McIlroy, who has been a patient of Belfast dentist Dr. Mark Conroy for many years, was defending his title in a Palm Gardens, FL, tournament when he withdrew midround, according to a story in the Belfast Telegraph.
Dr. Conroy notified the Pro Golfer's Association (PGA) about McIlroy's ongoing third molar problems.
McIlroy said he couldn't concentrate because of "severe wisdom tooth pain." He was 7 over par after eight holes. McIlroy said the tooth was due to come out soon and he took Advil to relieve the pain the previous night, but the pain returned in the morning.
According to golf rules, a player cannot quit unless there is the threat of lightning or "some other good reason such as sudden illness." A golfer who quits must provide written evidence of his illness to the PGA within two weeks or face a fine or ban.