Self-interest, moralists suggest, strongly influences people's behavior. To test the possible effect on dentists, we asked four groups--oral surgeons, periodontists, general practitioners, and orthodontists--to evaluate the need for removal of third molars in three cases. As expected, oral surgeons, who had the most to gain, recommended extraction at a significantly higher rate than the other groups. We found a direct hierarchical relationship between the degree of surgical orientation of a group and its likelihood to see a need for extraction.