The prosecutor's office in Aruba said that an analysis based on dental records rules out that the bone fragment came from Holloway.
The jawbone was confirmed to be human, but it is unclear who it belongs to.
Holloway disappeared in 2005 while on a high school graduation trip. She was last seen leaving a bar with Dutchman Joran van der Sloot, who is the prime suspect in her disappearance.
The Associated Press contributed to this story.