Root Fracture of an Immature Permanent Tooth with Open Apex: A Case Report

DISCUSSION

Numerous forms of injury can occur as a result of dental trauma. The prognosis of these injuries varies. In general, many factors play an important role in influencing the outcome and pattern of repair (Saad, 1991; Andreasen and Hansen, 1967; Brambilla and Cavalle, 2007). Apart from the crown fractures, root fractures involve cementum, dentin and pulp tissue. Successful union of root fragments is aided by vital pulp tissue and a healthy periodontium. With most root fracture maintaining vitality of the pulp, the main goal of treatment is to enhance this healing process. The clinician should try to reunite the fractured segments by calcific callus formation because the tooth will be stronger than one without the union of broken parts.

Extraction may not be the only alternative for the root fractures. Even for fractures under the alveolar margin, alternative multidisciplinary approaches can be used to restore and allow the tooth to survive (Demiralp et al., 2007).

The prognosis of root fractures depends on the extent of the fracture line, the pulp tissue situation, occlusion, dislocation of fragments and the general health of the patient. From the scientific literatures, the sequelae to root fractures may be divided into four categories: i)healing with cementogenic or calcified tissue, ii) healing with interproximal dense connective tissue, iii) healing with interproximal bone and connective tissue, iv) interproximal inflammatory tissue without healing (Andreasen et al., 1989; Andreasen and Hansen, 1967; Mata et al., 1985; Michanowicz et al., 1971; Kothari et al., 1994).

The healing of horizontal root fractures seems to involve hard tissue deposition in and around the fracture site and calcification in the pulp spaces both in the apical and the coronal segments. Repair appears to depend on an intact periodontal ligament, from which the hard tissue forming cells originate (Andreasen and Hansen, 1967; Herwejier et al., 1992). If the fragments are more separated, the fracture spaces fill with cellular mineralized hard tissue or bone surrounded by connective tissue [Type-3] (Herwejier et al., 1992). Contrary, if the fragments are narrower, the fracture line can be healed with cementogenic and/or calcific tissue as seen in our case [Type-1 or 2].

Despite keeping of vitality in both coronal and apical fragments is essential; of the cases with horizontal root fractures, 43.7% have had pulp necrosis (Al-Nazhan et al., 1995). When the coronal pulp becomes necrotic and there is no radiographic or clinical evidence that the apical segment is irreversibly inflamed or necrotic, the treatment of the coronal segment only is indicated. The apical segment will probably remain vital. Therefore, in most cases of unhealing root fractures only the coronal segment is treated (Hovland, 1992).

In initial treatment, an apexification procedure of the segment should be performed before obturation of the root canal (Çaliskan and Turkun, 1996). This technique involves the repeated placement of calcium hydroxide over a period of 6-24 months until a calcific barrier is formed at the fracture line (Cvek, 1974). The use of calcium hydroxide in teeth with horizontal root fractures was first recommended by Cvek (1974). He proposed that the canal at the level of the fracture line is comparable to the apical foramen of an immature tooth. Thus, he assumed that the repair would be similar to the apexification procedure employed for the tooth with an open apex (Mata et al., 1985). Similarly, in a study by Jin et al. (1996) an experimental-root-fracture-model in dog teeth revealed that the early reaction of the wound healing was infiltration of inflammatory cells particularly at the coronal part of the fracture, whereas less inflammation but more abundant collagen fibers were seen at the apical part of the fracture (15 and 30 days). At day 180 (6th month) bone tissue healing was observed. Same authors also suggested that in the fractured-root, the regeneration of blood vessels is important in the wound-healing process and the revascularization is synchronized with the fracture wound healing. In parallel with these evidence and suggestions, in our case, a conspicuous hard tissue formation has been observed between the coronal and apical segments following the repeated placement of calcium hydroxide during 2 to 8 months period. When compared to similar cases presented in literature, the time needing to close fracture-line is considerably short. Probably, the vitality of apical segment can facilitate the hard tissue deposition at the fracture-line. Moreover, proximity of fragmants can also responsible for this fast-healing.

The relationship between healing complications and preinjury and injury factors could generally be explained by better healing possibilities in teeth with immature root formation. A possible explanation for that could be the softer bone surrounding the tooth, whereby trauma to the periodontium might be diminished (Andreasen et al., 2006).

Interestingly, apart from the root-fractures reported just now, our case represents an open apex to be close to eliminating the risk of apical pathosis in the following years. Of course, keeping the vitality of apical root segment has led to natural closure of apical-foremen, indicating the continuing cementoblastic activity.

In the case presented here, it was clearly understand from the case presented here that not only a proper endodontic and/or conservative treatment, but also adequate observation period were necessary to diagnose pathological changes to be occurred following years. After an adequate observation period, if vitality and/or radiographic control reveals non-vital pulp tissue, or if the patient complains of pain or discomfort of the tooth, then endodontic therapy can be performed along the all root-length.