To investigate the prevalence of different primary reasons for endodontic referrals and the clinical symptoms of the referred cases.

Clinical data of total endodontic treatment cases (1,014 teeth) including endodontic referral cases (224 teeth) between January 1, 2010 and December 31, 2012, at Kangdong Sacred Heart Hospital, were investigated retrospectively. The one major reason for referral, the clinical symptoms, and the resulting treatment procedures of referral cases were recorded. The percentages of clinical symptoms of the endodontic referral cases and the total endodontic treatment cases were compared by χ² test for each symptom.

Persistent pain was the most frequent reason for endodontic referral (29.5%), followed by presence of gingival swelling and sinus tract (24.1%), and apical radiolucency (12.9%). Referrals in cases involving endodontic difficulties such as canal calcification, broken instruments, post, perforation, and resorption were less than 5.0%, respectively. The percentages of four major clinical symptoms of pain, apical radiolucency, previous endodontic treatment, and gingival swelling and sinus tract were significantly higher in the endodontic referral cases than those in the total endodontic cases (p = 0.001). Among the included referral cases, 72.8% were treated with nonsurgical endodontic treatment only. Teeth other than the referred teeth were diagnosed as the origin of the problem in 5.8% of the referrals.

The high prevalence of pain, apical radiolucency, previous treatment, and gingival swelling and sinus tract in endodontic referral cases suggest that these symptoms may be what general practitioners consider to be difficult and refer to endodontists.

This study aimed to assess prospectively the clinical outcome of nonsurgical endodontic treatment and identify patient- and tooth-related factors, rather than treatment-related factors, that were the best predictors of this outcome.

The inception cohort comprised 441 teeth (320 patients) and 175 teeth (123 patients) were followed up for 1-2 years. Age, gender, presence of medical disease, number of canals, previous endodontic treatment, presence of sensitivity and pain, pulp vitality, swelling or sinus tract of pulpal origin on the gingiva, periapical radiolucency and tendency of unilateral bite on the affected tooth were recorded at treatment start.

The outcome was classified on the basis of periapical radiolucency as healed or non healed. The overall healed rate in these cases, including nonsurgical retreatment, was 81.1%. Four tooth-related factors had a negative impact in the bivariate analysis: previous endodontic treatment, necrotic pulp, preoperative gingival swelling or sinus tract of pulpal origin, and preoperative periapical radiolucency. Stepwise logistic regression analysis including patient-, tooth-related factors and level of the root canal filling as a treatment-related factor showed that preoperative gingival lesion (odds ratio [OR]: 4.4; p = 0.005), preoperative periapical radiolucency (OR: 3.6; p = 0.011), and ≤ 1-2 mm under root filling length (OR: 9.6; p = 0.012) were significant predictors of failure.

A preoperative gingival lesion of pulpal origin can influence the outcome of nonsurgical endodontic treatment in addition to preoperative periapical radiolucency.