distal surface of tooth

The distal surface of a tooth is the side facing away from the midline of the dental arch — toward the back of the mouth. Along with the mesial surface, it forms one of the two interproximal surfaces. For the last molar in the arch, the distal surface has no adjacent tooth contact.

The distal surface is located on the posterior-facing side of each tooth within the dental arch. It is oriented away from the front midline, so for front teeth it faces toward the back of the mouth, and for molar teeth it faces the rear of the jaw.

The distal surface maintains proximal contact with the tooth behind it in the arch, helping to stabilize tooth positions and distribute occlusal forces. This contact also prevents food from becoming trapped between teeth. The distal surface of the last molar terminates freely without proximal contact.

Like other interproximal surfaces, the distal surface may be associated with interproximal caries that are difficult to detect without X-rays. Plaque accumulation at the distal gumline may also be associated with localized gingival inflammation or bone loss.

The distal surface is primarily evaluated with dental radiographs, particularly bitewing X-rays, which reveal interproximal caries and bone levels. Periodontal probing around the distal surface assesses gum health, and a dental explorer can detect surface roughness or cavitation during clinical examination.