(PR79) Photodynamic Therapy with 5-Aminolevulinic Acid and Red LED, in Vitro and in Vivo Studies

Abstract: Photodynamic therapy represented one method of disinfection in endodontics. Enterococcus faecalis was considered a possible cause of failure of endodontic treatment. This study evaluated the in vitro and in vivo effects of the association of a gel containing 5% 5-aminolevulinic acid with a red LED irradiation against E. Faecalis. Test 1: ALAD gel (Aladent, Alphastrumenti, Italy) was added to E. Faecalis broth culture at the final concentration of 50% and 10% v/v, and suspensions were dark incubated at 37°C for 45 min. 10% ALAD were irradiated with 7 and 20min LED device; 50% ALAD irradiated for 7 min. Test 2: E. Faecalis broth culture was incubated for 25 min with ALAD 10%,25%,50%v/v and irradiated for 5min. Exposed and unexposed samples were tested for CFU (cell count) and by LIVE/DEAD (cell viability) analysis. Test 3: in vivo, the samples, taken before the therapy, after application of gel for 45min and after irradiation with red LED, were tested for CFU. ALAD gel, introduced into the canal, was activated by an endodontic tip. 10% ALAD and 45min of incubation promoted a significant reduction of CFUs, but 50% ALAD + LED 7min produced a total inactivation and an evident killing effect on E. faecalis (95% dead cells). The application in vivo of ALAD + LED 7min exerted a significant reduction of cell count. ALAD gel with LED irradiation exerts a potent antibacterial activity against E. Faecalis both in vitro and in vivo. The endodontic fiber can be a valuable aid during endodontic therapy.