Most of the nutrition of the tooth comes from the supply of the vascular nerve of the pulp. After root canal treatment, the nerve vessel of the pulp will not be able to supply nutrition, and the tooth will become brittle. When subjected to a large biting force, without the buffer of the originally elastic dentin, it will easily cause stress concentration, resulting in tooth fracture. When a tooth fracture occurs, once the fractured and loose part of the tooth piece is broken too deep below the gum, it is often impossible to retain it, and the entire tooth can only be extracted as a whole! Many of the patients encountered in clinical practice come in after a tooth has fractured because they did not utilize a crown restoration in a timely manner after root canal treatment. Most of the teeth that need to do root canal treatment are decayed teeth, and the remaining tooth tissue is very little. After the root canal treatment, if the tooth is restored by crown directly, it cannot bear the normal chewing force, so it usually needs to be restored by pile crown. The so-called pile crown restoration is a method that uses the root of the tooth that has already undergone root canal treatment to fix the root and use the nucleus of the pile core to restore part of the defective tooth, and then make a crown. This is the most commonly used treatment method in clinical practice. Generally, pile crown restoration can be considered one week after root canal treatment, and this treatment plan is more mature and has a higher success rate. The pile crown restoration of the tooth after root canal treatment effectively protects the remaining tooth tissue from splitting. If the root canal is not crowned and the tooth is split and cannot be retained, only a removable denture, fixed denture, or implant denture can be considered. The biggest advantage of a removable denture is that it removes less tooth tissue, but it needs to be worn repeatedly and is not easy to maintain oral hygiene, has a greater sense of foreign body, and has poor aesthetics and chewing efficiency. Fixed bridge is a fixed restoration method using the neighboring teeth on both sides as a retainer. The completed denture is more consistent with the original size and color of the teeth, which is aesthetically pleasing and comfortable, but more dental tissues need to be removed and the cost is higher than the removable denture. The implant denture does not require the removal of adjacent dental tissues, it is fixed by using implant pins that are implanted into the jawbone and integrated with the bone, it has most of the advantages of a fixed denture, but it is also more expensive and there are no periodontal nerve fibers around the pins to sense the chewing pressure, and it requires higher oral hygiene. In contrast, a pile crown restoration that preserves the root of the tooth is the most suitable option. Although the number of follow-up visits required for pile crown restoration after root canal treatment is high, it is well worth it. Although the tooth is not nourished by the pulpal nerve after root canal treatment, there are periodontal nerve fibers around the root, which can sense the chewing pressure and prevent the tooth or restoration from being damaged by excessive biting force. Moreover, the treatment cost of crown restoration in time is lower than the cost of extracting a tooth and then fixing it, and the pain is also less. Therefore, we would like to remind all patients that if you have had root canal treatment and have not had a crown restoration, please go to the hospital in time and do not wait until the tooth is fractured and then regret it. Love your teeth, try to save your teeth, and keep the roots.