RESUMO
AIM: To assess the effectiveness of the Dental Practicality Index (DPI) in predicting the outcome of root canal retreatment in posterior teeth. METHODOLOGY: One hundred and thirty-seven posterior teeth with symptoms and/or signs of post-treatment endodontic disease requiring root canal retreatment and previously included in a clinical trial were selected. Clinical and radiographic examinations including digital periapical and cone beam computed tomography (CBCT) were obtained pre-treatment and 1-year postoperatively from a previous study. Two calibrated and trained assessors who were unaware of the treatment outcome assessed the pre-treatment clinical records of these cases using the DPI. The DPI score was then compared to the outcome of the root canal retreatment. A Chi-square/Fisher's exact test was used to establish a relationship between categorical variables, the total score of DPI vs outcome. RESULTS: Retreated teeth with DPI scores equal to 6 or above had an unfavourable outcome of 50% vs 14% of teeth with DPI below 6. Teeth with DPI score equal to 3 or above had an unfavourable outcome of 23% versus 2%, for teeth below 3. Molar teeth with a DPI score below 3 had a favourable outcome percentage of 96%. CONCLUSIONS: This study highlighted that using the DPI gave a good outcome prediction for root canal retreatments. However, further research, including the prospective assessment of a wider range of cases undertaken by a larger group of examiners is needed to further validate the DPI.
