title: Photodynamic inactivation of a multispecies biofilm using Photodithazine(®) and LED light after one and three successive applications.
abstract: In this investigation, the effectiveness of successive applications of antimicrobial photodynamic inactivation (API) mediated by Photodithazine(®) (PDZ) and LED light was evaluated against a multispecies biofilm formed by Candida albicans, Candida glabrata, and Streptococcus mutans on denture base acrylic resin. Standard cell suspensions (bacteria and yeast) were inoculated on acrylic resin samples, and the biofilm was grown for 48 h (37 °C/75 rpm). API was performed by the administration of PDZ (175 and 200 mg/L) and exposure to 37.5 J/cm(2) of LED light (660 nm). Additional samples were treated with PDZ or LED light only. Untreated control samples were not submitted to light or PDZ. The conditions described were applied once or in three consecutive applications for all groups. Cell viability was determined by colony counts (CFU/mL), metabolic activity, total biomass, and confocal laser scanning microscopy (CLSM). Data were analyzed by a nonparametric two-way ANOVA and Tukey tests (α = 0.05). The results obtained demonstrated a significant effect (p < 0.05) of number of applications and treatment groups for CFU/mL, and S. mutans showed the highest susceptibility to API. The metabolic activity of the multispecies biofilm was significantly reduced (p < 0.05) after API for both numbers of applications, which were also significantly different (p < 0.05) between them. The total biomass of the biofilm was significantly different (p < 0.05) only between groups submitted to one and three API applications. CLSM showed a visual increase of dead cells after API. API-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. Three consecutive applications of API were more effective for reducing the cell viability and the total biomass of multispecies biofilm.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP, Univ Estadual Paulista, Rua Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. criscquishida@gmail.com.
authors.forename: Cristiane Campos Costa
authors.initials: CC
authors.lastname: Quishida
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP, Univ Estadual Paulista, Rua Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. ewertonmima@foar.unesp.br.
authors.forename: Ewerton Garcia de Oliveira
authors.initials: EG
authors.lastname: Mima
authors.affiliation: Department of Social Dentistry, Araraquara Dental School, UNESP - Univ Estadual Paulista, Rua Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. lidovigo@foar.unesp.br.
authors.forename: Lívia Nordi
authors.initials: LN
authors.lastname: Dovigo
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP, Univ Estadual Paulista, Rua Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. janainahj@foar.unesp.br.
authors.forename: Janaina Habib
authors.initials: JH
authors.lastname: Jorge
authors.affiliation: Physics Institute of São Carlos, USP, University of São Paulo, Av. Trabalhador São-Carlense, 400, CEP: 13566-590, São Carlos, SP, Brazil. vander@ifsc.usp.br.
authors.forename: Vanderlei Salvador
authors.initials: VS
authors.lastname: Bagnato
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP, Univ Estadual Paulista, Rua Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. pavarina@foar.unesp.br.
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
mesh_terms: D000180:Acrylic Resins; D000890:Anti-Infective Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000528:radiation effects*; D002176:Candida albicans / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D041221:Candida glabrata / Q000187:drug effects / Q000528:radiation effects; D003819:Denture Bases / Q000382:microbiology; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008027:Light; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects*; D018613:Microscopy, Confocal; D013295:Streptococcus mutans / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects
chemical_list: D000180:Acrylic Resins; D000890:Anti-Infective Agents; C047635:N-methylglucosamine; D005944:Glucosamine
keywords: Acrylic resin; Biofilm; Candida albicans; Candida glabrata; Photodynamic therapy; Streptococcus mutans