Al–Nuaimi N, et al. – A pooled analysis of the data obtained from three previous prospective clinical outcome studies was undertaken to provide an estimate of the proportion of successful outcomes of primary and secondary root canal treatments (retreatments) determined by periapical radiographs and cone beam computed tomography (CBCT). It was found that the proportions of favourable outcomes of primary root canal treatments and retreatments assessed with CBCT were lower when compared to periapical radiographs, and also lower than those historically reported by periapical radiograph–based outcome studies.