Treatment of 2 impacted molars in a large dentigerous cyst (expansile cystic lesion) with combined orthodontic and surgical therapy

Nonmineralized cysts and cyst-like lesions that frequently occur in the mandible include ameloblastomas, odontogenic keratocysts, and dentigerous cysts. They have specific features of well-demarcated, unilocular, and radiolucent lesions that are often associated with tooth impaction. Although it rarely occurs, these cysts can become extremely large. Furthermore, cyst enlargement causes additional symptoms that can challenge the success of tooth recovery through orthodontic treatment. This clinical report presents the successful eruption of 2 impacted molars in a large dentigerous cyst treated with marsupialization and orthodontic traction using an orthodontic miniplate anchorage over a 4-year treatment period.

Graphical abstract

Highlights

  • Alternative camouflage treatment for impacted teeth is presented.

  • Marsupialization is a more conservative treatment modality in the dentigerous cyst.

  • C-tube plates provide effective anchorage for extrusion of the impacted mandibular molar.

Dentigerous cysts represent one of the typical pathologic diseases found in dentistry. Ishihara et al reported that dentigerous cysts account for approximately 24% of all true cysts in the jaw.

Cystic and cyst-like lesions of the mandible are well-defined corticated, unilocular, radiolucent, and demarcated of odontogenic or nonodontogenic origin. The dentigerous cyst is one of the most common types of noninflammatory odontogenic cysts, which causes a pericoronal area of lucency associated with an impacted tooth.

Dentigerous cysts are commonly treated by total enucleation or marsupialization. Marsupialization includes decompression of the cyst, followed by its removal with or without the extraction of an impacted tooth. Optimal treatment modality is selected by the size and site of the cyst, patient age, stage of the dentition, and involvement of vital structures.

The conventional orthodontic treatment modalities are mostly those using a fixed appliance without any skeletal anchorage devices for the traction of impacted teeth. , Although these conventional methods have produced acceptable results, they might have some complications such as unwanted tooth movement. To address this problem, orthodontists apply temporary skeletal anchorage devices (TSADs) to provide stable anchorage without any reciprocal tooth movement. Since TSADs were introduced to the orthodontic field, a single miniscrew has become the most widely used apparatus. However, this modality may not be appropriate for young adolescents because of the low bone density and high risk of damage to unerupted permanent teeth. In the case presented here, a titanium orthodontic miniplate was inserted in the opposing arch to serve as stable skeletal anchorage. This clinical report presents the recovery of impacted molars from a large dentigerous cyst treated with marsupialization and orthodontic traction using orthodontic miniplate.

Case report

A boy aged 10 years and 2 months, with a chief complaint of unerupted mandibular left molars, visited the clinic to receive treatment. On extraoral examination, slight facial swelling of the left posterior mandibular region was noted with no pain on palpation. An intraoral examination revealed that the overlying vestibular area around the lesion was intact, and there was fluctuation on palpation. Panoramic radiography and cone-beam computed tomography showed a well-defined unilocular and radiolucent lesion in the mandibular left body. A well-circumscribed radiolucency that looked like a cystic lesion started from the left second premolar and surrounded the crown of the molars. It showed severe displacement of the mandibular left first and second molars. The mandibular first molar was displaced bucco-inferiorly, and the mandibular second molar was in a distal position. Because of this lesion, the inferior border and buccolingual cortical plate of the mandible were thinned and expanded ( Figs 1 , A and B ). Based on the clinical and radiographic findings, the tentative diagnosis was a dentigerous cyst.

Fig 1
Pretreatment records: A, panoramic radiograph; B, cone-beam computed tomography axial image. X-ray images show a well-defined radiolucent cystic lesion on the mandibular left body area. This cystic lesion started from the second premolar and surrounded the crown of the molars. Because of this lesion, the inferior border and buccolingual cortical plate of the mandible were thinned and expanded.

Treatment

First phase: surgical intervention (marsupialization)

The primary objective of the treatment was to address the patient’s main concern of delayed eruption of the mandibular left molars. Thus, the treatment would involve extrusion of the impacted teeth into their normal positions in the dental arch and concomitantly reduce the bony defect. Additional objectives were to improve the occlusion, establish a Class I molar and canine relationship, and correct the dental midline deviation.

In collaboration with the Department of Oral and Maxillofacial Surgery, we attempted to tract the impacted teeth to normal position, followed by marsupialization of the cyst. After the formation of the mucoperiosteal flap, the upper part of the lesion was excised. During this process, we ordered a biopsy for histologic examination. The histopathologic examination results confirmed the lesion to be a dentigerous cyst. Regular follow-ups occurred after marsupialization with the expectation of spontaneous reduction of the bony defect and spontaneous eruption of the impacted teeth. Serial panoramic radiographs from pretreatment to 14 months after surgery showed gradual eruption of impacted teeth with bone formation ( Figs 2 , AF ).

Fig 2
Serial panoramic radiographs during first phase treatment: A, pretreatment; B, 2 months; C, 4 months; D, 7 months; E, 8 months; F, 14 months after surgery. As the cystic lesion was decompressed, the extent of the bone defect was reduced, new bone formation was observed from the peripheral region of the lesion, and the spontaneous eruption of impacted and displaced molars was promoted.

Second phase: orthodontic intervention

Diagnostic records were obtained 14 months after the first phase of treatment. Although some progress was accomplished without orthodontic intervention, the first molar was still impacted, and the second molar was in a distal position with mesially tilted angulation ( Figs 3 , AG ).

Jan 9, 2021 | Posted by in Orthodontics | Comments Off on Treatment of 2 impacted molars in a large dentigerous cyst (expansile cystic lesion) with combined orthodontic and surgical therapy
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