title: Comparative analyses of ion release, pH and multispecies biofilm formation between conventional and bioactive gutta-percha.
abstract: OBJECTIVE
  To analyse the effect of commercial and experimental gutta-percha with the addition of niobium phosphate glass on biofilm formation by oral bacteria from human dental plaque. Additional pH and elemental release of the materials were analysed.
  
  
  METHODS
  The multispecies biofilm was grown anaerobically from plaque bacteria on standardized discs of each material: hydroxyapatite (HA), gutta-percha pellets (OBT) (Obtura pellets, Shoreline, CT, USA), ProTaper gutta-percha (PTP) (ProTaper Universal Gutta-Percha Points, Dentsply Maillefer, Ballaigues, Switzerland), EndoSequence BC gutta-percha (GBC) (Brasseler USA, Savannah, GA, USA), experimental gutta-percha associated with niobium phosphate glass (GNB) and niobium phosphate glass (NPG). Specimens (n = 5 per group and per incubation period) were incubated in brain-heart infusion broth for 3, 14 and 30 days, at 37 °C, and stained using live/dead viability assay. Images were analysed by confocal laser scanning microscopy (CLSM) and the total biovolume (mm3), viable bacteria biovolume (mm3), and live percentage (%) were quantified. For pH measurement, specimens of each material (n = 3) were immersed in phosphate-buffered saline at 37 °C, and pH was monitored in multiple intervals, up to 30 days. For elemental analysis, additional specimens (n = 3) were immersed in deionized water and elemental release was analysed by ICP-OES (inductively coupled plasma - optical emission spectrometry) at time intervals of 3, 14 and 30 days. Differences between groups were evaluated by the two-way analysis of variation (anova) with Tukey's post hoc test (P < 0.05).
  
  
  RESULTS
  The lowest total biovolume at 30 days was found in GNB, GBC and NPG. GNB had the lowest viable bacteria biovolume (mean value) at 30 days (P < 0.05), and the lowest live percentage of bacteria at 3 and 30 days (P < 0.05), whilst NPG had the lowest live percentage at 14 days (P < 0.05). GNB had the highest pH (8.45) after 30 days (P < 0.05), and the greatest Zn and Na release at all time intervals (P < 0.05). Both GBC and GNB had significantly higher Ca release at 14 and 30 days.
  
  
  CONCLUSIONS
  GNB and GBC reduced biofilm formation, GNB had the lowest amount of viable bacteria in biofilms with the highest pH, and high Zn and Na release values after 30 days.
authors.affiliation: School of Dentistry, University Center of Maranhão-UniCeuma, São Luís, Brazil.|Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil.
authors.forename: C N
authors.initials: CN
authors.lastname: Carvalho
authors.affiliation: Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada.
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Gavini
authors.affiliation: Center of Materials Science and Technology, Energy and Nuclear Research Institute, São Paulo, Brazil.
authors.forename: J R
authors.initials: JR
authors.lastname: Martinelli
authors.affiliation: Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Manso
authors.affiliation: Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada. markush@dentistry.ubc.ca.
authors.forename: M
authors.initials: M
authors.lastname: Haapasalo
mesh_terms: D018441:Biofilms; D017886:Durapatite; D005898:Glass; D006171:Gutta-Percha / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D009556:Niobium; D012387:Root Canal Filling Materials / Q000737:chemistry
chemical_list: D012387:Root Canal Filling Materials; D009556:Niobium; D006171:Gutta-Percha; D017886:Durapatite
keywords: antibiofilm; bioactive glass; confocal laser scanning microscopy; gutta-percha; niobium