title: Analysis of the properties of dental cements after exposure to incubation media containing Streptococcus mutans.
abstract: OBJECTIVE
  Indirect restorations are increasingly used in dentistry, and the cementation interface is possibly the most critical region of the work. The objective of the present work was to evaluate the influence of exposure to a culture medium containing S. mutans on the hardness and solubility of four different cementing agents (zinc phosphate, glass ionomer, glass ionomer modified with resin and resin cement).
  
  
  METHODS
  Test specimens composed of these cements were exposed for 30 days in a culture medium containing S. mutans. After leaching, the test materials were assessed in terms of their solubility (loss of mass) and Knoop (KHN) microhardness. Changes in surface morphology were identified using scanning electron microscopy (SEM).
  
  
  RESULTS
  The resin cement showed no significant solubility and its hardness increased following exposure and leaching, while the zinc phosphate cement was the most soluble and its hardness decreased after exposure to the culture medium. SEM analyses identified morphological alterations on the surfaces of the test materials that were compatible with the solubility results.
  
  
  CONCLUSIONS
  It is concluded that resinous cements perform better than water-based cements when exposed to acidic conditions.
  
  
  CONCLUSIONS
  The effects of acids from Streptococcus mutans can interfere with the efficiency and properties of some cements used for fixation of indirect restorations, exposed to the buccal environment.
authors.affiliation: Department of Dental Materials, University of Uberaba Minas Gerais, Brazil. fernando.menezes@uniube.br
authors.forename: Fernando Carlos Hueb
authors.initials: FC
authors.lastname: de Menezes
authors.forename: Geraldo Thedei
authors.initials: GT
authors.lastname: Junior
authors.forename: Wildomar Jose
authors.initials: WJ
authors.lastname: de Oliveira
authors.forename: Tony de Paiva
authors.initials: Tde P
authors.lastname: Paulino
authors.forename: Marcelo Boaventura
authors.initials: MB
authors.lastname: de Moura
authors.forename: Igor Lima
authors.initials: IL
authors.lastname: da Silva
authors.forename: Marcos Boaventura
authors.initials: MB
authors.lastname: de Moura
mesh_terms: D001431:Bacteriological Techniques; D003188:Composite Resins / Q000737:chemistry; D003470:Culture Media; D003738:Dental Cements / Q000737:chemistry*; D004340:Drug Contamination; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D012995:Solubility; D013295:Streptococcus mutans / Q000502:physiology*; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003470:Culture Media; D003738:Dental Cements; D005899:Glass Ionomer Cements; D019279:Resin Cements; C090880:Vidrion F; C084550:Vitremer; D014867:Water; C069103:Dual Cement; D015036:Zinc Phosphate Cement