Purpose: to investigate the effect of periodontal status of a tooth at the time of NSRCT and the role of supportive
periodontal treatment on the survival rate of ETT.
•N= 315 , all mature permanent molars that had received NSRCT at the endodontic department performed by postgraduate students from January 1, 2008, and January 1, 2017.
•Patients’ records, radiographs, and computerized databases were retrospectively examined and the inclusion criteria were : Patients between 18 and 75 years of age in good health , an acceptable quality of NSRCT , ETT with a preoperative diagnosis of irreversible pulpitis in order to standardize the results of the data , ETT with complete periodontal charting before NSRCT including pocket depths and clinical attachment loss, degree of mobility, and radiographic bone loss , restorable teeth with adequate ferrule effect and adequate crown within 3 months after NSRCT
•Exclusion criteria were : vertical root fracture and any operative mishaps such as a perforation and a separated file
•Included ETT were divided into 3 groups
1. ETT with no periodontal disease at the time of NSRCT (healthy/control group, n = 125)
2. ETT diagnosed with mild periodontitis (mild group, n = 100)
3. ETT diagnosed with moderate periodontitis (moderate group, n = 90) ( Table 1)
• In this 9-year retrospective study, 20 ETT 6.3%were extracted, and 295 93.7% survived to the end of the follow-up
•Three factors that were significantly correlated with the survival of the ETT were as follows: periodontal diagnosis, SPT provided after RCT , and smoking. (Table 2)
• The 9-year survival rate after NSRCT was 90% for teeth with a healthy periodontium at the time of NSRCT. For ETT with mild periodontitis, the 9-year survival rate after NSRCT was 71%. Also, teeth with moderate periodontitis showed the lowest 9-year survival rate at 59%. This difference was statistically significant between groups
Maintain good OH and receive SPT after NSRCT can significantly affect the survival rate of ETT.