This is a case report of a 43-y.o. female patient who suffered a home accident, which resulted in the incomplete alveolar fracture of regio 23-25, labial luxation and displacement of 23. Primary trauma care missed the dental diagnosis and delayed with 48 hrs the report of the patient to the dentist, that referred her immediately to the endodontist. On examination, 23 labially out of alignment and severe pain at slightest touch were noticed. Standardized radiographs revealed a very thin, artifact-like horizontal fracture of the mid third root of 23. Many treatment options, varying from avulsion to transfixation of 23 were taken into consideration. As the endodontist' suggestion was the extreme conservative treatment attempt, the incomplete alveolar fracture was reduced under anesthesia, the root canal treatment with Ni-Ti rotary instruments (ProTaper - Dentsply-Maillefer) was performed and Root-MTA was placed into the canal as permanent dressing. 23 was splinted in correct position. There was no post-treatment simptomatology. At 4 months, the tooth remains asymptomatic with no mobility. Radiographic examination reveals a blurry profile of the fracture site, with very slight periradicular modifications. The case report suggests that 1) deep horizontal root fracture combined with teeth displacement can be successfully treated 2) the immediate intervention of the practitioner with the rationale application of the sequence replacement-rotary root canal treatment-Root-MTA-splinting spectacularly improves the conservative outcome of similar cases. Schlagwörter: root fracture, displacement, RootMTA