My dentist placed a zirconia crown with porcelain overlay on an upper back molar. When I went in to get the bite adjusted, the dentist removed some of the material from the crown but also ground off some of the healthy tooth below it (the one that makes contact with the crown). He only took a small amount of the healthy tooth but it left the edge sharper than it was. What I want to know: Is it normal procedure to remove part of a healthy tooth in order to get a crown to fit?