BACKGROUND: This study aimed to investigate the effect of unintentional AH Plus sealer extrusion on the outcome of nonsurgical root canal treatment and retreatment in teeth with apical periodontitis (AP) compared to teeth with AP and no sealer extrusion at the 1-year follow-up.
METHODS: In a retrospective case-control study conducted from September 2016 to September 2021, teeth presenting clinical and radiographic signs of AP prior to treatment were included. The study comprised 2 groups: AH Plus sealer extrusion group (n = 60): initial root canal treatment or nonsurgical retreatment with unintentional apical extrusion of AH Plus sealer; and no AH Plus sealer extrusion group (n = 60): underwent the same treatment types without sealer extrusion. Additional factors, including sex, age, tooth type, tooth location, and treatment type, were recorded as potential outcome predictors. At 1-year follow-up, teeth were evaluated clinically and radiographically, and outcomes were classified as favorable (healed/healing) or unfavorable (uncertain/non-healing). Statistical analyses, such as the χ2 test, logistic regression, and Mann-Whitney U test, were employed for data analysis.
RESULTS: A favorable outcome was observed in 88.4% and 85% of the cases of the AH Plus sealer extrusion and no AH Plus sealer extrusion groups, respectively. There was no statistically significant difference between the groups in terms of outcomes (P > .05) when analyzed categorically or ordinally. Of independent variables, nonsurgical retreatment showed lower healing of AP in both groups.
CONCLUSIONS: Unintentional AH Plus sealer extrusion did not affect the healing of AP. However, initial root canal treatment showed better healing of AP than nonsurgical retreatment in the presence of AH Plus sealer extrusion. The analyzed outcome predictors had no effect on treatment outcome.

BACKGROUND: The purpose of the current population-based study was to analyze the 5-year survival rate of teeth that received nonsurgical endodontic treatment. Specifically, the variables affecting the 5-year survival rates of endodontically treated teeth were analyzed.
METHODS: The present study included all endodontically treated teeth reported in 2010 in the National Health Insurance Cohort database of the Republic of Korea. By tracing the dental records of the sample to the end of 2015, the 5-year survival rates of the initial root canal treatment (RCT) and re-RCT were analyzed. Gender, age, institution type, diagnosis, arch type, tooth type, number of visits, and rubber dam usage were included in the analyses as confounding variables.
RESULTS: In total, 2,866,749 teeth received initial RCT, and 173,429 teeth received re-RCT. Five-year survival rates were 90.85% and 88.42%, respectively. The survival rate of teeth that received initial RCT was significantly higher than that of those that received re-RCT. Specifically, re-RCT showed a significantly higher rate of extraction within 12 months than during other intervals. Furthermore, the following characteristics significantly positively affected the 5-year tooth survival rate: being female, <20 years of age, hospital as the institution type, mandibular teeth, anterior teeth, initial RCT, and use of rubber dam.
CONCLUSIONS: Because of its high 5-year survival rate, endodontic treatment is an effective method for maintaining natural teeth.

BACKGROUND: It is well-known that the usage of rubber dams during root canal treatment (RCT) improves infection control and treatment efficacy and protects patients. However, the effect of rubber dam usage on endodontic outcomes remain uncertain. The aim of the present study was to investigate whether rubber dam usage affects the survival rate of initial RCT using a nationwide population-based database.
METHODS: A total of 517,234 teeth that received initial RCT between 2005 and 2011 met the inclusion criteria and were followed until the end of 2011. Univariate and multivariate Cox proportional hazards models were used to estimate the effects of rubber dam usage on the risk of tooth extraction after initial RCT.
RESULTS: Of the 517,234 teeth, 29,219 were extracted, yielding a survival rate of 94.4%. The survival probability of initial RCT using rubber dams after 3.43 years (the mean observed time) was 90.3%, which was significantly greater than the 88.8% observed without the use of rubber dams (P < .0001). After adjusting for age, sex, tooth type, hospital level, tooth scaling frequency per year after RCT, and systemic diseases, including diabetes and hypertension, the tooth extraction hazard ratio for the RCT with rubber dams was significantly lower than that observed for RCT without rubber dams (hazard ratio = 0.81; 95% confidence interval, 0.79-0.84).
CONCLUSIONS: The use of a rubber dam during RCT could provide a significantly higher survival rate after initial RCT. This result supports that rubber dam usage improves the outcomes of endodontic treatments.