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Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of the Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. ERM cells are unique epithelial cells that remain in periodontal tissues throughout adult life.

Origin. The junctional epithelium comes from the reduced enamel epithelium (REE) during the development of the tooth. This occurs before the tooth erupts and after the enamel matures. The ameloblasts produce a basal lamina on the surface of the tooth which serves as a part of the primary EA.

Stratified columnar epithelium - less common than the other stratified types. It has the secretion and protective functions of all columnar epithelia.

The entire surface of the oral mucosa is covered by squamous stratified epithelium. This is a highly organized, avascular, and semipermeable tissue whose thickness and degree of keratinization varies ing to the location in the oral cavity and the area's functional and mechanical requirements.

The junctional epithelium is a nonkeratinized stratified squamous epithelium which is derived from remnants of the reduced enamel epithelium during eruption of the tooth. Unlike other oral epithelia, it has only two layers (stratum basale and stratum suprabasale).

Each bundle of muscle fiber is called a fasciculus and is surrounded by a layer of connective tissue called the perimysium. Within the fasciculus, each individual muscle cell, called a muscle fiber, is surrounded by connective tissue called the endomysium.

The gingiva ends at the cervix of each tooth, surrounds it and attaches to it by a ring of specialised epithelial tissue — the junctional epithelium. This epithelial attachment provides continuity of the epithelial lining of the oral cavity with the surface of the teeth.

Teeth develop from the tooth germ, which is an aggregation of cells derived from the first branchial arch and the neural crest. The tooth germ is composed of the enamel organ, the dental papilla, and the dental follicle.