A crown is best if the tooth being treated is damaged or has a cavity. It restores and preserves the tooth and covers it like a cap. Veneers are thin layers of porcelain, resin, or other material placed over the front of the tooth for cosmetic reasons. They can be effective for correcting minor chips and improving the appearance of your teeth but do not affect the function of the teeth. If your teeth are damaged or have a cavity, crowns are the best choice.