Preliminary investigation of bacteremia incidence after removal of the Haas palatal expander.

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.