The presence of a new or persistent periapical radiolucency adjacent to a rootfilled tooth is often used as a criterion of endodontic treatment “failure”. However, clinicians’ suggested management of such cases is subject to substantial interindividual variation. Several components that might influence endodontic retreatment decision making have been explored, but data on which factors dentists actually think they consider, are missing. The aim was to interview 20 general dental practitioners (GPDs) and 20 endodontists about factors they thought would influence the prescription of endodontic retreatment. Six simu-lated cases were presented as cartoons accompanied with a clinical his-tory. In two of the cases the teeth were planned to serve as an abut-ment tooth in a fixed prosthodontic construction. The status of the periapical bone tissue and the quality of rootfilling seal were varied. Between 1 and 6 factors per case were reported to influence decision making. In cases not planned to serve as abutment teeth most dentists considered that the periapical condition was the most important fac-tor, whilst they considered the fixed prosthodontic construction to be the most important factor in cases planned as abutment teeth. Gener-ally, endodontists seem to be more inclined to retreat and act on the mere presence of a periapical lesion regardless of size than GDPs. In a real clinical setting in direct contact with patients, additional factors like economy and patients’ preferences might be expected to exert a major influence. The majority of the dentists stated that they thought that their colleagues would make similar decisions as they did them-selves.