The majority of pulpitis is caused by decay, when the cavity is particularly large, the bacteria inside will infect the pulp and cause inflammation, the nerve regeneration and repair ability is very weak, once the inflammation is infected, it is not curable. The infected pulp tissue can only be removed by root canal treatment, otherwise the inflammation will spread to the periapical bone tissue along the apical hole and cause more serious periapical inflammation. So when tooth decay occurs, go to the hospital for treatment in time, don’t wait for the decay to infect the nerve tissue and cause pain and then go for treatment, once the pulpitis is treated by root canal, the tooth will become brittle and easy to shatter, and need crown restoration if necessary.