Braces generally refer to crowns. Teeth with cracks after root canal treatment are generally recommended to be protected with a crown to prevent further destruction of the tooth, thus preserving the healthy remaining tissues, depending on the condition of the tooth that has not undergone root canal treatment. Cracks in teeth are usually caused when the root canal treated tooth bites on hard objects. The root canal treated tooth loses its nutrient supply from the pulp and the enamel becomes brittle, which is prone to splintering when it bears a large biting force. If the tooth has a very shallow crack and has not had a root canal, and this tooth is asymptomatic, the shallow crack is usually ground away and filled with a resin material. If this tooth is experiencing spontaneous pain, nighttime pain, or severe pain, it generally suggests that the pulp has been affected, at which point we will need to do a root canal and then crown the tooth. To summarize, if this tooth has undergone root canal treatment, then it is necessary to make a crown to protect it, if the tooth is healthy and asymptomatic, it can be observed first, or filled with resin material.