Structure and Junctions
- Cementum is composed of cementocytes, located in lacunae with canaliculi or canals.
- Cementum canals are oriented towards the periodontal ligament and contain cementocytic processes for nutrient diffusion.
- Cementoblasts can form subsequent layers of cementum if the tooth is injured.
- The cementum joins the enamel to form the cementoenamel junction (CEJ).
- The dentinocemental junction (DCJ) is formed by the apposition of cementum over the dentin.
- The attachment of cementum to the dentin is firm but not completely understood.
- The DCJ is a relatively smooth area in the permanent tooth.
- Cementum deposition helps in minor repair of any resorption to maintain attachment.

Types of Cementum
- Acellular extrinsic fiber cementum contains perpendicular collagen fibers and attaches the tooth to the alveolar bone.
- Cellular cementum is thick and contains both extrinsic and intrinsic collagen fibers.
- The first cementum formed during tooth development is acellular extrinsic fiber cementum.
- Main types of cementum include acellular afibrillar cementum, acellular extrinsic fiber cementum, cellular intrinsic fiber cementum, and mixed stratified cementum.

Composition
- Cementum is slightly softer than dentin.
- It consists of about 45-50% inorganic material (hydroxylapatite) and 50-55% organic matter and water.
- The organic portion is primarily composed of collagen and proteoglycans.
- Cementum receives nutrition from the surrounding periodontal ligament.
- Cementum is light yellow and has the highest fluoride content among mineralised tissues.

DNA Studies
- Cementum has five times the amount of mitochondrial DNA compared to dentin.
- DNA extraction and genetic analysis results from dental tissue are variable and unpredictable.
- The quantity of DNA available in dentin is affected by age and dental disease.
- The quantity of DNA available in cementum is not affected by age and dental disease.

Other Information
- Cementum has a dynamic tissue covering of the root.
- Its structure, function, and development have been studied.
- Acellular extrinsic fiber cementum has been analyzed using Raman analysis.
- Cementum is part of the periodontium.
- It has potential functions that are still being explored.