title: Antimicrobial photodynamic therapy as a strategy to arrest enamel demineralization: a short-term study on incipient caries in a rat model.
abstract: In this study we developed a rat model of incipient caries to investigate the short-term effects of antimicrobial photodynamic therapy (aPDT) on oral microbiota regulation and demineralization arrestment. Twenty-nine male rats were submitted to caries induction. Early carious lesion was confirmed by optical coherence tomography (OCT) 5 days after experiment beginning in five animals. The remaining animals (n = 24) were randomly divided into two groups: control (n = 12), animals were untreated; and aPDT (n = 12), animals were treated with 100 μM of methylene blue for 5 min and irradiated by a light emitting diode at λ = 645 ± 30 nm, fluence rate of 480 mW cm(-2) and exposure time of 3 min. Bacterial burden was evaluated before, immediately after, 3, 7 and 10 days following treatment, and total number of microaerophilic bacteria was counted. OCT was also used to quantify teeth demineralization. A significant bacterial decrease of about 1.6 log was observed immediately after aPDT. Besides, bacterial load in aPDT group remained lower than control until 10 days post-treatment (P < 0.05) and variation of optical attenuation coefficient before and after aPDT was 15%, corroborating to caries arrestment. Put together, these findings suggest that aPDT was competent to reduce cariogenic bacteria and to avoid further mineral loss.
authors.affiliation: Centro de Lasers e Aplicações-Instituto de Pesquisas Energéticas e Nucleares IPEN-CNEN/SP, São Paulo, SP, Brasil.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Baptista
authors.forename: Ilka T
authors.initials: IT
authors.lastname: Kato
authors.forename: Renato A
authors.initials: RA
authors.lastname: Prates
authors.forename: Luis C
authors.initials: LC
authors.lastname: Suzuki
authors.forename: Marcus P
authors.initials: MP
authors.lastname: Raele
authors.forename: Anderson Z
authors.initials: AZ
authors.lastname: Freitas
authors.forename: Martha S
authors.initials: MS
authors.lastname: Ribeiro
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003731:Dental Caries / Q000517:prevention & control*; D003743:Dental Enamel; D008297:Male; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D041623:Tomography, Optical Coherence; D017001:Tooth Demineralization / Q000517:prevention & control*
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents