Indocyanine Green-Assisted Antibacterial Photodynamic Therapy Notes

Overview of Study

  • Objective: Investigate the use of Indocyanine Green (ICG)-assisted Antibacterial Photodynamic Therapy (aPDT) on dental plaque reduction.

Background

  • Dental Health Statistics: 60-90% of schoolchildren and many adults suffer from dental caries. Severe periodontitis affects 5-15% of populations.

  • Clinical Implications: Poor oral health links to systemic diseases.

Antimicrobial Photodynamic Therapy (aPDT)

  • Mechanism: Combines a light-absorbing photosensitizer (ICG) and light (LED) to generate reactive oxygen species (ROS) that kill bacteria.

    • Effective against bacteria like Streptococcus due to their structural sensitivity to ROS.

  • Advantages: No known resistance formation, effective against biofilms, potential for periodic home use.

Study Design

  • Randomized, split-mouth trial involving 15 healthy adults.

  • Duration: 4-day treatment with daily applications of aPDT.

  • Inclusion criteria: Healthy individuals, aged 18-65, no recent use of antibiotics or antimicrobial mouthwashes.

  • Treatment Application:

    • ICG mixed with water was rinsed in mouth for 60 seconds.

    • LED light (810 nm) applied for 8 minutes per session, targeting a light dose of 100 J/cm².

    • Treatment side randomized by coin flip; other side served as control.

Data Collection

  • Plaque Analysis: Daily imaging of plaque formation on maxillary premolars.

  • Gingival Crevicular Fluid (GCF): Samples collected pre-treatment and daily to measure MMP-8, a marker for gingivitis.

  • Microbiome Analysis: 16S rRNA sequencing to evaluate bacterial composition before and after treatment.

Results

  • Plaque Area: Significantly lower plaque formation on aPDT-treated premolars (35.1%) compared to controls (42.5%).

  • MMP-8 Levels:

    • Reduced MMP-8 concentrations in GCF at treated sites suggest less inflammation and a trend towards lower overall MMP-8 in the aPDT-treated group.

  • Microbiome Changes: A reduction in pathogenic bacteria, such as Streptococcus and Acinetobacteria, accompanied by an increase in beneficial genera, including Neisseria and Haemophilus.

Discussion

  • Efficacy: ICG-aPDT effectively reduced dental plaque and altered the bacterial profile towards a healthier ecosystem.

  • Adherence of ICG: The photosensitizer selectively adhered to dental plaque, enhancing the efficacy of light application.

  • Comparison with Other Treatments: A clear advantage over traditional mouthwashes concerning resistance formation and side effects.

Conclusion

  • ICG-aPDT is promising as a preventive and therapeutic strategy for maintaining oral hygiene.

Future Directions

  • Explore the use of LED-based photodynamic therapy for home use to enhance access while minimizing side effects.ibility