You write that capping aka known as crowning teeth is not good unless the tooth is a strong one . Capping a tooth will make any tooth weak and succeptible to nerve death , resulting in root canals (which cause chronic infection ) and eventually extraction.When dentists crown teeth , they file them down to almost nothing and this is the worst thing you can do to a tooth if you want that tooth in your mouth your whole life . In virtually all cases where the dentist claims you need a crown , you can get a filling (not Amalgam ) or an onlay instead.Your teeth will last the longest if you keep as much tooth structure as possible . Dentists want you to get crowns instead of fillings because crowns are very expensive.