Application of Vacuum-Formed Cyst Plug-in Conservative Treatment of Jaw Cyst in Children

Abstract

Fenestration decompression, which can protect important anatomic structures and reduce surgical risk is the most preferred way for the treatment of jaw cysts in children, and wearing a cyst plug after the operation is the key to success. To enhance the retention of the cyst plug and promote the healing of the cyst, our team designed the vacuum-formed cyst plug to replace the classic one. This article presents a case of a jaw cyst in a 6-year-old girl who wore the vacuum-formed cyst plug after the fenestration decompression. Six months later, the cyst healed, and the permanent teeth affected by the cyst returned. This case showed that the vacuum-formed cyst plug offered a more comfortable experience and an explicit prognosis for children with jaw cysts, having high clinical application value.

A jaw cyst, one of the most frequently diagnosed lesions in the oral and maxillofacial region, is recognized as the most common osteodestructive and expansionary lesion affecting the jaw. Cysts in the jaws of children with mixed dentition often affect growing tooth germs and young permanent teeth, disturbing the growth and development of teeth, resulting in dentition defects and occlusal disorders.1 The classic treatment of jaw cysts is enucleation, which is the risk of destroying permanent tooth germs and damaging surrounding vital anatomic structures in children. In addition to functional and esthetic problems, the defects of the facial bone structure after destructive surgery may also engender psychological effects.2 Therefore, more scholars2–4 regard fenestration decompression as the preferred way for the treatment of jaw cysts in children.

After fenestration decompression, it is necessary to wear a cyst plug routinely to maintain drainage. The clasp and base of the traditional cyst plug play the main role of retention.5 However, because of the anatomic shape and arrangement of the teeth in the mixed dentition teenager, the retention force of the cyst plug is often insufficient, which may lead to accidental swallowing in children. Therefore, in this report, we designed the vacuum-formed cyst plug, whose retainer, the vacuum-formed part, covers the whole dentition and plays an important role in retention. The plug body is responsible for maintaining drainage, customized by the shape of the cyst, and reaches the bottom of the cyst cavity to facilitate the drainage of the cystic fluid.

CLINICAL REPORT

A 6-year-old girl was treated in the Department of Oral and Maxillofacial Surgery, Stomatological Hospital of Wuhan University. Clinical examination revealed that the region of the buccal gingiva of the left maxillary deciduous canine to the second deciduous molar was slightly swollen. The fluctuation was present on palpation while no tenderness or sign of local infection. Cone-beam computed tomography showed the crown of the first premolar, which has not yet erupted, moved to the root orientation, and the pericoronal dental follicle enlarged. A quasi-circular area of reduced bone density can be seen, with a clear boundary, involving the dental follicle of the second premolar, about 2×1.5×2 cm³ in size (Fig. 1).

FIGURE 1.

Initial imageology examination. (A) The initial panorama shows the pericoronal dental follicle of the left maxillary first premolar enlarged. (B) Initial CBCT shows a quasi-circular area of reduced bone density.

On the basis of the clinical examination and radiologic findings, the treatment process was as follows:

Stage One

Fenestration decompression and pathologic examination. The left maxillary primary molar was extracted under general anesthesia, and fenestration decompression was performed (Fig. 2A). Part of the cyst tissues was excised and sent for pathologic examination, which confirmed the diagnosis of odontogenic keratocystic tumor.

FIGURE 2.

Clinical photos. (A) Intraoral photo after fenestration decompression. (B) Initially plaster model. (C) Polished plaster model. (D) Vacuum-formed cyst plug. (E) Forming a drainage artery for the cyst plug by self-curing denture base resin. (F) Intraoral photo of wearing vacuum-formed cyst plug.

Stage Two

Model preparedness. On postoperative day 7, under the informed consent of the girl and her parents, the impression of the complete dentition and cyst cavity was made with silicone rubber (GC Corporation, Tokyo, Japan), and a plaster model was cast (Fig. 2B).

Stage Three

Making cyst plug. Fill the undercut so that the shape of the cystic wall of the model is a microfunnel, with a large mouth side and a small cyst side (Fig. 2C). One-millimeter-thick diaphragm (Yamahachi Dental, Japan) was selected, and shaped on the model under vacuum-formed pressure (Fig. 2D). The self-curing denture base resin was placed in the diaphragm of the cystic wall, and a channel about 2 mm in diameter from the oral side to the cyst side was formed in the resin, which was used as the drainage artery (Fig. 2E).

Stage Four

Wearing cyst plug and follow-up. Successfully tried on the vacuum-formed cyst plug-in, gave guidance to the girl and her parents about wearing, then with regular follow-up to adjust the drainage plug timely (Fig. 2F).

RESULT

Three months later, cone-beam computed tomography examination showed the hypodense bone area of the left maxillary dwindled (Fig. 3). The cyst plug was adjusted appropriately again and worn for another 3 months. Six months after surgery, the left maxillary first premolar came back to normal position, and the cyst cavity was basically vanished (Fig. 4).

FIGURE 3.

Postoperative imageology examination shows the hypodense bone area of the left maxillary dwindled after 3 months of fenestration decompression.

FIGURE 4.

(A) Postoperative panorama shows the left maxillary first premolar came back to normal position after 6 months of fenestration decompression. (B) Intraoral photo after 6 months of fenestration decompression.

DISCUSSION

At present, fenestration decompression has become a conventional method for the conservative treatment of jaw cysts.6 Many researches show that this method can eliminate the intracystic pressure leading to cyst expansion and destroy the hydrostatic pressure factor on which the cyst depends to enlarge.7 After fenestration, maintaining drainage fluently is the key to conservative treatment. Wearing a cyst plug is one of the routine ways.

The preliminary study5 of our group showed that the clasps and base commonly used to provide retention, support, and stability for cyst plug. However, for children at the mixed dentition stage, their teeth often lack undercuts due to factors such as anatomic shape or arrangement (permutation), which prevents the cyst plug from gaining sufficient retention. To solve this problem, we tried the vacuum-formed maintainer as the retainer for the cyst plug.

The vacuum-formed maintainer is a removable negative pressure-forming retainer that can cover the surface of all teeth in the dentition. It has become the first choice for orthodontists and patients after orthodontic treatment because of its beautiful appearance, low price, simple manufacture, and good wear resistance.8 Hazan-Molina et al9 described trimming the edge 2 to 3 mm below the free gingival line is beneficial to increase the retention force of the vacuum-formed retainer.

Breakage is the most frequently reported problem with vacuum-formed retainer, and most of the breakages were reported to occur in 6 to 9 months after vacuum-formed retainer wearing.10 Vacuum-formed cyst plugs need to be adjusted or replaced according to the recovery of the children’s jaw cyst or tooth eruption. In this case, we adjusted the cyst plug for the girl every month, and there was no damage discovered. Our group believes that because of the short replacement cycle of cyst plug, and the certain gap between the bite force of children and adults during chewing, the possibility of damage of the vacuum-formed cyst plug is relatively small.

Compared with traditional cyst plugs for the treatment of jaw cysts in children at the mixed dentition stage, vacuum-formed cyst plugs have certain advantages: first of all, the vacuum-formed retainer strengthens retention to prevent children from swallowing by mistake. Second, the vacuum-formed retainer fits better, and it is convenient to wear, which improves the children’s acceptance and compliance. In addition, the advantages of easy manufacture and low price make the vacuum-formed retainer shorten the production time of the cyst plug, and it is convenient for the doctors to adjust or remake it according to the intraoral condition of the children.

CONCLUSIONS

Fenestration decompression is the most preferred choice for the treatment of jaw cysts in children, and wearing a cyst plug after surgery is one of the keys to successful treatment. The vacuum-formed retainer cyst plug not only continues the advantages of the traditional cyst plug but also can increase the retention and stability while reducing the discomfort of initial wearing and shortening the adaptation time. In addition, because the vacuum-formed retainer has the advantages of durability, simple manufacture, and low cost, it is convenient for doctors to adjust or remake. Hence, the vacuum-formed retainer cyst plug combined with fenestration decompression is of great significance in the treatment of children with jaw cysts, which is worthy of further promotion.