Dentigerous cyst containing multiple impacted teeth: A rare case report

The Abstract:

Dentigerous cyst is a developmental odontogenic cyst, which apparently develops by accumulation of fluid between reduced enamel epithelium and the tooth crown of an unerupted tooth. It is one of the most prevalent types of odontogenic cysts associated with erupted, developing or impacted tooth, particularly the mandibular third molars, the other teeth that are commonly affected are maxillary canines. The present case report is unique as it enclosed the three permanent maxillary teeth: the central incisor ,lateral incisor and canine which had to be extracted during surgical enucleation of the cyst.

INTRODUCTION:

A cyst is defined as a pathological cavity lined by epithelium. The epithelium itself is surrounded by fibrocollagenous connective tissue and may be derived from various sources. Odontogenic cysts are derived from odontogenic epithelium which is derived from the basal epithelium of the stomodeum.[1]
A Dentigerous cyst is an epithelium-lined developmental cavity that encloses the crown of an unerupted tooth at the cemento-enamel junction. Dentigerous cysts are the second most common odontogenic cysts after radicular cysts, accounting for approximately24% of all true cysts in the jaws. Their frequency in the general population has been estimated at 1.44 cyst for every 100 unerupted tooth, and although it may involve any tooth, the mandibular third molars are the most commonly affected.[2]

CASE-REPORT:

A 10 year 3 month old male reported to the department of Pedodontics, Government dental college, Rohtak with the complaint of decayed teeth and demanded restoration of the same. Past history revealed that the patient had never been to dentist earlier for his dental treatment. Clinically, the patient had no apparent swelling, no discomfort, tenderness and other clinically relevant finding. There were no associated syndromes or systemic diseases present. During intraoral examination of the child it was found that the child had retained primary maxillary left central incisor, lateral incisor and the canine[Figure 1].Diagnostic intraoral periapical and maxillary occlusal radiograph showed a radiolucent lesion measuring approximately 3x3.5 cm in the alveolar process of maxilla on the left side encircling the three impacted permanent teeth- central incisor, lateral incisor and canine[Figure 2&3].The contents of radiolucent lesion were aspirated and sent for investigation, the result of which was consistent with the diagnosis of cystic lesion.
After clinical and radiological examination, a provisional diagnosis of dentigerous cyst was made. Routine blood and urine examinations were advised, the results of which were within normal limits. Surgical enucleation of the cyst and bracket placement on the three permanent anteriors to facilitate orthodontic extrusion was chosen as the treatment of choice. The surgery was done using using local anaesthesia and under antibiotic cover. After raising the flap, it was found that the three anteriors were one behind the other and in a criss-cross position[Figure4].With orthodontic consultation it was found that it was not possible to extrude the teeth and also to completely enucleate the cyst with the teeth in such a position. Hence, it was decided to sacrifice the teeth and the cyst lining was completely removed and was sent for histopathological examination[Figure 5].The histopathological examination showed a thin fibrous cystic wall lined by 2-3 layer thick non-keratinized stratified squamous epithelium with islands of odontogenic epithelium. The connective tissue showed a slight inflammatory cell infiltrate, which confirmed the diagnosis of dentigerous cyst
[Figure 6].Healing was uneventful and one week after the surgery, the surgical site showed good healing and the sutures were removed. Oral rehabilitation consisted of a removable partial denture which was delivered after the bone remodeling was complete [Figure 7].
DISCUSSION:

Dentigerous cysts are the most common of the developmental odontogenic cysts of the jaws and account for approximately 20-24% of all the epithelium lined jaw cysts.[3] Bilateral dentigerous cysts have been reported in the literature and usually occur in association with syndromes like mucopolysaccharidosis and cleidocranial dysplasia.[4] Dentigerous cyst is always associated with the crown of an impacted, embedded or otherwise unerupted tooth. Dentigerous cysts are typically asymptomatic and may be large, destructive, expansile lesions of the bone.The highest incidence of dentigerous cysts occurs during the second and third decades.Radiographic appearance is that of a well-defined radiolucent lesion ,which may be unilocular or multilocular in appearance. In addition to its potential for bone destruction and because of the multipotential nature of this epithelium derived from the dental lamina, several entities may arise in or be associated with the wall of a dentigerous cyst. [5]
As dentigerous cysts are frequently associated with impacted teeth, it occurring in association with canines is frequent as the canines are the commonly impacted anterior teeth .Maxillary canines are the most commonly impacted teeth, second only to third molars.[6,7]Maxillary canine impaction occurs in approximately 2% of the population and is twice as common in females as it is in males.[8,9] The surgical techniques used to treat and manage impacted maxillary canines are: Cantilever system, Temporary anchorage devices, Double archwire mechanics, Easy-way-coil system, Auxillary arm from transpalatal arch, Auxillary spring,K-9 spring. [10]
Radiologically well defined radiolucent lesions with sharp margins occurring in the maxilla and mandible may be odontogenic or nonodontogenic in origin: such as radicular cysts, odontogenic cysts, odontogenic keratocyst, non-odontogenic cysts like simple bone cysts,aneurysmal bone cyst, staffne cyst or even tumours such as ameloblastoma. Thus, it is essential to differentiate these lesions from dentigerous cyst on basis of clinical ,radiographic, and histopathological features. The differentiating features are as under:
Radicular cyst is the most common odontogenic cyst of the maxilla and the mandible. Radiologically it arises from the apex of the root of a carious tooth and is bounded by a thin rim of cortical bone.The differentiating feature of this entity is its relation to the root of a carious tooth. [11]
According to Tsukamoto et al [12], the mean age of patients with odontogenic keratocyst is less than that of patients with dentigerous cyst; the mean area of the odontogenic keratocyst is larger than that of dentigerous cyst and the dentigerous cysts are more likely to have smooth periphery and odontogenic keratocysts are more likely to have scalloped periphery. It is not possible to differentiate unicystic ameloblastomas from dentigerous cyst with clinical and radiographic examination. [13]
Nonodontogenic cysts are observed in the region of incisive canal or nasolabial region. The incisive canal cyst is in the midline located between the roots of the central incisors of the maxilla and is characteristically heart shaped. The nasolabial cyst occurs in the soft tissues of the lateral aspect of the nose and upper lip. These cysts are therefore diagnosed by their characteristic anatomical location. Aneurysmal bone cyst is seen as expansile multilocular radiolucent lesion. CT/MRI may reveal presence of blood or fluid contents in the cyst. [11]
It is important to perform radiological examination in cases of unerupted teeth. Initially a panoramic radiograph may be used for this examination. However, in cases of extensive lesion, CT scan becomes necessary.[2,14] Radiographic examinations provide valuable information. However, in cases of associated lesion pathological analysis of the lesion is essential for definitive diagnosis. [15]

REFERENCES:
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LEGENDS FOR FIGURES
Fig.1-Intraoral view of the patient revealing retained maxillary left central incisor, lateral incisor,and canine	Fig.2-Intraoral periapical radiograph of the anterior maxillary region

Fig.3-Maxillary occlusal radiograph showing radiolucent lesion surrounding three impacted permanent teeth	Fig.4-Flap raised and bone cutting done to expose the impacted teeth

Fig.5-The three impacted teeth after extraction	Fig.6-Histopathological picture of the lesion

Fig.7-Postoperative view after rehabilitation