The importance of establishing a core outcome set for endodontic clinical trials and outcomes studies

Endodontic therapy aims to preserve teeth by preventing and treating apical disease, therefore, evaluation of treatment outcome in clinical trials and outcomes studies should effectively assess if it achieves these aims. Traditionally, treatment outcomes have been reported by clinicians after history and clinical examination in what is known as clinician-reported outcomes (CROs). Much less commonly employed however, are patient-reported outcomes (PROs) in which patients directly report on their condition. Endodontic treatment outcome reporting is evolving from a focus on CROs to increasing consideration for patient and disease-focused outcomes, with different criteria being proposed for assessment of treatment outcomes. Unfortunately, this has led to considerable variability and a lack of consensus on the definition, appropriate measurement and reporting of these outcomes. Heterogeneity in outcome reporting in clinical research provides a significant major barrier to conduct meta-analysis, guidelines development, clinical decision making, and ultimately affecting patient care. These effects could, however, be reduced by the establishment of a core outcome set (COS) in endodontics, which is defined as an agreed, standardized set of outcomes that should be included, measured and reported as a minimum in all trials and outcome studies. COS development is a regulated and validated process requiring involvement of appropriate stakeholders as well as a rigorous methodology. To date, COS has been developed for the management of traumatic dental injuries, orthodontic and periodontal treatment and is currently being developed for endodontic treatment. The aim of this review is to discuss the importance of COS in endodontics with focus on the evidence for and impact of heterogeneity in reporting endodontic treatment outcomes. An overview of an ongoing process for development of COS for different endodontic treatment modalities will also be provided.