Effect of photodynamic antimicrobial chemotherapy on in vitro and in situ biofilms.

The effect of photodynamic antimicrobial chemotherapy (PACT) on oral biofilms was evaluated. Biofilms formed in vitro were treated with sensitizer (S) and/or light (L) in the test (S+L+) and control (S-L-, S+L-, S-L+) groups. Additionally, 21 volunteers wore intraoral devices and the biofilms formed on each side of the device were referred to as S+L+ or S-L- groups. Significant decreases in the viability of in vitro biofilms were observed after PACT. PACT was ineffective in inhibiting multi-species biofilms formed in situ. PACT was effective on in vitro biofilms and was ineffective on in situ biofilms.