One of the main causes of composite restoration failure is the formation of bacterial biofilms on their surfaces, which can trigger secondary caries and restoration degradation. To reduce this risk, the development of restorative materials with antibacterial properties or resistance to biofilm adhesion has become an active area of research.
A study conducted by FKG UGM student Daffa Ananda, under the supervision of drg. Heribertus Dedy Kusuma Y., M.Biotech., Ph.D. and drg. Aryan Morita, M.Sc., Ph.D., entitled “Perbandingan Densitas Biofilm pada Permukaan Resin Komposit Nanofil dan Mikrofil Menggunakan Metode Dinamis dan Statis”, examined how different composite types influence biofilm density on their surfaces—an important consideration in designing antibacterial restorative materials.
Summary of the UGM Study
- The study used microfill and nanofill composite resin samples in cylindrical form (5 mm diameter, 2 mm thickness), divided into static and dynamic culture groups (using a microfluidic chamber).
- The biofilm consisted of a co-infection culture of Streptococcus mutans and Candida albicans. After 18 hours of incubation, crystal violet staining was performed, and biofilm optical density was measured using a microplate reader at a wavelength of 450 nm.
- Results: No significant difference was found between microfill and nanofill composites in biofilm density under either static or dynamic culture conditions (p > 0.05).
These findings indicate that despite differences in filler particle size and surface properties, both composite types exhibited similar levels of biofilm formation under the study conditions.
Biofilm Challenges and the Need for Antibacterial Materials
Why Is Biofilm a Threat?
- Bacteria such as S. mutans can form extracellular polymeric substance (EPS) matrices that adhere to restorative surfaces, protecting bacteria and producing acids that damage tooth structures.
- Restorative surfaces with micro-roughness or surface retention facilitate bacterial colonization.
- Residual monomers in composite resins (e.g., TEGDMA) may stimulate bacterial activity or polymer degradation, leading to the release of toxic compounds.
Antibacterial Material Strategies
Approaches to designing restorative materials with antibacterial effects include:
- Incorporation of Antibacterial Agents
- Controlled release of metal ions (e.g., silver, copper, zinc).
- Antibacterial molecules such as quaternary ammonium compounds (QAC), chlorhexidine, or antimicrobial nanoparticles.
- Ion-Releasing / Bioactive Materials
- Restorative materials that release ions (e.g., fluoride, calcium, phosphate) to create environments less favorable for bacteria.
- Bioactive composites that support both remineralization and antibacterial activity.
- Anti-Adhesion / Biofilm-Resistant Surfaces
- Hydrophobic or super-hydrophilic surfaces that inhibit bacterial adhesion.
- Surface topography modification (nano-texturing) to reduce microscopic colonization niches.
- Dual Therapy Systems
- Combination of mechanical approaches (surface finishing and polishing), minimal microgap restoration design, and antibacterial restorative materials.
Limitations and Clinical Considerations
The UGM study demonstrates that differences in filler size alone are insufficient to guarantee antibacterial effects. Other factors—including surface roughness after aging, finishing and polishing, pH cycling, and long-term stability of antibacterial agents—must be considered. Uncontrolled release of antimicrobial agents may pose toxicity risks or compromise the mechanical properties of restorations.
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Antibacterial restorative materials represent an important direction in reducing restoration failure due to secondary caries. The UGM study on biofilm density highlights that composite type alone (microfill vs. nanofill) does not necessarily determine bacterial adhesion. These findings underscore the need for additional antibacterial properties, such as antimicrobial ion release, anti-adhesive surfaces, or combined strategies.
References
DAFFA ANANDA, drg. Heribertus Dedy Kusuma Y., M.Biotech., Ph.D., drg. Aryan Morita, M.Sc., Ph.D., Perbandingan Densitas Biofilm pada Permukaan Resin Komposit Nanofil dan Mikrofil Menggunakan Metode Dinamis (Microfluidic Chamber) dan Metode Statis, https://etd.repository.ugm.ac.id/home/detail_pencarian_downloadfiles/1170572
Author: Rizky B. Hendrawan | Photo: Freepik
