Cementum

A specialized calcified substance covering the root of a tooth. Its primary function is to provide a medium for the Periodontal Ligament (PDL) to attach the tooth to the alveolar bone.

Why It Matters

Cementum is much softer than enamel. If gum recession exposes the root, the cementum can be brushed away easily, exposing the sensitive dentin underneath. This is a common cause of sensitivity to cold water.

Clinical Details

• Composition: 45% inorganic (hydroxyapatite), 33% organic (collagen), 22% water.
• Types: Acellular (at the neck of the tooth) and Cellular (at the apex/tip).