HISTOLOGY OF ENAMEL

Presented by: N. Robinson(CRRI)

INTRODUCTION Enamel is a higly mineralised structure

covering the anatomic crown of tooth. It is the only tissue that is totally acellular.PHYSICAL PROPERTIES: Colour:- appears bluish white or greyish at the

thick opaque areas & yellow-white at the thin areas reflecting underlying dentin.

ENAMEL

Hardness:- hardest structure of the body i.e.5 to 8khn.Permeability:- selectively permeable.Density:- decreases from the surface of enamel to the

dentino-enamel junction.Thickness:- thickness over the cusps of the molars where it

measures 2.5 mm & incisal edges of incisors where it is 2.0 mm.

CHEMICAL PROPERTIESEnamel is composed of organic & inorganic substancesOrganic --------> 4%Inorganic--------> 96%Water

1) Enamel rods(prisms)2) Rod shealths3) Cementing inter-rod substance.

STRUCTURE OF ENAMEL

Enamel Rod• Longitudinal section

Wavy course of enamel rod• Enamel rods followsa wavy course thefull thickness ofenamel• A more spiral courseis noted at cusps &incisal areas Gnarled enamel

• Enamel Rod: Basic Structural Unit

Cross section of enamel

Microscopic picture of EnamelBrown striae ofRetzius

DEJ, E tufts, E spindles

Enamel lamellae & Cracks

Perikymata (imbrication lines) Are external manifestations

of Retzius striae

Development of Tooth • Tooth and Associated Structures

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