most crowns can last up to 15 years depending on the type of material used for making crown. sometimes crown replacement is neccessary when there is excessive wear or fracture in crown or there are complications due to tooth decay. so if that is the reason why that dentist suggested you crown replacement then it is neccessary. otherwise if the crown is fine and it is kept plaque free then no need to replace it. for further information consult a dentist online --> <link>
is it necessary to replace my tooth crown after 9 years?