Sometimes a cavity can destroy the tooth to the extent that a filling may no longer be the best choice, or a nerve treatment has to be performed. In these cases it is best to surround the tooth with a dental crown. Crowns are also recommended for children who may be at high risk for further decay. Dental crowns are placed by removing the cavity and shaping the tooth surface with dental instruments so that the crown can fit on it. Dental cement is then used to hold the crowns in place. Stainless steel and white crowns are now available.