Hypercementosis is an idiopathic, non-neoplastic condition characterized by the excessive buildup of normal cementum (calcified tissue) on the roots of one or more teeth. A thicker layer of cementum can give the tooth an enlarged appearance, mainly occurring at the apex or apices of the tooth. The cellular cementum functions at the bottom half of the tooth roots which contain cementocytes that anchor the tooth into the jaw socket, protect the tooth's pulp, and repair external root resorption.

It is experienced as an uncomfortable sensation in the tooth, followed by an aching pain. Excess amounts of cementum may cause pressure on periodontal ligaments and adjacent teeth. The teeth affected may present as asymptomatic. It may be shown on radiographs as a radiopaque (or lighter) mass at each root apex to confirm the diagnosis.

Trauma and other developmental disorders such as Paget's disease may be more prone to develop hypercementosis in the maxillary region.

Local factors:

Systemic factors:

It may be one of the complications of Paget's disease of bone in the form of generalized hypercementosis.

It may also be a compensatory mechanism in response to attrition to increase occlusal tooth height.

Research has suggested that mutations in the ENPP1 and GACI genes may contribute to the development of hypercementosis. Loss of function in ENPP1 caused generalized arterial calcification of infancy (GACI) which was directly associated with individuals with hypercementosis. When ENPP1 is inhibited, there is a deficiency in pyrophosphate (PPi) that regulates the mineralization of bone by stopping hydroxyapatite crystals from forming. PPi naturally inhibits crystal formation in inappropriate areas such as in the sub-gingival area. Loss of control in PPi may result in excessive cementum deposition in the lower third of the tooth.