Evaluation of Photodynamic Therapy Using a Diode Laser 635 nm as an Adjunct to Conventional Chemo-Mechanical Endodontic Procedures against Enterococcus faecalis Biofilm: Ex-Vivo Study

Abstract

The study aimed to evaluate the antimicrobial effect of photodynamic therapy (PDT) with the use of Toluidine Blue (TB) on extracted teeth infected with biofilms of Enterococcus faecalis. Fifty-four extracted teeth with single-roots and single canals were mechanically shaped, autoclaved, and contaminated with E. faecalis. They were randomly divided into six groups: two groups were negative and positive control groups, two groups were subjected to mechanical instrumentation and PDT with different pre-irradiation times and irradiation times, and two groups were subjected to chemo-mechanical endodontic treatment and PDT with different pre-irradiation times and irradiation times. In PDT groups, after the application of TB, the canals were irradiated with a diode laser of wavelength 635 nm, with a fiber diameter of 200 μm and 100 mW of power in continuous mode. The bacterial load was evaluated using a BioTimer Assay protocol. The greatest reduction of bacterial load was observed in groups of combined PDT with chemo-mechanical treatment. The reductions of bacterial load in groups of combined PDT with chemo-mechanical treatment, and in the positive control group, were significant (p < 0.01) when compared to that of the negative control group. Photodynamic therapy as an adjunctive modality may improve the disinfection capacity of conventional endodontic treatment against E. faecalis.

Evaluation of pH and Optical Properties of Dual Rinse HEDP Irrigating Solution

“…However, lasers operating in the VL range have been used in endodontics, such as KTP lasers emitting at 532 nm that have been studied for sterilizing root canals [60,61] and He-Ne lasers at 633 nm that were used for Laser Doppler Flowmetry [62]. Another promising aspect of laser-aided endodontics is photodynamic therapy that involves the use of a photosensitive dye (photosensitizer) and a low-intensity laser light to achieve antibacterial and tissue disinfection effects within the root canal system [63,64]. Photosensitizers aid the rise in the absorption coefficient of water in root canals, making lasers effective in the VL region [63].…”

“…Photosensitizers aid the rise in the absorption coefficient of water in root canals, making lasers effective in the VL region [63]. Diode lasers operating at 635 nm have shown promising efficiency in photodynamic endodontic therapy, where the photosensitizer has been combined with conventional chemo-mechanical debridement [64].…”

Antimicrobial photodynamic therapy for the treatment of oral infections: A systematic review

“…reported that TB when paired with a 635 nm diode laser enhanced the disinfection of E. faecalis in conventional endodontic surgery. 109 Another research by Sarda et al. focused on the effectiveness of various germicidal methods, including the use of diode lasers, MB-mediated aPDT and the chemical agent (sodium hypochlorite), as well as combinations of these methods.…”

Analysis of the Effectiveness of Using a Laser Photodynamic System for the Treatment of Chronic Apical Periodontitis. Clinical Cases Series

“…Using HELBO Blue Photosensitizer, which diffuses into biofilms, the walls of bacterial cells are stained with light-sensitive molecules. [27][28][29] Next, the molecules are activated using laser light with a wavelength of 670-690 nm and an energy density of 75 mW/cm 2 . 24 The absorption of light quanta by photosensitase molecules in the presence of oxygen leads to a photochemical reaction, as a result of which molecular triplet oxygen is converted into singlet oxygen, which destroys microorganisms in the biofilm.…”