Chlorhexidine-releasing methacrylate dental composite materials

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Dental composites are prone to bacterial adhesion and microleakage, compromising restoration longevity.
• Incorporating antibacterial agents into dental composites is a strategy to improve oral health outcomes.
• Current dental materials may not fully prevent secondary caries or material degradation due to bacterial activity.

Purpose of the Study:

• To develop and evaluate light-curable dental composites with enhanced antibacterial properties.
• To investigate the effect of varying chlorhexidine diacetate (CHXA) concentrations within methacrylate monomers on material performance.
• To assess the efficacy of these experimental composites in inhibiting biofilm formation and microleakage compared to commercial dental materials.

Main Methods:

• Production of light-curable composites using strontium fluoroaluminosilicate glass and methacrylate monomers with varying ratios of hydroxyethylmethacrylate (HEMA) and chlorhexidine diacetate (CHXA).
• Evaluation of light cure polymerization rates and water sorption characteristics.
• Assessment of CHXA release kinetics from set materials.
• Biofilm growth inhibition studies using a constant depth film fermentor (CDFF) with experimental composites, commercial composite Z250, and glass ionomer cements (Fuji II LC, Fuji IX).
• Microleakage evaluation using excavated bovine dentine cylinders restored with experimental and commercial materials.

Main Results:

• Increasing HEMA content in the monomer formulation decreased light cure polymerization rates but increased water sorption and CHXA diffusion-controlled release.
• Experimental composites with 50 and 90 wt% CHXA/HEMA solution exhibited slower biofilm growth rates on their surfaces compared to Z250, Fuji II LC, and Fuji IX cements.
• Bacterial microleakage into the gap between restored dentine and material was significantly reduced with the 50 wt% HEMA/CHXA formulation.
• Both polymer and bacterial microleakage were completely prevented with the 90 wt% HEMA/CHXA formulation, attributed to swelling compensation and antibacterial release.

Conclusions:

• Light-curable dental composites containing CHXA in HEMA demonstrate significant potential for reducing bacterial challenges in restorations.
• The 90 wt% HEMA/CHXA formulation effectively prevents both bacterial and polymer microleakage by utilizing swelling compensation and sustained antibacterial release.
• These findings suggest a promising new class of antibacterial dental restorative materials with improved clinical performance and longevity.