Antibacterial resin-based composite containing chlorhexidine for dental applications

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Dental composites are susceptible to bacterial colonization and biofilm formation, leading to secondary caries.
• Incorporating antibacterial agents into composite materials is a promising strategy to enhance their clinical performance and longevity.
• Montmorillonite (MMT) clay can be loaded with antimicrobial agents like chlorhexidine (CHX) for controlled release applications.

Purpose of the Study:

• To develop and characterize a novel composite material incorporating MMT loaded with CHX.
• To evaluate the antibacterial activity, drug release kinetics, and effect on biofilm formation of the developed composite.
• To assess the impact of MMT/CHX on the physical and mechanical properties of the BisGMA/TEGDMA composite matrix.

Main Methods:

• Six experimental composites were fabricated using a BisGMA/TEGDMA matrix with varying concentrations (2.5%, 5%, 10%) of MMT loaded with CHX.
• Degree of conversion (FTIR), flexural properties (three-point bending), antibacterial activity (inhibition halo), biofilm formation (colonized culture media), and CHX release (UV spectroscopy) were evaluated.
• Statistical analysis included Kruskal-Wallis, Mann-Whitney, and two-way ANOVA with Tukey's post-hoc test.

Main Results:

• Composites exhibited degrees of conversion (71-74%), elastic modulus (5.7-8.1 GPa), and flexural strength (61.4-74.7 MPa) with no significant differences among groups.
• All MMT/CHX concentrations demonstrated antibacterial activity against Staphylococcus aureus, Streptococcus mutans, and Porphyromonas gingivalis, except for 2.5% against P. gingivalis.
• Reduced biofilm formation was observed, particularly with 10% MMT/CHX, and sustained CHX release occurred over 28 days.

Conclusions:

• The developed MMT/CHX composites effectively release CHX, exhibit antibacterial properties, and reduce biofilm formation.
• The incorporation of MMT/CHX did not negatively impact the degree of conversion or mechanical properties of the composite.
• These findings suggest the potential of MMT/CHX composites as an advanced dental restorative material with enhanced antimicrobial efficacy.