title: Effect of chlorhexidine mouth rinse on Streptococci counts of tooth-tissue-borne palatal expander biofilm.
abstract: OBJECTIVE
  To assess total Streptococci (TS) counts and biofilm mass over tooth-tissue-borne palatal expander (TTBPE), as well as the effect of chlorhexidine (CHX) mouth rinse on these variables.
  
  
  METHODS
  A cross-sectional study design employed clinical procedures and laboratorial techniques.
  
  
  METHODS
  Patients who had TTBPE removal indicated were divided into two groups: a CHX group (n = 26) in which three times a day of 0.2% CHX digluconate mouth rinses were prescribed 7 days before TTBPE removal; and a control (CON) group (n = 25) in which no antimicrobial treatment was applied.
  
  
  METHODS
  'Gender', 'Age', and 'TTBPE wear time' were recorded. After TTBPE removal, biofilm mass was determined by the difference between (TTBPE + biofilm) and (TTBPE only) masses. TS counts were determined by biofilm suspension followed by progressive dilutions and culture on Mitis Salivarius agar with incubation at 37 degrees C for 72 h.
  
  
  METHODS
  Biofilm mass (mg) and Colony Forming Units of TS / mg of biofilm (CFU-TS / mg) were calculated. Results - Total Streptococci mean values in CHX (6.77 x 10(6)CFU-TS / mg) were statistically lower (p < 0.01) than those in CON (3.82 x 10(7)CFU-TS / mg), but there was no statistical difference (p > 0.05) between CHX (168.88 mg) and CON (182.04 mg) masses nor statistical correlation (p > 0.05) between biofilm mass and CFU-TS / mg in the two groups.
  
  
  CONCLUSIONS
  Chlorhexidine reduces the TS counts in TTBPE, but has no effect on biofilm mass.
authors: Pontifical Catholic University of Paraná, Curitiba, Brazil. ivan_maruo@yahoo.com.br
authors: I T
authors: IT
authors: Maruo
authors: E A R
authors: EA
authors: Rosa
authors: H
authors: H
authors: Maruo
authors: O
authors: O
authors: Tanaka
authors: O
authors: O
authors: Guariza Filho
authors: S A
authors: SA
authors: Ignácio
authors: E S
authors: ES
authors: Camargo
mesh_terms: D000293:Adolescent; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002648:Child; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D015169:Colony Count, Microbial; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009067:Mouthwashes / Q000494:pharmacology*; D009967:Orthodontic Appliances / Q000382:microbiology*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D013291:Streptococcus / Q000187:drug effects*
chemical_list: D000891:Anti-Infective Agents, Local; D009067:Mouthwashes; C010882:chlorhexidine gluconate; D002710:Chlorhexidine