Dental Anatomy

Teeth are fundamental to the digestive process and form part of the facial structure. A basic knowledge of dental anatomy can help you identify abnormalities and understand corrective or restorative procedures.

Tooth Identification.

The jaws are divided into 4 quadrants to help identify the teeth.

There are 32 teeth in the adult mouth. They are commonly numbered starting from the last molar of the upper right quadrant and ending at the last molar of the lower right quadrant.

Types of teeth.

Teeth are categorized based on their structure and function as:

Incisors: These are the front teeth of the upper and lower jaws. There are 2 in each quadrant close to the midline. Incisors have narrow, flat upper borders that help them cut through food.

Canines: Canines are single pointed teeth. There is 1 canine present in each quadrant at the side of the incisors. Canines help hold and tear food.

Premolars: Premolars have 2 projections on their upper surface. There are 2 premolars present in each quadrant just after the canines.

Molars: These teeth have a flat upper surface with 3 to 4 projections that are used to grind food. There are 3 molars in each quadrant. The last molar is referred to as the wisdom tooth and may be absent in some individuals.

Each tooth has a definite relationship to the surrounding teeth and other oral structures that help it remain in position and function normally.

Children have 20 teeth in all. Each quadrant has 2 incisors, 1 canine and 2 molars. The teeth differ from adult teeth in size and structure.

Anatomy of the tooth and surrounding structures.

Crown; The part of the tooth that lies above the gum line and is visible in the oral cavity

Root: The part of the tooth that lies below the gum line and is embedded in bone. Depending on the tooth, there may be one to three roots. The tip of each root has an opening through which the tooth receives its blood and nerve supply.

Neck: The area that borders the crown and the root is referred to as the neck of the tooth. It is generally close to the gum line.

Enamel: This is the outermost, calcified hard layer of the crown. The enamel is even harder than bone.

Cementum: This is the thin, calcified outermost layer of the root. It provides attachment for ligaments that support the tooth.

Dentin: This is a calcified layer of tooth that lies inside the enamel and cementum. It forms the bulk of the tooth structure in the crown and root.

Pulp: This is the innermost soft tissue core of the tooth which consists of blood vessels, nerves and connective tissue. The pulp is supplied through narrow canals in the roots that lead to openings at the root tips.

Bone: The roots of the teeth are anchored in bony sockets within the alveolar bone of the jaws

Gingiva: The gingiva or gums is soft tissue that surrounds the teeth and covers the surface of the jaws in the oral cavity.

Periodontal ligament: This ligament firmly attaches the root surface to the bony socket holding the tooth in place.

Normal teeth may vary in appearance from individual to individual. Tooth abnormalities can result from various conditions. Maintaining the structure and function of your teeth and their surrounding tissues is necessary for good overall health.