14 June 2021

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5-aminolevulinic acid and led against peri-implant disease

Authors: Morena Petrini, Matteo Mancini, Giovanna Iezzi, Adriano Piattelli, Emanuela Di Campli, Simonetta D’Ercole

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Peri-implant disease includes both a reversible inflammatory process, called peri-mucositis and peri-implantitis, in which progressive reabsorption of the supporting bone causes irreversible effects.

The etiological factors of peri-implant disease follow, in part, those of periodontal pathology. The high presence of biofilm around the implants turns out to be the predisposing factor, but from a microbiological point of view, it is a more heterogeneous and complex infection, consisting mainly of gram-negative bacteria, compared to periodontitis.

Currently, the decontamination and disinfection of the implant surface represent the first treatment step, however, this process is made very difficult, both for the difficulty of accessing the operating field, and for the surface roughness of the implants, and for the resistance by the bacterial biofilm upon penetration by antibiotics.

Due to these factors, the treatment of peri-implant disease still represents a great challenge for the dentist and the study of new technologies is still ongoing in order to find increasingly effective tools.

Among these, the use of light-based devices, such as LEDs or lasers, with or without the additional use of photosensitizers, has shown results that are still controversial, but albeit encouraging.

In particular, previous literature shows us how the association between 5-aminolevulinic acid and red LED light has a high antibacterial effect against gram-positive bacteria. However, the efficacy against gram-negative bacteria, the main actors in the etiology of peri-implant disease, is controversial.

The aim of this study is to evaluate the effect of a new gel containing 5-aminolevulinic acid, ALAD, tested at different concentrations and exposed to different irradiation times of red LED, on Pseudomonas aeruginosa.

P. aeruginosa is a gram-negative bacterium, particularly important for its resistance to antibiotics and, in dentistry, for its frequent association with peri-implantitis.

Pseudomonas aeruginosa was cultivated, in vitro and subjected to different protocols which included: incubation with Aladent gel, ALAD (Aladent, Alphastrumenti, Melzo (MI), Italy) at different concentrations and/or irradiation with red LED light (630 nm). The count of colony-forming bacterial units (CFU / mL) was measured and comparisons were made between the different groups.

1 hour of incubation with ALAD followed by 7 minutes of irradiation with red LED light allowed the total elimination of bacteria. The red LED light irradiation, without adding gel, significantly reduced the bacterial count, compared to the controls.

Even the use of ALAD alone, without irradiation, was able to promote a significant reduction in the bacterial count, proportional to the gel concentration.

In conclusion, we can deduce that the new gel is effective in significantly reducing in vitro gram-negative bacteria such as Pseudomonas aeruginosa. The association of 7 minutes of irradiation with red LED light with the gel allows for the total inactivation of the bacteria.

The combination of ALAD gel and irradiation with red LED light is an additional tool for bacterial inactivation in the treatment of dental implants contaminated and/or affected by mucositis and peri-implantitis.