A 13 year old male patient complains of pain in upper front teeth region and gives a history of fall on the ground while playing. Intra-oral examination reveals grade I mobility with maxillary left central incisor. Radiologic finding is suggestive of root fracture with 21. Which of the following could be the least favourable form of repair for this tooth?

Root fractures that occur in the apical half of the tooth are more likely to undergo repair. Fractures in the apical third are often repaired without treatment. In fact, many apparently are undetected until evidence of a calcified repair is seen radiographically sometime after the injury. Andreasen has described four tissue reactions after root fracture:  (1) Healing with calcified tissue, which is characterized by a uniting callus of hard tissue that may consist of dentin, osteodentin, or cementum. (2) Healing with interposition of connective tissue, in which the fractured root surfaces are covered by cementum with connective tissue fibers joining the two fragments. (3) Healing with interposition of bone and connective tissue, in which a bony bridge and connective tissue are positioned between the fragments. (4) Interposition of granulation tissue. The last is the least favorable form of attempted repair, and the fracture will not heal spontaneously.  The teeth usually present unfavorable symptoms that may be accompanied by fistulas resulting from necrosis of the coronal portion and also sometimes the apical portion of the pulp. These teeth require follow-up endodontic treatment or extraction.