A Rare Case of Multiple Internal Root Resorption after the Delayed Treatment of a Traumatic Injury: A Case Report

Aim: The objective of this case report was to present a rare case of simultaneous multiple internal root resorption (IRR) in four mandibular incisors and discuss the possible etiology and suitable armamentarium for its treatment based on different morphological considerations. Background: IRR in permanent dentition is a rare pathological condition and its etiology is not yet fully understood. Very few cases of multiple IRR were reported. This is the first reported case of multiple IRR due to traumatic injury. Case description: A 23-year-old man suffered trauma to his mandible after falling from a trampoline. His mandibular incisors suffered subluxation injuries and his orthodontic fixed retainer got detached. He delayed treatment and visited our clinic 4.5 months after the incident. Clinical and radiographic examination revealed four mandibular incisors with almost identical IRR defects at the apical third of the roots. The patient was then treated with four non-surgical root canal treatments using various endodontic instruments and techniques. Fifteen-month post-trauma, he showed no evidence of pathology at the follow-up examination. Conclusion: Delayed treatment of dental trauma might cause multiple IRR, and the presence of an orthodontic fixed retainer can distribute surface forces and result in uniform IRR defects. Clinical significance: The combination of the self-adjusting file (SAF) and the XP-endo finisher is recommended for chemomechanical preparation of IRR defects in oval canals, especially at the apical third.