title: pH and effects on Streptococcus mutans growth of denture adhesives: an in vitro study.
abstract: OBJECTIVE
  To evaluate the pH and effects on Streptococcus mutans growth of denture adhesives.
  
  
  BACKGROUND
  There is little information regarding the pH of contemporary adhesives and their influences on S. mutans growth.
  
  
  METHODS
  The adhesives tested were Polident® cream, Protefix® cream and Protefix® powder. Samples of each adhesive were added to deionized water to produce solutions of 10.0, 5.0, 2.5 and 1.0% w/v (cream formulations) or 5.0, 2.5,1.0 and 0.5% (powder formulation). The pH values were measured immediately after preparation and at 1-, 2-, 3-, 6-, 12-, and 24-h intervals using a digital pH meter. Streptococcus mutans UA159 was inoculated in the Brain Heart Infusion medium with or without the adhesive extracts (control). Bacterial growth was observed by measuring absorption at 600 nm every 1 h for 12 h using a spectrophotometer.
  
  
  RESULTS
  The tested adhesives generally remained relatively pH-stable over 24 h, ranging from 5.5 to 7.0. There were no statistically significant differences in S. mutans growth rates between the extract-treated and control cultures (p>0.5).
  
  
  CONCLUSIONS
  Some adhesives produce a pH below the critical pH of hydroxyapatite and may not be suitable for patients with natural teeth. None of the tested adhesives significantly affect S. mutans growth.
authors.affiliation: Key Lab for Oral Biomedical Engineering of Ministry of Education, School of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Fengying
authors.initials: F
authors.lastname: Chen
authors.forename: Tiantian
authors.initials: T
authors.lastname: Mao
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Cheng
mesh_terms: D000269:Adhesives / Q000737:chemistry*; D000464:Alginates / Q000737:chemistry; D002735:Chlorophyllides / Q000737:chemistry; D003781:Denture Retention; D006801:Humans; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000737:chemistry; D008298:Maleates / Q000737:chemistry; D008422:Materials Testing; D009824:Ointments; D010226:Parabens / Q000737:chemistry; D010577:Petrolatum / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry; D011208:Powders; D013053:Spectrophotometry; D013295:Streptococcus mutans / Q000254:growth & development*; D013997:Time Factors
chemical_list: D000269:Adhesives; D000464:Alginates; D002735:Chlorophyllides; D062385:Hydroxybenzoates; D008298:Maleates; D009824:Ointments; D010226:Parabens; D011095:Polyethylenes; D011208:Powders; D010577:Petrolatum; C043105:poly(methyl vinyl ether-co-maleic anhydride); C007020:chlorophyllin; C038193:4-hydroxybenzoic acid