A mineralised connective tissue

- Makes up the bulk of the tooth - Structural support for enamel - Protects the pulp - Vital: Responsive to stimuli - 30'000-70'000 tubules per mm squared

70% inorganic: Calcium Hydroxyapatite 20% organic: collagen fibres and ground substance 10% water

- Tubular - Tubules run parallel to each other - Extend from the pulp to the ADJ and the root cementum - Tightly packed in a 's' shaped from pulp to ADJ

Dentine formation

- Formed by odontoblasts - Begins during the 'Bell Stage' of development - odontoblasts move inwards towards pulp - Each odontome elongates forming an odontoblastic process (Tomes Fibre), which secretes pre dentine - The pre dentine begins to calcify forming a tubule which fills with dentinal fluid

1) Primary dentine: Laid down as tooth is developing 2) Mantle dentine: First layer of dentin, upper layer next to the enamel 3) Intertubular dentine: Between tubules 4) Peritubular dentine: Lines the tubules 5) Interglobular dentine: uncalcified dentine in matrix 6) Secondary dentine: Laid down once root formation is complete and continues throughout life

1) Hyaline layer: A layer of ground substance adjacent to the CEJ 2) Granular Layer of Tomes: Between dentine and cementum in the root 3) Contour lines of von ebner: minor growth lines at regular intervals 4) Contour lines of owen: major growth lines at irregular intervals, usually caused by illness 5) Neonatal lines

1) Tertiary dentine: Laid down as a response to stimuli directly below the affected area 2) Translucent dentine: Found in the root, a calcification of dentine tubules 3) Dead tracts: Empty tubules 4) Tetracycline staining: Creating banding of stain 5) Dentinogenesis imperfecta: Poor formation of dentine, teeth appear blue/grey

Dentine and pulp are considered to be a complex - odontoblasts come to rest in the pulp tissue - pulp provides vitality for odontoblasts - pulp is nutritive and sensory to dentine - secondary dentine is laid down in response to stimuli from the pulp