Melanin pigmented gingival tissue impairs red-light lateral scattering for antimicrobial photodynamic therapy.

Autor: Fruet-Arruda RT; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil., Anselmo GG; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil., Tortamano ACAC; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil., Rossi AL; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil., Biffi MB; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil., Marco RL; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil., da Silva DFT; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil., Kato IT; Department of Biomedical Engineering, ABC Federal University (UFABC), São Bernardo do Campo, SP, Brazil., Nuñez SC; Department of Bioengineering, Universidade Brasil, São Paulo, Brazil., Prates RA; Biophotonics Applied to Health Science Post Graduate Program, Nove de Julho University - UNINOVE, São Paulo, Brazil; School of Dentistry, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil. Electronic address: pratesra@uni9.pro.br.
Jazyk: angličtina
Zdroj: Photodiagnosis and photodynamic therapy [Photodiagnosis Photodyn Ther] 2021 Mar; Vol. 33, pp. 102135. Date of Electronic Publication: 2021 Jan 20.
DOI: 10.1016/j.pdpdt.2020.102135
Abstrakt: Gingival melanin pigmentation is present in many African and Oriental descendant people and its occurrence in patients may interfere with the absorption and scattering of therapeutic doses of light. Antimicrobial photodynamic therapy (aPDT) is used as an adjunctive treatment for periodontitis and light irradiation may be impaired by tissue size and its melanin content. The aim of this clinical study was to measure the red-light attenuation in gingival tissue naturally pigmented with melanin. Ten patients with melanized gingival tissue were selected and irradiated by 100 mW red laser. The patients were photographed in frontal and incisal regions with a T2i camera (Canon, Japan) with 100 mm macro lens, 35 mm focal length, aperture f22, 1/100 shutter speed and ISO 200. Three randomly selected sites of each patient were used for evaluations and the irradiation values were assessed in the IMAGEJ software (NIH, Wayne Rasband, USA). Intensity in pixels was quantified in relation to the distance from the light incident point. Data were normalized and the results were presented as relative light intensity as a function of distance. The results demonstrated that red laser light is exponentially attenuated as a function of lateral distance and loses approximately 50 % of its intensity by 2.23 mm. On the other hand, the light travels 3 mm in depth to decay 50 %. In conclusion, our data suggest that melanin presence decreases optical pathway and irradiation protocols for antimicrobial photodynamic therapy in gingival tissue should consider light attenuation and depth of periodontal pockets so that efficient illumination of the target tissue occurs. Periodontal pockets bigger than 6 mm should be irradiated with more than one point.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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