Definition of Primordial Cyst:
A Odontogenic cyst developing from the stellate reticulum which is formed in place of a tooth.
- Develops through liquefaction and cystic degeneration of stellate reticulum of enamel organ before any calcified enamel or dentine is formed.
- Usually it may develop from a normal tooth germ, which may be clinically missing from the arch or a supernumerary tooth germ or from dental lamina
- Accounts to 5-10 % of the Jaw Cysts
- It is seen in place of a tooth in an Edentulous area
- Location: Mandibular third molar region, Ramus region, Pre molar region, incisor region
- May occur early in life but usually discovered later
- Usually a tooth is missing
- Varies in size
- May expand bone and displace teeth
- Well demarcated , round or oval radiolucency with sclerotic or reactive border
- Unilocular or multilocular
- Seen below or between roots or near to the alveolar ridge
- More in relation to third molars
Based on Histology it is of 2 types:
- Keratinized type (more common)
- Non-Keratinized type (less common)
- Connective tissue capsule shows parallel arrangement of collagen bundles, with varying compactness.
- Epithelial lining is of stratified squamous – intact or interrupted.
- Epithelium may also be sometimes non keratinized, with a prominent spinous layer and long and confluent rete ridges and with less conspicuous basal layer.
- Sometimes the epithelium may be ortho keratinized with a thin to moderate spinous layer and a thin or flattened basal layer.
- Sometimes the epithelium may also be para keratinized and corrugated in some areas or may also be uniform 6 – 10 cells thick, with a prominent basal layer – with the cells arranged in a PICKET FENCE pattern or TOMB STONE pattern
- Rete ridge formation is not seen (cf. : odontgenic kerato cyst)
- Inflammatory infiltrate may be variable.
Radical surgery – Curretage of Bone
Recurrence: Highly recurrent.