Objective: The clinical outcome of endodontic therapy basically is assessed by radiographic analysis of the periapical tissues. An ideal concept of classifying the treatment result as a "success" or a "failure" was launched by Strindberg (SC). SC holds that a case with a persistent apical radiolucency, regardless of size, should be regarded as a "failure". Studies have challenged the acceptance of SC among general dental practitioners (GDP). As an alternative to SC the "Praxis Concept" theory (PC) was generated. PC hypothesises that dentists conceive periapical health and disease, not as an either/or situation but as different stages on a continuous scale. On the continuum a cut-off point is placed to separate the cases that should be retreated from those that should be not. Based on PC a technique was developed to assess and numerically express the inclination of a dentist to propose endodontic retreatment, the "Retreatment Preference Score" (RPS). In the present study the RPS technique was used to investigate endodontic retreatment concepts among 157 GDPs from Värmland, Sweden.
Methods: In six simulated cases the periapical condition, quality of root filling and presence or absence of a root canal retained post were systematically varied. Five options of management were offered: no therapy, wait-and-see, nonsurgical retreatment, surgical retreatment and extraction. For each examiner and case a RPS score was established.
Results: The investigation showed large interindividual variation in RPS scores. Choice of retreatment cut-off point was significantly influenced by the technical quality of root filling and presence or absence of crown and post. Only nine GDPs (6%) demonstrated retreatment decisions in accordance with the SC concept.
Conclusion: Data from the present study indicate that the suggested Praxis concept may be valid among a large majority of Swedish GDPs.
