Cracked teeth are likely, caused by the following causes: First, the patient has been traumatized, the patient is recalled that he or she has bitten hard objects or suffered trauma, resulting in loose or cracked teeth, this time if the crack is not obvious, you can temporarily observe, but if the crack is very obvious need to protect the porcelain crown, if the subsequent emergence of the root splitting also need to extract the The affected tooth. Secondly, the tooth cracks because the patient is sleeping, there is a more serious grinding of teeth caused by this time can consider the braces to protect the teeth. Wearing a clear brace before sleep can be a good way to protect the teeth from severe grinding, which can lead to hidden cracks in the teeth. Third, cracks are caused by teeth with dead pulp that have not been restored with porcelain crowns after undergoing root canal treatment. Because the dead pulp teeth lost the nutrient supply of blood vessels, its own toughness is poor, easy to lead to the occurrence of fracture.