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Antimicrobial efficacy of methylene blue-functionalized graphene oxide-mediated photodynamic therapy against
Rizwan Jouhar1, Mohamad S Halim2, Sayed A Quadri3
1Ph.D. Scholar, Conservative Dentistry Unit, School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kota Bharu, Kelantan, Malaysia.
Objective:
This study assessed the antimicrobial efficacy of photodynamic therapy (PDT) using functionalized graphene oxide with methylene blue (MB/rGO) to achieve root canal disinfection against Enterococcus faecalis.
Methods:
In this in vitro study, E. faecalis biofilms were developed on 105 single-rooted teeth after decoronation over 21 days. Bacterial viability was assessed with colony forming unit (CFU) analysis. Six experimental groups with equal numbers of samples (n = 15) were treated with 5 % NaOCl (groups 1 and 2), MB-based PDT (groups 3 and 4), or MB/rGO-based PDT (groups 5 and 6). Sonic activation (groups 2, 4, and 6) was performed at 6000 cpm for 2 min, whereas laser activation (groups 3-6) was performed with a 650 nm, 200 mW laser for 2 min. Post-treatment CFU/mL counts and bacterial load decreases were recorded.
Results:
A substantial decrease in bacterial load (p < 0.001) was observed across all experimental groups. The highest decrease (99.99 %) was observed in group 6 (modified PDT with MB/rGO), which also had the lowest CFU (1.21 × 103/mL) and the highest negative culture rate (40 %). Group 4 (modified PDT with MB) showed similar efficacy (99.99 % decrease, 33.33 % negative cultures), whereas NaOCl irrigation (group 1) showed the smallest decrease (99.83 %) and no negative cultures.
Conclusion:
Functionalized MB/rGO with sonic and laser activation achieved the highest bacterial load decrease, and was closely followed by modified PDT with MB. NaOCl irrigation was effective but did not yield negative cultures. Our findings highlight the potential of modified PDT for enhanced root canal cleaning.
Insights
Photodynamic therapy (PDT) using methylene blue with functionalized graphene oxide (MB/rGO) significantly enhanced root canal disinfection against Enterococcus faecalis. This novel approach demonstrated superior antimicrobial efficacy compared to traditional methods.
Area of Science:
- Biomedical Engineering
- Microbiology
- Dental Materials Science
Background:
- Root canal disinfection is crucial for endodontic treatment success.
- Enterococcus faecalis is a persistent pathogen in persistent root canal infections.
- Conventional disinfection methods have limitations in eradicating biofilm.
Purpose of the Study:
- To evaluate the antimicrobial efficacy of photodynamic therapy (PDT) using methylene blue functionalized graphene oxide (MB/rGO).
- To compare the efficacy of MB/rGO-based PDT against Enterococcus faecalis with conventional sodium hypochlorite (NaOCl) irrigation and MB-based PDT.
Main Methods:
- In vitro study using 105 decoronated single-rooted teeth with E. faecalis biofilms.
- Groups treated with NaOCl, MB-based PDT, or MB/rGO-based PDT.
- Sonic and/or laser activation used for PDT groups.
- Bacterial viability assessed via colony forming unit (CFU) analysis.
Main Results:
- All groups showed a significant decrease in bacterial load (p < 0.001).
- MB/rGO-based PDT with sonic and laser activation achieved the highest bacterial reduction (99.99%) and lowest CFU (1.21 × 10^3/mL).
- NaOCl irrigation showed the least efficacy (99.83% reduction) without negative cultures.
Conclusions:
- Functionalized MB/rGO-based PDT offers enhanced root canal disinfection against E. faecalis.
- This modified PDT approach shows significant potential for improving root canal cleaning.
- MB/rGO-PDT presents a promising alternative for endodontic disinfection.
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