A calcified connective tissue that covers the root surface, covering the dentine.

- Dynamic: Provides attachment for the PDL - Smooth texture - Yellow in colour - Non vital - Less hard than enamel and dentine - Permeable to fluoride (Sensitivity) - Thin and easily removed at the CEJ which can cause dentine exposure and sensitivity - Root caries occurs easily on exposed cementum

50% inorganic: Calcium hydroxyapatite crystals 26% organic: Collagen fibres and ground substance 24% water by volume

Laid down in Incremental Lines of Salter 20-200 microns in thickness, thickest at apices

The relationship between enamel and cementum in the mouth can be described as 60% overlapping 30% meet 10% gap A gap between enamel and cementum can lead to exposed dentine, sensitivity and an increased perio risk

- First to be laid down - Covers entire root surface - No cells within the tissue - Cementoblasts on the surface

- Found at apices and furcations - Contains cementocytes trapped in lacunae -PDL provides nutrition ofr cementocytes

Granular Layer of Tomes

- Attachment of PDL - Protection of dentine tubules - Adaptable, allows functional movement

- Primary acellular cementum formation: Dental follicle cells become cementoclasts which lay down primary cementum - Secondary cellular cementum formation: Laid down by cementoblasts wnhich become embedded in lacunae as cementocytes