Root canal therapy is now an internationally recognized effective method for treating endodontic and periapical disease, greatly improving the chances of tooth preservation. Root canal treatment (commonly known as nerve extraction or root extraction) is the removal of inflamed or necrotic tissue from the pulp chamber and root canal of a tooth, disinfection and sealing the root canal tightly to avoid reinfection of the root canal of the tooth, thus preventing tooth pain and restoring tooth function. After root canal treatment, the tooth needs to be followed up with restorative dental treatment. There are two general methods of restorative dentistry: one is to fill the defective part of the tooth directly with filling material; the other is to protect the tooth by placing a brace on the outside of the tooth. Direct filling is simple and convenient, with fewer follow-up visits and lower costs, but it is not durable and there is a risk of tooth splitting. Many patients think that if they don’t eat hard things, their teeth will not split, but they often see cases of splitting after treatment without braces, and some teeth with deeper splits have to be extracted, which is a great pity. Therefore, after the root canal treatment, the doctor will usually recommend the patient to have braces to protect the affected tooth. Although braces are more frequent and expensive, they can protect the remaining tooth tissue, prevent the tooth from splitting and restore the normal chewing function of the tooth. Another more important function of braces after root canal treatment is to prevent bacteria from entering the treated pulp and root canal through the tiny cracks between the filling material and the tooth tissue, which can cause inflammation and lead to treatment failure. Having a brace, on the other hand, creates a good seal and effectively ensures the long-term results of the root canal treatment. Therefore, the best treatment plan is to protect the tooth with braces after root canal treatment. Why are teeth after root canal treatment more prone to fracture than healthy teeth? There are two main reasons for this. Most teeth with diseases such as pulpitis and periapical periodontitis that require root canal treatment have been destroyed, and the amount of remaining tooth tissue in the tooth is less and less resistant. In addition, after root canal treatment, the tooth loses the nutritional supply from the pulp, causing the tooth to become more brittle and prone to splitting, just like a dead tree, which breaks easily. Teeth have to bear certain force when chewing food, especially the back teeth, which may have to bear hundreds of pounds of force when chewing, and thus are prone to tooth splitting, and once the tooth is split deeper, it needs to be extracted, wasting the time and expense previously spent. The risk of tooth splitting can be greatly reduced by timely braces on the teeth after root canal treatment, ultimately achieving the goal of preserving one’s own teeth.