title: Preliminary investigation of bacteremia incidence after removal of the Haas palatal expander.
abstract: BACKGROUND
  The aim of this study was to investigate the presence of bacteria in the bloodstream immediately after removing Haas palatal expanders; this could be considered an invasive procedure.
  
  
  METHODS
  Eight patients (18.5 +/- 3.9 years old) wearing Haas palatal expanders had 5-mL blood samples taken immediately before and 10 minutes after removal of the apparatus. The blood was aseptically inoculated into hemoculture bottles and incubated at 37 degrees C for 7 days. Medium alterations suggesting bacterial growth were investigated by using Gram staining.
  
  
  RESULTS
  Bottles containing blood taken before apparatus removal did not show bacterial growth. However, 4 of the 8 postremoval blood samples showed turbidity after 5 days, and bacterioscopy analysis showed Gram-positive cocci. Subsequent cultures in blood-agar medium plates allowed classifying the bacteria as viridans streptococcus.
  
  
  CONCLUSIONS
  There is a strong possibility that trauma after removing Haas expanders might be correlated to transitory bacteremia, thereby implying the need for a more careful approach when dealing with special patients, such as those at risk of cardiopathic complications.
authors.affiliation: Laboratory of Stomatology, Dental Branch, Pontifical Catholic University of Paraná, Curitiba, Brazil. edvaldo.rosa@pucpr.br <edvaldo.rosa@pucpr.br>
authors.forename: Edvaldo Antonio Ribeiro
authors.initials: EA
authors.lastname: Rosa
authors.forename: Rodrigo Nunes
authors.initials: RN
authors.lastname: Rached
authors.forename: Orlando
authors.initials: O
authors.lastname: Tanaka
authors.forename: Felipe
authors.initials: F
authors.lastname: Fronza
authors.forename: Francisco
authors.initials: F
authors.lastname: Fronza
authors.forename: Roberley
authors.initials: R
authors.lastname: Araújo Assad
mesh_terms: D000293:Adolescent; D000328:Adult; D016470:Bacteremia / Q000209:etiology* / Q000382:microbiology; D002648:Child; D017005:Dental Debonding / Q000009:adverse effects; D006801:Humans; D009967:Orthodontic Appliances / Q000009:adverse effects*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D013290:Streptococcal Infections / Q000209:etiology* / Q000382:microbiology; D019533:Streptococcus oralis / Q000302:isolation & purification