released in a 7-day period. Microbiological results showed an antimicrobial effect against S. mutans when the lead formulation of microspheres was added. The DTS was reduced by the inclusion of microspheres. Significance: PMMA microspheres containing DOX and Ag2SO4 offer a sustained antimicrobial activity for dental applications and promising potential for the biomedical field.