A 14-year-old male patient (Table 1; patient 2) was seen for the first time for a routine dental examination. There was a history of dental trauma to the right maxillary central incisor (tooth 11; FDI), i.e. a crown fracture without pulp exposure at the age of nine and a restoration with a composite. A routine periapical radiograph revealed the presence of a periradicular lesion in association with teeth 11 and 12 (Fig. 1). Furthermore, apical root resorption was associated with teeth 11, 21 and 22 probably due to an earlier orthodontic treatment, though inflammatory resorption following trauma and pulp necrosis could not be ruled out. Out of all the four incisors, only tooth 11 did not respond to cold and heat, and showed a negative response to the electric pulp test. Tooth 11 was opened without anesthesia and root canal treatment was started. The root canal was dry and there was no apical exudation. After cleaning and shaping (MAF 80), Reogan-Rapid was injected into the root canal using the injection needle as provided by the manufacturer. During injection, the patient complained of pressure around the root apex. The control radiograph showed that the periapical lesion was filled with calcium hydroxide paste (Fig. 2). The next day the patient suffered from severe pain and a swelling of both buccal mucosa and upper lip. After 2 days, the pain as well as the extraoral swelling disappeared spontaneously. The intraoral swelling, however, remained. It was decided not to open the root canal and to postpone further treatment for 1 month. At the third appointment, it was not possible to completely dry the root canal and a new calcium hydroxide dressing was placed. Due to the open apex associated with the apical root resorption, an additional amount of calcium hydroxide was unintentionally added to the periapical mass (Fig. 3). This time there were no symptoms of pain and swelling.
The calcium hydroxide paste was refreshed after another month. The tooth remained asymptomatic, though the buccal mucosa was still sensitive to palpation. Care was taken not to introduce the new dressing into the periradicular region (Fig. 4). On the control radiograph (Fig. 4), it was seen that there was a white border surrounding the periapical lesion, with a diminished amount of periradicular calcium hydroxide. Finally, 3 months after initial consultation, the root canal was prepared to a MAF 90 and obturated by cold lateral condensation of guttaâ€“percha and AH 26 (Fig. 5). On the 1-year control radiograph, remnants of the calcium hydroxide dressing were visible in the periradicular region and the periapical lesion was notcompletely healed (Fig. 6).The 4-year control radiograph showed evidence of healing, though there was a white zone present embedded in the bone (Fig. 7).
Figure 1. Radiograph of the right central incisor with periapical radiolucency. Apical root resorption on both maxillary incisors is probably the result of orthodontic therapy.
Figure 2. Radiograph after placement of an intracanal calcium hydroxide dressing with unintentional periapical overextension.
Figure 3. Radiograph taken after renewal of the calcium hydroxide dressing 1 month after the start of endodontic therapy. An additional amount of calcium hydroxide was unintentionally added.
Figure 4. Radiograph taken after a second replacement of the calcium hydroxide paste, 2 months after the start of endodontic therapy.
Figure 5. Control radiograph of the root canal obturation, 3 months after initial consultation. The extraradicular calcium hydroxide had disappeared.
Figure 6. The 1-year control radiograph. There are still remnants of the calcium hydroxide paste. The size of the apical radiolucency is diminishing.
Figure 7. The 4-year control radiograph showing healing of the apical lesion and the presence of a white radiopaque spot at the place where calcium hydroxide remnants were originally present.