Case reports can provide early information about new, unusual or rare disease(s), newer treatment strategies, improved therapeutic benefits and adverse effects of interventions or medications. This paper describes the process that led to the development of the Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020 guidelines through a consensus‐based methodology. A steering committee was formed with eight members (PD, VN, BC, PM, PS, EP, JJ and SP), including the project leaders (PD, VN). The steering committee developed an initial checklist by combining and modifying the items from the Case Report (CARE) guidelines and Clinical and Laboratory Images in Publications (CLIP) principles. A PRICE Delphi Group (PDG) and PRICE Face‐to‐Face Meeting Group (PFMG) were then formed. The members of the PDG were invited to participate in an online Delphi process to achieve consensus on the wording and utility of the checklist items and the accompanying flow chart that was created to complement the PRICE 2020 guidelines. The revised PRICE checklist and flow chart developed by the online Delphi process was discussed by the PFMG at a meeting held during the 19th European Society of Endodontology (ESE) Biennial Congress in Vienna, Austria, in September 2019. Following the meeting, the steering committee created a final version of the guidelines, which were piloted by several authors during the writing of a case report. In order to help improve the clarity, completeness and quality of case reports in Endodontics, we encourage authors to use the PRICE 2020 guidelines.

Case reports play a key role in showcasing new, unusual or rare disease(s), and the impact of newer therapeutic approaches or interventions. The Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020 guidelines are being introduced exclusively for Endodontics by adapting and integrating the CAse REport (CARE) guidelines and Clinical and Laboratory Images in Publications principles. The PRICE 2020 guidelines have been developed to help authors improve the completeness, accuracy and transparency of case reports in Endodontics and thus enhance the standard of manuscripts submitted for publication. The aim of this document is to provide a comprehensive explanation for each item in the PRICE 2020 checklist along with examples from the literature that demonstrate compliance with these guidelines. This information will highlight the importance of each item and provide practical examples to help authors understand the necessity of providing comprehensive information when preparing case reports. A link to this PRICE 2020 explanation and elaboration document is available on the Preferred Reporting Items for study Designs in Endodontology website at http://www.pride-endodonticguidelines.org.

Despite enjoying high favourable outcome rates, root canal treatment is not always successful. Root canal retreatment is a widely practised option for managing a non‐healing root treated tooth. A basic distinction between retreatment and initial treatment is the requirement to remove the existing root filling material occupying the root canal space. Only then, can the technical deficiencies and possible causes of failure be addressed. Hence, the successful removal of the root filling material is critical to achieving the objectives of retreatment. Many different materials and techniques have been used for root canal filling, which have been documented in a plethora of studies; these are mainly laboratory studies investigating the removal of root filling materials. To help guide future research, which may then better inform clinical practice in relation to retreatment procedures, the focus of this narrative review is on the research methods and experimental models employed to study the removal of root filling materials. The current available literature demonstrates great variation in the research methodologies used to study the removal of root filling material, including direct visualization by splitting tooth samples or clearing, three‐dimensional radiographic imaging including using microcomputed tomography or cone‐beam computed tomography, and a combination of these techniques. Depending on the research method employed, variation also exists in quantification of root filling material removal; these include measurements of surface area, volume or weight, and criteria‐based (semi‐quantitative) assessment. Experimental models, using human teeth or resin models, differ with respect to standardization techniques and replication of the clinical scenario including initial sample preparation, canal filling, allocation and technical aspects of retreatment procedures. Future models should replicate, as closely as possible, the clinical scenario. Currently, microcomputed tomography provides a highly detailed, non‐invasive and non‐destructive method of objectively assessing and quantifying root filling removal.

Background: Development of a standardized set of topic‐specific outcomes known as a Core Outcome Set (COS) is important to address issues of heterogeneity in reporting research findings in order to streamline evidence synthesis and clinical decision making.Aim: The aim of the current international consensus study is to identify “what” outcomes to include in the Core Outcome Set for Endodontic Treatments (COSET). Outcomes of various endodontic treatments (non‐surgical root canal treatment, surgical endodontics, vital pulp treatment and revitalization procedures) performed on permanent teeth were considered.Methods: A standard validated methodology for COS development and reporting was adopted. The process involved identification of existing outcomes through four published scoping reviews. This enabled creation of a list of outcomes to be prioritized via semi‐structured patient interviews, e‐Delphi process and a consensus meeting with a range of relevant global stakeholders. Outcomes were prioritized using a 1–9 Likert scale, with outcomes rated 7–9 considered critical, 4–6 are important and 1–3 are less important. Outcomes rated 7–9 by ≥70% and 1–3 by <15% of participants were considered to achieve consensus for inclusion in the COS. The outcomes that did not achieve consensus in the first round were considered for further prioritization in the second Delphi round and consensus meeting. Final decisions about the outcomes to include in COSET were made by voting during the consensus panel meeting using the Zoom Poll function.Results: A total of 95 participants including patients contributed to the COS development process. The consensus panel recommended, with strong consensus, eight outcomes shared across all treatment modalities for inclusion in COSET: pain; signs of infection (swelling, sinus tract); further intervention/exacerbation; tenderness to percussion/palpation; radiographic evidence of disease progression/healing; function; tooth survival; and patient satisfaction. Additional treatment specific outcomes were also recommended.Discussion: Many of the outcomes included in COSET are patient reported. All should be included in future outcomes studies.Conclusion: COSET identified outcomes that are important for patients and clinicians and validated these using a rigorous methodology. Further work is ongoing to determine “how” and “when” these outcomes should be measured.