The correct term for tooth decay should be caries, caries pain does not necessarily have to do root canal treatment, if it is deep caries without spontaneous pain, there is no need to do root canal treatment, if the affected tooth has already appeared symptoms of pulpitis, it is necessary to do root canal treatment, as follows. 1. Deep caries: For deep caries without spontaneous pain, not serious excitation pain, no delayed pain after removing the stimulus, and the pulp is basically normal, the cavity can be prepared, the bottom of the pad to protect the pulp, and complete the resin filling treatment. 2. Pulpitis: If the affected tooth already has symptoms of pulpitis such as spontaneous pain, hot and cold stimulation pain, root canal treatment is needed to remove the inflamed pulp and then fill the root canal tightly, followed by resin filling treatment for the tooth. It is recommended to go to the hospital in time to receive regular treatment as soon as possible.