Resorption and mineralization processes following root fracture of permanent incisors

Abstract The records of 85 patients treated for 95 root fractures of permanent incisors and followed regularly for up to 11 years were studied with respect to healing events after injury. The radiographic exposure best suited for disclosing root fractures in the apical third of the root was a steep occlusal exposure, while a conventional bisecting angle periapical exposure was optimal for revealing fractures in the cervical third. It is concluded that both exposures should, therefore, be used at the initial examination at the time of injury. Root resorption processes were observed in 60% of the material and could usually be detected within one year after injury. These preceded fracture healing and obliteration of the apical and/or coronal root canals. The changes observed represented one or more of four resorption entities: 1) external surface resorption, characterized by the rounding of the fracture edges mesially and/or distally; 2) internal surface resorption, manifested as rounding of the fracture edges centrally, in the apical and coronal root canals, at the intersection between the pulp canal and fracture line; 3) internal tunneling resorption, going behind the predentin layer and burrowing along the root canal walls of the coronal fragment; and 4) transient apical breakdown of the apical lamina dura. While the resorption processes were self‐limiting and required no treatment, the pattern of resorption and pulp canal obliteration appeared to be decisive for the type of fracture healing. Thus, all resorption entities collectively and internal tunneling resorption particularly were significantly related to healing at the fracture site by interposition of connective tissue. However, when seen alone, internal surface resorption was significantly related to fracture healing by hard tissue union. The different root resorption entities may represent osteoclastic activity connected with the ingrowth of new vascularized connective tissue into the fracture site or the coronal part of the root canal.