Antibacterial Resin Composites with Sustained Chlorhexidine Release: One-Year In Vitro Study.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Adding chlorhexidine (CHX) to dental restorative materials offers a strategy to combat recurrent tooth decay.
• A key challenge is achieving sustained, long-term antimicrobial activity in these materials.

Purpose of the Study:

• To evaluate the impact of filler type and concentration on the chemical, physical, and antimicrobial properties of resin composites containing MMT/CHX.
• To assess the short- and long-term antimicrobial efficacy and chlorhexidine release kinetics.

Main Methods:

• Experimental composites were fabricated with varying filler concentrations (0-60%) and compositions (barium glass/colloidal silica ratios).
• Properties assessed included conversion, sorption, solubility, flexural strength, elastic modulus, CHX release, and antimicrobial activity against *Streptococcus mutans* via inhibition halo, biofilm growth, and CFU counts.
• Remineralization potential was evaluated using microhardness and CFU measurements.

Main Results:

• Filler concentration increased flexural strength and elastic modulus without affecting conversion, sorption, or solubility.
• Sustained CHX release was observed for up to 15 days; higher filler content reduced release rates.
• Composites with 60% filler (70% barium glass/30% silica) exhibited 12-month antimicrobial activity, significantly reducing CFU counts and inhibiting biofilm growth.

Conclusions:

• Dental composites containing 60% filler (70% barium glass/30% silica) and MMT/CHX demonstrate sustained antimicrobial efficacy for up to 12 months.
• This formulation also offers enhanced mechanical properties with comparable chemical and physical characteristics to control materials.