Deep caries to pulp means that the development of caries has progressed from deep caries to reversible pulpitis, or directly to the state of pulpitis. In this case, it is necessary to go to the professional dentistry department as soon as possible for decay and pulp pacification, or direct root canal treatment of the pulp. Generally, with the gradual development of caries, if the deep caries is not treated as soon as possible, it will soon develop into the state of reversible pulpitis. If the pain is significantly reduced until it disappears, it means that the pulp is recoverable, then there is no need to carry out root canal treatment, and it is enough to fill the deep caries directly. However, if the tooth continues to be painful after being soothed, it means that the deep caries has developed to the state of definite pulpitis, then only root canal treatment of the pulp can be performed for the tooth, and then the tooth can be protected by applying crown restoration, which is the treatment method for pulpitis.