Autotransplantation of severely retained permanent canines: a retrospective clinical study on long-term treatment success and patient-related outcomes (PROMs) after a minimum 5-year follow-up

Introduction Canine autotransplantation (autoTX) functions as second-line therapy if orthodontic alignment is neither successful nor deemed feasible in severely displaced canines. The aim of this retrospective cohort study was to identify clinical and patient-related outcome factors influencing long-term treatment success after autoTX. Here, 'survival' refers to tooth retention regardless of complications, while 'success' requires absence of all defined failure criteria (ankylosis, pathological mobility, endodontic complications, radiological resorption, bone loss). In a previous retrospective cohort study with 378 canine autoTX in 319 patients a survival rate of 93.4% after a mean follow-up of 54.7 months has been reported. From this patient pool, a subgroup analysis was performed regarding autoTX success and patient-related outcomes after a minimum follow-up period of more than 5 years, thereby enabling analysis of long-term outcomes. Methods Patients with a minimum follow-up period of more than 5 years after autotransplantation were investigated for determination of autoTX success regarding clinical and radiological parameters. Additionally, patient related outcome measures (PROMs) were evaluated with a customized questionnaire. Results Clinical and radiological records of 42 patients with 53 grafts were available for analysis. Success rate was 41.5% after a mean follow-up of 75.7 months on tooth level. Canines with complete root formation were significantly more prone to endodontic treatment need, ankylosis, root resorption and pulp canal obliteration (PCO). Pre-operative orthodontic treatment showed a trend toward higher rates of PCO, but this difference was not statistically significant (p = 0.415), while post-operative orthodontic treatment was associated with a significant reduction in ankylosis risk (p < 0.02). Presence of dynamic or static occlusion to antagonists had a significant influence on the absence of endodontic treatment need, however not on the presence of ankylosis. Patient satisfaction was high, and all participants would choose autoTX as treatment option again. Conclusions AutoTX should be considered as a viable treatment option in cases of severe canine displacement, particularly in younger patients, with careful case selection and emphasis on post-operative orthodontic treatment.