Comparison between Single and Multi-LED Emitters for Photodynamic Therapy: An In Vitro Study on Enterococcus faecalis and Human Gingival Fibroblasts

Abstract

Aim of the study: The aim was to evaluate the effects of two LED devices, TL-01 and TL-03 in photodynamic therapy (PDT), on Enterococcus faecalis and on human gingival fibroblasts (HGFs). TL-01, characterized by a single emitter, irradiates one periodontal site at a time, whereas the multi-led device (TL-03) irradiates all vestibular sites of a single arch at a time. Methods: E. faecalis bacterial suspensions and HGFs were incubated for 45 min with Aladent gel (ALAD) containing 5-aminolevulinic acid and then exposed to LED devices (ALAD-PDT), having different distance and timing of irradiation (TL-01 N (0.5 mm, for 7 min), TL-03 N (0.5 mm, 15 min) and TL-03 F (30.0 mm, 15 min)). For bacterial suspension, the colony forming units and the live/dead staining were evaluated after 24 h, while the protoporphyrin IX (PpIX) content was monitored in all phases of the experimentation. For HGFs, the cell viability, proliferation, cell morphology, and adhesion were evaluated at 24 h. Results: Both TL-01 and TL-03 showed a significant reduction of bacterial load. The photoinactivation was inversely proportional to the PpIX accumulation. TL-01 and TL-03 promoted proliferation and adhesion of HGFs. Conclusions: Both tested devices for ALAD-PDT were equally effective in significantly reducing Enterococcus faecalis growth and in promoting HGFs proliferation and adhesion, in vitro.

Antimicrobial Combined Action of Graphene Oxide and Light Emitting Diodes for Chronic Wound Management

“…The microbial population decreased, indicating a growth inhibition effect versus the control, without a killing action. Instead, remarkable cell death was detected in presence of ala. As demonstrated by Petrini et al [28], the gel could englobe and suffocate the cells most susceptible to the treatment.…”

“…Finally, PpIX, under irradiation, serves as an in situ photosensitizer, leading to bacterial inactivation [27]. In an in vitro study, Petrini et al [28] demonstrated the increase in fluorescence of PpIX after the addition of ALAD gel to E. faecalis solution and after the LED irradiation, the endogenous PpIX produced remarkable cell death.…”

“…During the experiments, the LED handpiece was mounted perpendicularly to the LCWB sample at a 0.5-mm distance. Irradiation was performed under a laminar flow hood in the dark, under aseptic conditions [20,28,42]. For the tests, 630 nm LED alone and plus ALAD (ALAD-PDT) were used.…”

The Effects of 5% 5-Aminolevulinic Acid Gel and Red Light (ALAD-PDT) on Human Fibroblasts and Osteoblasts

“…Previous results of in vitro and in vivo studies concerning the ALAD-PDT protocol applied to treat oral infections by killing microbes [ 10 , 11 , 12 , 15 ] drove us to test the same protocol to investigate whether ALAD-PDT may have some effects on cell populations of the oral cavity such as gingival fibroblasts and oral osteoblasts derived from human biopsies.…”

“…Consequently, the 630 nm light irradiation of cells with an increased accumulation of PpIX promotes a highly selective production of ROS, and decreased levels of mitochondrial membrane potential, which induces cell death by both apoptosis and necrosis without damaging the surrounding healthy cells [ 9 ]. The ability of ALAD-PDT to inactivate both Gram-positive and -negative bacteria has been shown in different in vitro studies [ 10 , 11 , 12 ]. ALAD-PDT is effective for biofilm removal from different titanium surfaces, showing encouraging results against peri-implantitis and chronic wounds [ 11 , 13 ].…”