ODONTOGENIC CYSTS
Odontogenic cysts are non malignant lesions characterized by endosseous development with continuous and progressive growth that deforms the bone. This type of cysts can be defined as an epithelium-lined pathological space. Cysts vary in histogenesis, frequency, behaviour and treatment.
- Radicular cysts: are by far the most common cysts of the jaws. These inflammatory cysts derive their epithelial linings from proliferation of small odontogenic epithelial residues (remnants of Malassez) within the periodontal ligament. They develop from a preexisting periapical granuloma that is initiated and maintained by the degradation products of necrotic pulp.
- Follicular cysts: is the second most common odontogenic cyst associated with an unerupted or developing tooth.
- Germinal cysts: these cysts arise from incompletely developed dental germ or a dental element.
CLINICAL FEATURES
Most cysts are localized in the maxilla, particulary in the anterior region, followed by the maxillary posterior region, the mandibular posterior and then the anterior region. Most cysts are asymptomatic and are often dicovered occasionally during routine dental radiographic examination. A swelling may be present when the cyst cause bone reabsorption and thinning of the cortical.
The mucosal aspect is normal and there are no inflammatory symptoms. Diagnosis is made by x-ray that may show an area of radiolucency associated with a dental element. A CT scan can also be performed.
The therapy is the surgical removal of the associated tooth and the enucleation of the soft tissue components. Some authors describe the marsupialization of the cyst in order to obtain a volume reduction before surgery. Possible transformation of cysts to ameloblastoma may occur expecially dentigerous cyst.
Carcinomatous transformation of the lining is rare. In cases in which mucous cells are present potential is believed to exist for the development of the rarely seen intraosseous mucoepidermoid carcinoma.
NON ODONTOGENIC CYSTS
- Globulomaxillary cysts: arise from odontogenic epithelium located between the maxillary lateral incisor and the canine.
- Nasolabial cysts: soft tissue cysts of the upper lip. The pathogenesis is unclear but it was considered to arise from epithelial entrapment at the fusion site of the soft tissue components of the globular and maxillary process. The clinical sign is a soft tissue swelling over the canine region or the mucobuccal fold. If untreated, the cyst continues to grow slowly and may ultimately deform the alar nose.
- Median mandibular cysts: can be considered as globulomaxillary cysts. They are present in midline of the mandible and does not preclude an odontogenic origin.
- Nasoplatine canal cysts: located within the nasopalatine canal. In all probability represent odontogenic cysts, possibly a primordial cysts of supernumerary (mesiodens) tooth.
- Traumatic bone cysts: is probably associated with a traumatic event. It has been suggested that a traumatical induced haematoma within the intramedullary portion of bone. Rather than organizing, the clots break down, leaving an empty bony cavity.
- Epidermoid cysts: mostly localized in the mandible near the angle and arising from ectodermic inclusions during the embryonal stage.