2TheApex: Roughly 10%One statistic you may want to share with patients is that 1 in 10 teeth with crowns end up requiring root canal therapy. Here is the Study. Not a bad statistic for patients to know prior to a crown prep. There is always a risk. The more highly the tooth is restored increases the chances.http://endolit.com/betaadmin/uploads/A_Prospective_Study_of_the_Incidence_of_Asymptomatic_Pulp_Necrosis_Following_Crown_Preparation.pdf