case_images: PMC11782284_01
case_images: Preoperative clinical intraoral photos and imaging results. (A) Labial view of tooth 22 showing an intact but discolored crown. (B) Palatal view of tooth 22 revealing a malformed lingual groove extending from the lingual fossa to below the gingiva. (C) Labial view of tooth 22 showing a residual sinus tract at the apical region. (D-F) CBCT results showing the malformed lingual groove on the palatal side extending to the apical area and connecting with a low-density image in the periapical region. The root canal is empty and exhibits a C-shaped configuration.
case_images: froh-05-1467327-g001.jpg
case_images: PMC11782284_01_froh-05-1467327-g001.jpg
case_images: F1
case_images: Cold stimulus testing showed no response, and electric pulp testing indicated a value of 80 compared to 8 for the control tooth (Figure 1A-C). The coronal view showed double root canals, and the horizontal view revealed a radiolucent C-shaped line extending from the pulp chamber to the periodontal ligament space (Figure 1D-F).
case_images: Intraoperative clinical intraoral photos and imaging results. (A) Immediate postoperative radiographic examination after root canal filling shows slight overfilling of the sealer. (B) Palatal view of tooth 22 after extraction, revealing the malformed central groove extending to the apical area, with overfilled sealer and black soft caries visible on the central root surface. (C) After preparation of the malformed central groove and root surface, the malformed groove and perforation area on the root surface are clearly visible. (D) The malformed groove is filled using a segmented approach. (E) Immediate postoperative radiographic examination after replantation. (F,G) Suturing and labial elastic fixation of tooth 22 following replantation.
case_images: froh-05-1467327-g002.jpg
case_images: PMC11782284_01_froh-05-1467327-g002.jpg
case_images: F2
case_images: The root canals were obturated using the warm vertical compaction technique with injectable root canal sealer (iROOT SP, Henry Schein), and the coronal cavity was sealed with a zinc oxide base and temporarily restored with glass ionomer cement (Figure 2A). The central palatal groove extended from the lingual tubercle to the apical foramen, revealing black soft caries and residual root canal sealer (Figure 2B). The groove and root surface were cleaned using a turbo diamond bur and ultrasound, and the apical 3 mm was removed (Figure 2C). The root part, including the root surface invagination, root surface defect, and apical retrofilling, was filled with a nano-bioactive material (iRoot BP Plus, Innovative Bioceramix Inc, Vancouver, Canada) to prevent reinfection (Figure 2D). The tooth was then replanted into the extraction socket and stabilized with an orthodontic stabilizing archwire (CO-AX 0.18) for labial elastic fixation (Figure 2E-G).
case_images: Postoperative intraoral photos and imaging results from regular follow-ups. (A) Radiographic examination results at 2 months postoperatively. (B) At 2 months postoperatively, the probing depth in the central palatal area of tooth 22 was reduced to 2 mm. (C,D) Tooth discoloration of tooth 22, shade matching, and post-internal bleaching show the crown color is consistent with adjacent teeth. (E,F) Radiographic examination and palatal probing depth check at 12 months postoperatively. (G,H) Radiographic examination and palatal probing depth check at 24 months postoperatively. (I-K) Radiographic examination and palatal probing depth check at 36 months postoperatively.
case_images: froh-05-1467327-g003.jpg
case_images: PMC11782284_01_froh-05-1467327-g003.jpg
case_images: F3
case_images: Radiographic examination showed the disappearance of low-density radiolucency at the apex and new bone formation (Figure 3A,B). Tooth #22 was recorded as shade 3M2 on the VITA shade guide, showing visible discoloration compared to the adjacent tooth #21, which matched shade 2M2 (Figure 3C). Products Inc., South Jordan, USA). Post-treatment, the color of the crown was harmonized with that of the adjacent teeth (Figure 3D). CBCT at the 3-year follow-up revealed dense root filling material with good sealing, gradual recovery of the periodontal membrane at the apex, and formation of new periodontal attachment without signs of ankylosis or external inflammatory root resorption (Figure 3E-K).