case_images: PMC7135686_01
case_images: Preoperative panoramic radiograph showing an ectopic eruption of the right maxillary third molar in a superior position near pterygomaxillary fissure inside the right maxillary sinus and surrounded by well-defined hyperdense lesion obliterating the right maxillary sinus cavity.
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case_images: A panoramic radiograph revealed ectopic eruption of the right maxillary third molar in the maxillary sinus with hyperdense lesion surrounding its crown and obliterating the sinus cavity ( Figure 1).
case_images: Multiplanar cone beam computed tomography (CBCT) sections: (
  a) three-dimensional; (
  b) sagittal; (
  c,
  d) axial; (
  e) coronal slices showing the posterosuperior position of the ectopic right third maxillary molar inside the maxillary sinus with associated pericoronal hyperdense lesion and radiographic evidence of oroantral communication due to its destructive effect on the maxillary sinus floor and the alveolar ridge.
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case_images: CBCT showed the ectopic third molar with incompletely formed roots located in the posterosuperior aspect of the right maxillary sinus with a close approximation to the orbital floor superiorly and pterygoid plates posteriorly ( Figure 2a). The CBCT also revealed the destructive effect of the associated pericoronal lesion on the right maxillary sinus floor and buccal cortical plate, distal to tooth #17, causing oroantral communication, which explains the reason for the purulent discharge, the chief complaint of the patient ( Figure 2b, 2c, 2d and 2e).
case_images: (
  a) Perioperative image showing the bony window created in the anterior wall of the sinus. (
  b) Underdeveloped ectopic molar with cystic lining.
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case_images: An oral and maxillofacial surgeon with 15 years of experience performed lateral sinus antrostomy, utilizing a standard Caldwell-Luc approach, with a bony window created in the anterolateral wall of the maxillary sinus ( Figure 3a). The cystic lining was identified, and the pus was drained prior to the complete removal of the cystic lining and extraction of the ectopic maxillary third molar ( Figure 3b).
case_images: (
  a,
  b) Photomicrograph of infected dentigerous cyst (x4, x10). (
  c) Photomicrograph of infected dentigerous cyst showing thin non-keratinized epithelium (x4).
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case_images: Part of the epithelial lining showed hyperplasia due to inflammation and long-standing lesion, and a connective tissue wall infiltrated with chronic inflammatory cells and composed of fibroblasts, collagen fibres and blood vessels, suggesting an infected dentigerous cyst ( Figure 4).
case_images: Multiplanar cone beam computed tomography (CBCT) slices: (
  a) axial cut showing bone formation medially; (
  b,
  c) sagittal and coronal cuts showing discontinuity of the antral floor and part of the anterior antral wall with oroantral communication starting distal to tooth #16.
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case_images: CBCT were performed three months after the surgery. CBCT axial cuts revealed some bone formation in the mediolateral dimension when compared to the preoperative radiographs, which indicates that the bone is in the healing process ( Figure 5a).