Many patients in the clinic have such doubts and their complaints will be like this: this tooth used to hurt, but now it doesn’t hurt anymore, but it’s always uncomfortable to have a blockage, so please give me a filling directly from the doctor. In fact, this is a misconception that filling a tooth is a simple matter, where there is a hole can be filled. I do not know that every tooth is alive, a small tooth wrapped in a neurovascular cavity, and a hair-thin tube in each root. Most patients with pain later see teeth that have basically been decayed to the point where even the pulp chamber of the tooth has been exposed and the probing pain is very obvious, or even worse, the nerve vitality of the tooth has been lost and the dental film taken shows that there is already a clear inflammatory shadow around the root tip. Regardless of the degree of development, the common feature of these teeth is the presence of chronic inflammation, with a large number of anaerobic bacteria already breeding and multiplying in the neurovascular channels of the tooth or around the root, waiting for the opportunity to trigger the next acute attack. The consequences of going for a filling when the tooth is already boarded with bacteria can be imagined. These anaerobic bacteria prefer a dense and less oxygenated environment, and once the channels with the outside world are filled with filling material, these bacteria will continue to multiply in large numbers, leading to acute inflammation of the tooth in the short term. Based on the special anatomical structure of teeth, it is correct to remind all patients to check their teeth regularly in hospital to check the existence of caries, and when the scope of caries is small without accumulating pulp, it is possible to fill the caries directly, the more shallow caries, the better the healing is, not only avoiding the adverse reaction brought by root canal treatment, but also avoiding the expensive medical expenses. All in all, it still proves the famous saying: disease is prevention.