Removing worn-out or painful old crowns requires great precision to avoid damaging the underlying healthy tooth tissue. Mechanical removers (gutators) that remove crowns by pulling them upwards are risky because they can cause the root of the underlying tooth to fracture or damage the bonds between the tooth and the bone. The safest modern technique involves completely splitting the crown’s surface in half vertically from the gum line to the incisal edge using special diamond or carbide burs (cutting removal). After the crown metal or zirconium is completely split, the crown is flexed to the sides using special levers, breaking the adhesive cement line that holds it to the tooth. In this way, the crown is safely removed from the tooth like a shell, without applying any tensile force or excessive vibration to the underlying abutment tooth.