Effect of methylene blue-mediated antimicrobial photodynamic therapy on dentin caries microcosms

• Published in: Lasers in medical science 2018-04, Vol.33 (3), p.479-487
• Main Authors: Méndez, Daniela Alejandra Cusicanqui, Gutierrez, Eliezer, Dionísio, Evandro José, Oliveira, Thaís Marchini, Buzalaf, Marília Afonso Rabelo, Rios, Daniela, Machado, Maria Aparecida Andrade Moreira, Cruvinel, Thiago
• Format: Article
• Language: English
• Subjects: Acid production; Anaerobic conditions; Animals; Anti-Infective Agents - pharmacology; Anti-Infective Agents - therapeutic use; Antiinfectives and antibacterials; Antimicrobial agents; Bacteria - drug effects; Biofilms; Biofilms - drug effects; Cattle; Child; Colony Count, Microbial; Deionization; Dental caries; Dental Caries - drug therapy; Dental Caries - microbiology; Dental materials; Dentin; Dentin - drug effects; Dentistry; Humans; Lactic acid; Lactobacilli; Lasers; Medicine; Medicine & Public Health; Methylene blue; Methylene Blue - pharmacology; Methylene Blue - therapeutic use; Microbial Viability - drug effects; Microcosms; Microorganisms; Optical Devices; Optics; Original Article; Photochemotherapy; Photodynamic therapy; Photonics; Photosensitizing Agents - pharmacology; Photosensitizing Agents - therapeutic use; Quantum Optics; Spectrophotometry; Statistical analysis; Sucrose; Sugar; Viability
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-017-2379-3

Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjuvant treatment of dental caries, although there are no well-defined protocols to its clinical application. This study aimed to evaluate the influence of aPDT on the viability of microorganisms, vitality of biofilms, and lactic acid production of dentin caries microcosms. Biofilms were grown on bovine dentin discs in anaerobic conditions at 37 °C for 5 days, inoculating infected carious dentin in modified McBain medium plus 1% sucrose. The biofilms were treated by the combination of deionized water or 100 mg L −1 methylene blue (MB) with 0, 37.5, or 75 J cm −2 LED at 630 nm. The counts of total microorganisms, total streptococci, mutans streptococci, and total lactobacilli were determined by colony-forming units (CFU). The vitality of microbial cells in intact biofilms was measured by confocal laser scanning microscope (CLSM). The lactic acid production was analyzed by enzymatic spectrophotometry at 340 nm. Statistical analysis was conducted by Kruskal-Wallis and post hoc Dunn’s tests ( P