Dentist Finds 4-Inch Nail in Man\'s Skull A Colorado man who went to his dentist for a toothache discovered that he had a 4 inch nail in the roof of his mouth. Almost a week earlier the man's nail gun backfired sending a nail through a piece of wood, but unknown to the man a second nail had shot through his mouth. Over the next week the individual thought he had a toothache and had been using ice and painkillers to ease the pain. He finally sought help from his dentist who discovered the nail. All I can say is OUCH! Can you imagine not knowing or feeling the nail itself? B.