You probably don't need to steal a corps, fake it's teeth, arranging a fiery carcrash at the bottom of a cliff. You need to vanish and leave behind some hints for the authorities enough to make them think you're probably dead. Maybe hinting you drowned in a river would be easy, especially if it's fast. Just leave clothes and papers on the bank as if you were went swimming. Maybe some stuff as if you had an outing or something.