Management of a deeply impacted mandibular third molar and associated large dentigerous cyst to avoid nerve injury and improve periodontal healing: Case report

As dentigerous cysts increase in size, the risk of postsurgical complications increases as well. Emphasis is usually placed on the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the large residual bone defect. However, influence on the periodontal status of neighbouring teeth should also be taken into account. In this article, we present an interdisciplinary, safe, minimally invasive approach to treating large dentigerous cysts associated with deeply impacted third molars. A dentigerous cyst is an epithelial-lined pathologic cavity that develops in association with the crown of an unerupted tooth and appears radiographically as a well-circumscribed pericoronal radiolucency. 1 The cyst not only inhibits the eruption of the associated tooth (usually, a mandibular third molar),2 but can also carry it to unusual positions in the jaw.3-5 Dentigerous cysts may enlarge causing extensive bone resorption and even pathologic fracture.6 The greater the size of the cyst, the higher the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the postoperative bone defect.7,8 Moreover, the removal of large cysts can lead to a severe infrabony defect at the root surface of adjacent teeth, jeopardizing their long-term periodontal health. "Orthodontic extraction" is a combined orthodontic-surgical approach that decreases the risk of neurologic complications and facilitates the surgical extraction of impacted mandibular third molars that are in close contact with the mandibular canal,9-12 even when associated with cystic lesions.13 This case report shows that the interdisciplinary approach is also effective in preventing periodontal breakdown on the distal surface of the adjacent second molar.