Assessment of Case Complexity of Root Canal Treatments Using Contemporary Complexity Grading Systems: A Clinical Service Evaluation.

Aim: To assess the complexity of root canal treatments allocated to Postgraduate Endodontology trainees at Cardiff University Dental Hospital (CUDH) using the English Clinical Standards for Restorative Dentistry (ECS) in comparison with the Dental Practicality Index (DPI), the EndoApp (EA), and the Endodontic Complexity Assessment Tool (E-CAT).

Material and methods: Two-hundred-and-one case records were evaluated by two calibrated examiners using each complexity assessment system. Inter-examiner and intra-examiner variability was calculated using Cohen's kappa coefficient. Statistical analyses compared the scores obtained for the same case using the different systems.

Results: Most cases were assigned level 3 complexity using ECS, EA and E-CAT (82%, 92% and 74.1%, respectively), and scores of 3-5 (78.6%) using DPI. EA consistently assigned higher complexity scores compared with ECS and E-CAT. E-CAT assigned lower complexity scores compared with ECS. A statistically significant moderate-substantial level of agreement was demonstrated between E-CAT and ECS (weighted kappa = 0.647 [95% CI: 0.517 to 0.776], p < 0.001). A statistically significant fair level of agreement was demonstrated between EA and ECS (weighted kappa = 0.290 [95% CI: 0.113 to 0.466], p < 0.001) and EA and E-CAT (weighted kappa: 0.385 [95% CI: 0.226 to 0.544], p < 0.001). A statistically significant weak positive correlation was found between DPI and ECS [Spearman's correlation coefficient (r_s) = 0.202, p = 0.004], DPI and EA (r_s = 0.344, p < 0.001), and DPI and E-CAT (r_s = 0.364, p < 0.001). The most common cause of increase in complexity scores was 'canal negotiability' for ECS (47%) and the 'endodontic treatment need' for DPI (84.1%). The unknown algorithm used by EA and E-CAT prevented the identification of specific factors that contributed to the endodontic treatment complexity.

Conclusion: The majority of cases treated at CUDH were of high complexity. E-CAT assigned slightly lower complexity scores compared with ECS and EA, potentially due to its detailed assessment of factors. A weak positive correlation was found between the complexity grading systems. DPI's broader assessment justifies a cut-off score of 3 for specialist referral due to the increased agreement with ECS, E-CAT and EA at this threshold.