incisors

Incisors are the front teeth of the human dentition. In both primary and permanent dentitions, each dental arch contains four incisors: two central incisors and two lateral incisors. Across the mouth, this yields eight incisors in the permanent dentition (four in the maxilla and four in the mandible) and eight in the deciduous dentition (four per arch).

Incisors have a single root and a broad, flat crown with a sharp incisal edge used for cutting food. Central incisors are typically larger and more robust than the lateral incisors, which are smaller and more slender. The enamel covers the crown, with dentin beneath, and the tooth contains a pulp chamber that extends toward the root.

The primary function of incisors is cutting and shearing food during mastication. They also contribute to articulation of speech and play a key role in facial aesthetics, providing lip support and serving as a midline reference for the bite.

Deciduous incisors erupt in infancy, usually from about six months (central incisors) to around 16 months (lateral incisors). Permanent incisors emerge later, with the lower central incisors typically the first to erupt around ages six to seven, followed by the upper centrals and laterals, and the remaining incisors through late childhood and adolescence.

Clinical notes: Incisors are common sites of dental trauma and wear. They can be affected by caries along the incisal edge, particularly with high-sugar diets, and may exhibit anomalies such as peg-shaped laterals or diastemas. Proper alignment of incisors is important for aesthetics, phonetics, and functional efficiency.