Evaluation of photosensitizer penetration into sound and decayed dentin: A photoacoustic spectroscopy study

Publication date: March 2018
Source:Photodiagnosis and Photodynamic Therapy, Volume 21
Author(s): Ingrid Gomes Perez Occhi-Alexandre, Mauro Luciano Baesso, Francielle Sato, Lidiane Vizioli de Castro-Hoshino, Pedro Luiz Rosalen, Raquel Sano Suga Terada, Antonio Medina Neto, Mitsue Fujimaki
BackgroundPhotodynamic therapy (PDT) may have topical indications. In those cases it is important for a topical photosensitizer to penetrate into the tissue to which it has been applied. This study aimed to compare the penetration of two different concentrations of erythrosine into intact and in vitro decayed dentin samples.MethodsThis in vitro study evaluated erythrosine (0.3 and 5%) penetration into sound (intact) and decayed dentin. A total of 11 dentin discs were prepared and divided into two equal halves, in order to keep one half sound while the other half was submitted to sterilization and an in vitro demineralization model for 5 days. Before erythrosine application, the organic and inorganic composition of all samples was evaluated by Fourier Transform Raman spectroscopy, and after erythrosine application for 30min, the penetration depth was determined by Photoacoustic spectroscopy technique.ResultsThe results indicated that 0.3% erythrosine showed a higher penetration depth into sound dentin (p=0.002); and 5% erythrosine higher penetration into decayed dentin (p<0.001). However considering clinical parameters, no statistically significant difference was found between any of the conditions tested.ConclusionsErythrosine demonstrated ability to penetrate into dentin, irrespective of sound or decayed condition. Photoacoustic spectroscopy can be considered a method for estimating the penetration into hard tissues, and in conjunction with Raman spectroscopy, these are effective methods for evaluating the spectral response of dentin. Considering that erythrosine is capable of penetrating into decayed dentin, clinical trials are needed to test the effectiveness of this photosensitizer in Photodynamic therapy and Antimicrobial Photodynamic therapy.



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