40. What occurs during active eruption?
(The actual vertical movement of the tooth)
The Reduced enamel epithelium first fuses with the oral epithelium lining in the oral cavity. Second, enzymes from the REE disintegrate the central portion of the fused tissue, leaving an epithelial tunnel for the tooth to erupt through into the surrounding oral epithelium of the oral cavity. As the primary tooth actively erupts, the coronal portion of the fused epithelial tissues peels back off the crown, leaving the cervical portion still attached to the neck of the tooth. the fused tissue that remains near the CEJ after the tooth erupts then serves as the intial junctional epithelium of the tooth and creates a seal between the tissue and the tooth surface. the tissue is later replaced by a definitive junctional epithelium as the root is formed.41.Describe Reduced Enamel Epithelium(REE) and its role in tooth eruption.
Reduced Enamel Epithelium(REE) appears as a few layers of flattened cells overlying the new enamel surface. To allow for tooth eruption the REE has to first fuse with the oral epithelium and then the enzymes from the REE disintegrate the central portion of the fused tissue for the tooth to erupt.42.What is an odontoclast, and what is its role in tooth shedding?
Odontoclast absorb the aveolar bone between the two teeth. the odontoclasts role in tooth shedding is to cause resorption or removal of portions of the primary's root of dentin and cementum as well as small portions of the enamel crown.43.Meditate on the tooth fairy.
The tooth fairy is a mythological creature who at night takes children's shedded primary teeth from under their pillows and leaves a sum of cash.
44.Explain Nasymth's membrane.
residue from food debris that may form on newly erupted teeth of both dentitions and may leave the teeth extrinsically stained. It consists of the fused tissue of the REE and oral epithelium as well as the dental cuticle placed by the ameloblasts on the new enamel surface. it can be removed by gently selective polishing.