case_images: PMC7790565_01
case_images: Preoperative photograph and radiographs. Intraoral photographs of the right central and lateral incisor with swelling and spontaneous pain (a). The periodontal pockets were around 1-2 mm circumferentially, and there was no bleeding on probing sites. Intraoral radiographs showed no carious lesions in either incisor, but radiolucent regions were seen around the apexes of the maxillary right central and lateral incisors (b). Both incisors showed normal responses to the dental pulp cold stimulus test. Panoramic radiographs showed numerous apical and carious lesions in the mouth (c). The closest lesion to the site was the maxillary right first premolar. Intraoral periapical radiographs showed apical lesions of the maxillary right first premolar (d).
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case_images: PMC7790565_01_CRID2020-8830524.001.jpg
case_images: fig1
case_images: Mucosal swelling and spontaneous pain were seen at the labial gingiva of the maxillary right lateral incisor, and tooth mobility started at three months before the initial examination (Figure 1(a)). Intraoral periapical radiographs showed radiolucency at the apical regions of the central and lateral incisors, although no dental caries were detected in these incisors (Figure 1(b)). Panoramic radiography showed numerous dental caries and apical lesions in the oral cavity (Figure 1(c)). Intraoral periapical radiography revealed an apical lesion in the maxillary right first premolar (Figure 1(d)).
case_images: Preoperative CBCT images. Hypodense regions were seen around the apexes of the central and lateral incisors (a, b). Marked apical bone resorption around the lateral incisor (a, c). The palatal root canal of the first premolar was untreated and an apical lesion was observed (d). The apical lesion of the maxillary right first premolar had extensively spread in the anterior direction from the palatal side, destroyed the bone by circumventing the palatal side of the adjacent canine, and reached the apical areas of central and lateral incisors (e).
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case_images: PMC7790565_01_CRID2020-8830524.002.jpg
case_images: fig2
case_images: We also found apical radiolucency with destruction of the cortical bone on the buccal side, measuring >=12 mm in diameter on the lateral incisor, and an apical radiolucency measuring >=8 mm in diameter on the central incisor (Figures 2(a)-2(c)). Root canal filling material was found on the buccal root of the maxillary right first premolar, and no root canal filling agents were seen in the palatal root, with an apical lesion measuring more than 10 mm in diameter on the palatal side (Figure 2(d)). Furthermore, the apical lesion had spread extensively from the palatal apical lesion and reached the apical areas of the central and lateral incisors that were the sites of the chief complaint (Figure 2(e)).
case_images: Postoperative intraoral radiographs and photograph. Intraoral radiograph of the maxillary first premolar just after root canal filling (a). Intraoral periapical radiograph of the maxillary right central and lateral incisors after 6-month period from the retreatment of only the first premolar; the radiolucent regions tended to heal (c). Intraoral periapical radiograph of the maxillary first premolar and incisors after a three-year period: the radiolucent region of the premolar was healing. The retreatment of the root canal of the second premolar and first and second molars were realized (b), and the radiolucent regions of incisors had almost disappeared (d). Intraoral photograph of right central and lateral incisor after three years (e).
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case_images: PMC7790565_01_CRID2020-8830524.003.jpg
case_images: fig3
case_images: Abutment was prepared using a flowable resin composite, and a temporary crown was placed (Figure 3(a)). This treatment led to the disappearance of swelling at the maxillary right central and lateral incisors approximately two weeks postoperatively, and intraoral periapical radiographs showed a tendency of disappearance of the apical radiolucency approximately six months postoperatively (Figure 3(c)). After three years, intraoral periapical radiographs and CBCT images showed that apical radiolucency almost disappeared around the maxillary first premolar and incisors (Figures 3(b), 3(d), 4(a), 4(b), and 4(c)). The mobility of the central and lateral incisors improved to grade 0, and the dental pulp was preserved, leaving vital teeth with no symptoms (Figure 3(e)). CBCT shows bone destruction around the lateral incisor, also visible on the periapical radiography, and there is also a hypodense image between the roots of the premolar (Figure 3(d), 4(a), and 4(e)), requiring a longer follow-up.
case_images: Postoperative CBCT images. CBCT images of the maxillary right central and lateral incisors after a three-year period from the retreatment of only the first premolar; the hypodense regions had almost disappeared (a-c). Volume rendering image after three years showed that the buccal cortical bone had clearly recovered (d). Axial image of maxillary front to premolar area after three years shows the progress of osteoanagenesis in the palatal area (e).
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case_images: PMC7790565_01_CRID2020-8830524.004.jpg
case_images: fig4
case_images: After three years, intraoral periapical radiographs and CBCT images showed that apical radiolucency almost disappeared around the maxillary first premolar and incisors (Figures 3(b), 3(d), 4(a), 4(b), and 4(c)). CBCT shows bone destruction around the lateral incisor, also visible on the periapical radiography, and there is also a hypodense image between the roots of the premolar (Figure 3(d), 4(a), and 4(e)), requiring a longer follow-up.