PMC10030217_01
Case 1: (a) Preliminary photograph showed a defect of the palatal crown to the subgingival at tooth #25. (b) The original Cone-beam CT. (c) The apical radiograph revealed the insufficient distance between tooth #25 and the implant. (d) The coronal radiograph clearly showed that the apical lesion of tooth #25 destroyed the peri-implant bone (red arrow). (e) Three months after extraction. (f) Intraoral radiography one year after extraction (red arrow).
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Intraoral examination revealed that the palatal crown of tooth #25 fractured to the subgingival, resulting in exposure of the endodontic cavity (Figure 1(a)). Apical radiography of tooth #25 indicated that the distance between implant #26 and tooth #25 was insufficient, and inappropriate RCT of tooth #25 (Figure 1(c)). Cone-beam CT was used for a more comprehensive evaluation (Figure 1(b)); the apical infection in tooth #25 had spread to the implant tip; however, the patient claimed no clinical symptoms, even when tooth #25 and implant #26 were percussive. Radiographic follow-up of the patient at 3 and 12 months revealed resolution of the defect through increasing the density around the implant and within the extraction socket (Figures 1(e) and 1(f).
Histological evaluation of peri-implant tissue revealed infiltration of lymphocytes and plasma cells (x100).
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Moreover, a biopsy was performed; a large amount of plasma cell and lymphocyte infiltration was observed under the microscope, consistent with inflammatory granuloma (Figure 2).
PMC10030217_02
Case 2: (a) Preliminary Cone-beam CT before implant placement. (b) A coronal image of site #11 indicated the absence of labial bone and poor socket healing. (c) Fistulas were observed in the labial mucosa around implant #11(red arrow). (d, e) Follow-up visit after implant placement for 5 months, radiography appeared to indicate a mesial spread of apical periodontitis in tooth #12 to the coronal peri-implant defect (red arrow). (f) Apical radiograph revealed a diagnostic Gutta-percha cone tracing from mucosal fistulas to tooth #12 (red arrow). (g) Periapical radiographs at 1-month follow-up after filling the root canal with Vitapex. (h) Cone-beam CT indicated that RCT of tooth #12 was suitable, and the peri-implant bone defect was healed after half a year. (i) Intraoral photographs half a year after root canal filling. (j) The intraoral photograph of the implant-supported restoration 7 months after RCT showed healthy peri-implant mucosa. (k) Apical radiograph showed no defects of peri-implant supporting bone. Root canal therapy, RCT.
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A 24-year-old male serviceman was referred to an implantologist for the implant therapy of a traumatic maxillary incisor extraction (Figures 3(a) and 3(b)). Five months later, fistulas appeared in the facial mucosa at site #11 while preparing for the second stage procedure (Figure 3(c)). Radiography indicated a mesial spread of apical periodontitis in tooth #12 to the coronal peri-implant defect (Figures 3(d) and 3(e)). Diagnostic gutta-percha cone running along the fistulas indicated tooth #12 as the cause (Figure 3(f)). The mucosal healing around the implant and the periapical lesion of tooth #12 healed at the second visit, 4 weeks after the initial visit of RCT (Figure 3(g)). Follow-up after half a year with radiographs found healing evidence of the periapical radiolucency around the tooth apex #12 and the coronal part of the implant (Figures 3(h) and 3(i)). One month later, the implant was permanently restored with a cemented crown (Figures 3(j) and 3(k)).
The bacterial culture of peri-implant tissues showed Streptococcus as the main pathogenic bacteria. (Gram staining, x100).
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Streptococcus was observed under the microscope (Figure 4).