There are many factors that can influence the success rate of root canal treatment, and the range varies depending on specific circumstances. Some studies report success rates between 60% and 70%, while others indicate rates as high as 80% to 90%. The key factors are the condition of the affected tooth and the quality of the doctor's treatment.

First, the degree of infection in the tooth is a critical factor. If the pulpitis is in its early stages and the infection is limited to the crown, with no bacteria having entered the root canal, the success rate can be very high as long as the doctor avoids introducing infection into the root canal during the procedure. Some foreign studies report a two-year success rate of up to 94% in such cases. If bacteria have already entered the root canal system but have not yet adhered to the canal walls or invaded the dentinal tubules, lateral canals, or apical ramifications, treatment may still yield good results. However, if bacteria have penetrated the dentinal tubules, lateral canals, apical ramifications, and the periapical region, the demands on the doctor’s technical skills, treatment environment, and equipment are much higher, and the success rate may not be as high as in cases of less advanced infection.

The primary goal of root canal treatment is to control and eliminate infection within the root canal system, maintaining it in a sterile state. If bacteria remain in the root canal, they may spread through the apical foramen to the periapical tissues, leading to reinfection and treatment failure. Therefore, the key to success is whether the infection in the tooth’s root canal system is effectively controlled and managed.

To ensure a higher success rate, early detection and treatment are crucial. Prompt, standardized root canal treatment can provide better results and higher success rates. In addition to the infection, the complexity of the tooth’s anatomy is another important factor. If the root canal structure is relatively simple, infection control is usually more effective, leading to more satisfactory treatment outcomes. However, if the tooth has curved or narrow roots, or if there are lateral canals and apical ramifications, the technical demands on the doctor and the medical equipment are significantly higher. In cases where bacteria have invaded these complex areas, even modern technology may not always produce ideal results.

Therefore, even with the same type of pulpitis or periapical disease, treatment by the same doctor may not always guarantee the same outcome in different cases.