INTRODUCTION: Coronal sealing, quality of root canal treatment, and periapical status have been widely investigated. However, which of two practitioner-dependent determinants (endodontic treatment or coronal restoration) is the most important to the periapical status remains scientifically debated. OBJECTIVES: This study investigated the relative importance of the technical qualities of root canal filling and marginal sealing of the coronal restoration on the periapical status and screened previously published data. METHODS: A retrospective study collected and analyzed clinical and radiological data on 246 endodontically-treated teeth. Six paired comparisons were carried out between groups combining good or poor endodontic treatment (G/P E) with good or poor coronal restoration G/P R). Results are displayed through forest plots of odds ratios for each comparison.RESULTS: In the retrospective study, the endodontic determinant seems to be more important than the restorative one (37.5% of diseased periapical status with GE versus 41.2% with PE). In the systematic review, odds ratio analyses showed that group GE+GR had 1.7 less periapical lesions than group PE+GR and 2.7 less lesions that group PE+PR. Belonging to group PE+PR was found significantly associated with ‘diseased’ periapical status. CONCLUSION: The retrospective study and the systematic review agreed that endodontic treatment (precisely, root canal filling) was found more important than coronal restoration (precisely, marginal sealing) for healthy periapical tissue.