In Vitro effect of low-level laser therapy on typical oral microbial biofilms

• Published in: Brazilian dental journal Vol. 22; no. 6; p. 502
• Main Authors: Basso, Fernanda G, Oliveira, Camila F, Fontana, Amanda, Kurachi, Cristina, Bagnato, Vanderlei S, Spolidório, Denise M P, Hebling, Josimeri, de Souza Costa, Carlos A
• Format: Journal Article
• Language: English
• Published: Brazil 2011
• Subjects: Bacteriological Techniques; Biofilms - growth & development; Biofilms - radiation effects; Candida albicans - growth & development; Candida albicans - radiation effects; Candida albicans - ultrastructure; Coloring Agents; Dose-Response Relationship, Radiation; Humans; Hyphae - radiation effects; Lasers, Semiconductor; Low-Level Light Therapy - instrumentation; Materials Testing; Microbial Interactions - radiation effects; Microbial Viability - radiation effects; Microscopy, Electron, Scanning; Mouth - microbiology; Mycology - methods; Radiation Dosage; Streptococcus mutans - growth & development; Streptococcus mutans - radiation effects; Streptococcus mutans - ultrastructure; Succinate Dehydrogenase - analysis; Temperature; Tetrazolium Salts; Thiazoles; Time Factors
• ISSN: 1806-4760

The aim of this study was to evaluate the effect of specific parameters of low-level laser therapy (LLLT) on biofilms formed by Streptococcus mutans, Candida albicans or an association of both species. Single and dual-species biofilms--SSB and DSB--were exposed to laser doses of 5, 10 or 20 J/cm(2) from a near infrared InGaAsP diode laser prototype (LASERTable; 780 ± 3 nm, 0.04 W). After irradiation, the analysis of biobilm viability (MTT assay), biofilm growth (cfu/mL) and cell morphology (SEM) showed that LLLT reduced cell viability as well as the growth of biofilms. The response of S. mutans (SSB) to irradiation was similar for all laser doses and the biofilm growth was dose dependent. However, when associated with C. albicans (DSB), S. mutans was resistant to LLLT. For C. albicans, the association with S. mutans (DSB) caused a significant decrease in biofilm growth in a dose-dependent fashion. The morphology of the microorganisms in the SSB was not altered by LLLT, while the association of microbial species (DSB) promoted a reduction in the formation of C. albicans hyphae. LLLT had an inhibitory effect on the microorganisms, and this capacity can be altered according to the interactions between different microbial species.