Cementum: A Strong Protective Layer for Teeth

Cementum: A Strong Protective Layer for Teeth

Cementum is a hard tissue layer that covers the root of the tooth, playing a vital role in protecting and anchoring the tooth in the socket. It differs from enamel in its yellowish-white color and lower hardness. Cementum has a complex structure, categorized into several types:

• Intermediate cementum: This is the first type of cementum to form, connecting to the enamel.

• Acellular, afibrillar cementum: This type of cementum lacks collagen fibers and cells.

• Acellular extrinsic fiber cementum: Found from the neck of the tooth to the middle of the root, it lies directly on the dentin.

• Cellular mixed fiber cementum: This cementum contains both collagen fibers and cells, interspersed with other types of cementum, often found around the apex, furcation, and the half of the root towards the apex.

• Cementoblasts: These are living cells that participate in the calcium phosphate exchange, contributing to cementum formation and resorption.

Relationship between enamel and cementum:

• Cementum can overlap enamel (60%).

• Cementum and enamel can meet (30%).

• Enamel can overlap cementum.

• Enamel and cementum may not be in contact.

Structure and composition:

• Cementum contains several organic components such as collagen and water, although the proportion is lower than in dentin and enamel.

• The inorganic components of cementum mainly consist of calcium and phosphate, with a lower proportion than enamel but higher than dentin.

Properties and function:

• Cementum has a yellowish-white color, easily distinguishable from enamel but difficult to distinguish from dentin.

• Cementum is less hard than dentin, comparable to bone.

• Cementum protects the root of the tooth, covers the dentin tubules, and helps anchor the tooth in the bone socket.

Cementum hyperplasia:

• Cementum hyperplasia is an abnormal thickening of cellular mixed fiber cementum (or acellular cementum).

• The cause of cementum hyperplasia can be tooth developmental disturbances, oral diseases such as impacted teeth, tooth displacement, chronic apical infection, or systemic diseases like bone formation disorders.

Cementum is an important part of the tooth structure, protecting and anchoring the tooth in the socket. Understanding the structure, function, and related diseases of cementum will help us take better care of our oral health.