Light activated antimicrobial agents can inactivate oral malodour causing bacteria.

Area of Science:

• Oral microbiology
• Photochemistry
• Antimicrobial therapy

Background:

• Oral malodour affects many, causing significant distress.
• Oral bacteria on the tongue produce volatile sulfur compounds, leading to bad breath.
• Current treatments like mouthwashes are often ineffective at reducing tongue bacteria.

Purpose of the Study:

• To investigate the efficacy of light-activated antimicrobial agents (LAAAs) against oral malodour-causing bacteria.
• To determine if specific oral bacteria are susceptible to photodynamic inactivation.

Main Methods:

• Tested five key oral malodour-causing bacterial species.
• Utilized methylene blue as a photosensitizer.
• Exposed bacteria to 665 nm laser light at a specific fluence (14.53 J cm⁻²).

Main Results:

• Significant bacterial reduction (4.5-5 log₁₀) observed for four species (P. gingivalis, P. intermedia, P. anaerobius, S. moorei) with 20 µM methylene blue and laser light.
• Fusobacterium nucleatum viability dropped below detection limits.
• Methylene blue and 665 nm laser light demonstrated potent antimicrobial activity.

Conclusions:

• Methylene blue combined with 665 nm laser light effectively kills major bacteria responsible for oral malodour.
• Photodynamic therapy presents a viable and effective treatment strategy for oral malodour.
• This approach shows potential as an alternative to conventional chemical treatments.