Charlie Sheen (WENN.COM)A police investigation has been launched into allegations Charlie Sheen was involved in a bust-up during a trip to the dentist last week.Officers of the Los Angeles Police Department are investigating claims the Anger Management star scuffled with his personal dentist and an oral surgeon while he was in the chair receiving treatment for an abscess.TMZ reports after the actor allegedly assaulted a dental technician after a mask was put over his face to administer nitrous oxide and then pulled a knife on his dentist. The dentist was not hurt.According to website, cops want to interview Sheen and his dentist before referring the case to the Los Angeles County District Attorney, who will decide whether to prosecute the TV star on charges of battery and felony assault.