Thyroid & Adrenal
The following is associated with a nonerupted permanent tooth:
a. The second most common odontogenic cyst is the dentigerous cyst, which develops within the normal dental follicle that surrounds an unerupted tooth.
b. The dentigerous cyst is not thought to be neoplastic. It most frequently is found in areas where unerupted teeth are found: mandibular third molars, maxillary third molars, and maxillary canines, in decreasing order of frequency.
c. These cysts can grow very large and can move teeth, but, more commonly, they are relatively small.
d. Most dentigerous cysts are asymptomatic, and their discovery is usually an incidental finding on radiography.
e. The usual radiographic appearance is that of a well-demarcated radiolucent lesion attached at an acute angle to the cervical area of an unerupted tooth. The border of the lesion may be radiopaque. The radiographic differentiation between a dentigerous cyst and a normal dental follicle is based merely on size.
f. However, histologically, a distinction other than size is found. The dental follicle is normally lined by the reduced enamel epithelium , while the dentigerous cyst is lined with a stratified squamous nonkeratinizing epithelium. Dystrophic calcification and clusters of mucous cells may be found within the cysts.
g. Dentigerous cysts develop from follicular epithelium, and follicular epithelium has greater potential for growth, differentiation, and degeneration than the epithelium from which radicular cysts arise.
h. Occasionally, other more ominous lesions arise within the walls of the dentigerous cyst, including mucoepidermoid carcinoma arising from mucous cells within the cyst walls, ameloblastoma and squamous cell carcinoma.
i. These findings comprise most of the medical rationale for removal of impacted third molars with pericoronal radiolucencies; however, impacted teeth with small pericoronal radiolucencies (suggesting the presence of normal dental follicle rather than dentigerous cyst) may also be monitored with serial radiographic examination. .