cyts and tumors:

The enamel organ is anepithelial structure that is derived fromoral ectoderm. The dental follicle and dental papilla are considered ectomesenchymal in nature because they are in partderived from neural crest cells

The enamel organ has four types ofepithelium... inner enamel epithelium.. stratum intermedium..stellate reticulum, followed by the outer enamel epithelium

Contact with the enamel organ epitheliuminduces the dental papilla to make odontoblasts that form dentin

Following the initial formation of thecrown, a thin layer of the enamel organepithelium known as Hertwig�s rootsheath proliferates apically to provide thestimulus for odontoblastic differentiationin the root portion of the developingtooth. This epithelial extension laterbecomes fragmented but leaves behindsmall nests of epithelial cells known asrests of Malassez in the periodontal ligament space.

However, if fluid accumulatesbetween the reduced enamel epitheliumand the crown of the tooth before tootheruption, a cyst is formed that is known asa dentigerous or follicular cyst

With rare exceptions, epithelium-linedcysts in bone are seen only in the jaws

developmental cysts are ofunknown origin; however, they do notseem to be the result of an inflammatoryreaction. Inflammatory cysts, on the otherhand, are the result of inflammation

Dentigerous Cystcommonly mandibular third molars.Other common associations are with maxillary third molars, maxillary canines, andmandibular second premolars.2They mayalso occur around supernumerary teethand in association with odontomas; however, they are only rarely associated withprimary teeth.2,in 10-30yrsm>fwhite>blackasyptomatic3 types:centrallateral

circumferentiald/d : dental follicle (h/p)

frozen-section analysis In thenoninflamed dentigerous cyst, a thin epithelial lining may be present with the fibrousconnective tissue wall loosely arranged (Figure 30-4). In the inflamed dentigerous cyst,the epithelium commonly demonstrateshyperplastic rete ridges, and the fibrous cystwall shows an inflammatory infiltrate

treated with enucleation ofthe cyst Large dentigerous cysts may be treatedwith marsupialization (Figure 30-6) whenenucleation and curettage might otherwiseresult in neurosensory dysfunction or predispose the patient to an increased chanceof pathologic fracture.

Support of this statementstems from the occasional formation of asquamous cell carcinoma, mucoepidermoid carcinoma, or ameloblastoma fromor in association with a dentigerous cyst

okc: