Oral Anatomy Lecture #3: Dentin, Enamel, and Cementum Characteristics

Main functions of Dentin

Covers the pulp, Makes the shape of the tooth

Hardness of Enamel

5 to 8 Moh (Diamond = 10 Moh), Harder than bone

Hardness of Dentin

Less hard than enamel, Harder than bone and cementum

Hardness of Cementum

Less hard and less calcified than dentin

Thickness of Enamel

Incisors’ incisal edges (2 to 3 mm), Cusps (3 to 4 mm)

Thickness of Cementum

The apical foramen and near the furcation of the root are the thickest parts of cementum

Specific gravity of Enamel

2.8

Weight of Cementum

Lighter than dentin

Color of Enamel

Varies according to thickness; Thin = Yellow

Color of Dentin (Permanent)

Yellow

Color of Dentin (Deciduous)

Light yellow

Color of Cementum

Light yellow

Translucency of Enamel

Semi

Transparency of Dentin

Semi transparent

Permeability of Enamel

Selective permeable due to enamel rods/prism, Inside rods are rod sheaths interconnected by interprismatic substances acting as glue

Permeability of Dentin

Permeable due to dentinal tubules

Permeability of Cementum

Permeable to various materials

Calcification of Cementum

A calcified structure, less hard, and less calcified than dentin

Consistency of Enamel (Permanent)

96% Inorganic, 4% Organic and water

Consistency of Enamel (Deciduous)

92 to 94% Inorganic, 6 to 8% Organic and water

Consistency of Dentin

65% Inorganic, 35% Organic

Consistency of Cementum

45 to 50% Inorganic (Hydroxyapatite), 50 to 55% Organic (Type 1 collagen, protein, and polysaccharides)

Elasticity of Dentin

Very high but less radio opaque than enamel due to less mineralization

Where does Cementum develop from?

Derives from a dental sac

Developmental origin of Cementum

Mesoderm (from the dental sac), which belongs to the 3 derm layers: Endoderm, Mesoderm, and Ectoderm