title: Biofilm formation in Haas palatal expanders with and without use of an antimicrobial agent: an in situ study.
abstract: Orthodontic appliances causes specific alterations in oral environment, including reduction of pH, increase of dental biofilm and elevation of salivary microbial levels, causing an increased risk for dental caries. This study evaluated, using microbial culture and scanning electron microscopy (SEM), the in situ contamination by mutans streptococci (MS) of different surfaces of Haas palatal expanders with and without use of chlorhexidine gluconate mouthrinses (CHX). Thirty-four patients were randomly assigned to two groups (n = 17/group), using placebo (Group I) and 0.12% CHX (Group II-Periogard®) mouthrinses twice a week. After 4 months, appliances were submitted to microbiological processing and after fragments were analyzed by SEM. Mann-Whitney U test (α = 5%) was used to assess differences between groups on the appliances' different surfaces and to compare the contamination on the free and nonfree surfaces of these components. There was no difference (p = 0.999) between groups regarding the number of MS colonies/biofilms on the nonfree surfaces, which showed intense contamination. However, free surfaces of Group II presented less contamination (p < 0.001) than those of Group I in all appliances' components. Results of the microbial culture were confirmed by SEM. Use of 0.12% CHX was effective in reducing the formation of MS colonies/biofilms on free surfaces of Haas expanders, in situ.
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Cristhiane Ristum
authors.initials: CR
authors.lastname: Bagatin
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Marcela Cristina Damião
authors.initials: MCD
authors.lastname: Andrucioli
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: José Tarcísio Lima
authors.initials: JTL
authors.lastname: Ferreira
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Mírian Aiko Nakane
authors.initials: MAN
authors.lastname: Matsumoto
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Raquel Assed Bezerra
authors.initials: RAB
authors.lastname: da Silva
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Lea Assed Bezerra
authors.initials: LAB
authors.lastname: da Silva
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Fábio Lourenço
authors.initials: FL
authors.lastname: Romano
authors.affiliation: Department of Pediatric Clinic School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Nelson-Filho
mesh_terms: D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002648:Child; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000382:microbiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D009067:Mouthwashes / Q000494:pharmacology*; D000077744:Orthodontic Appliances, Fixed / Q000382:microbiology*; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D000891:Anti-Infective Agents, Local; D009067:Mouthwashes; C010882:chlorhexidine gluconate; D002710:Chlorhexidine
keywords: biofilms; chlorhexidine, Streptococcus mutans; orthodontic appliances