Any structural anomaly of the cementum, which is the mineralized connective tissue covering the dental root. The cementum allows anchoring of the fibers of the periodontal ligament. Cementum is secreted by cementoblasts, which may be, later on, embedded in the cementum. Cementum can be acellular (along the two third coronal portion of the root) and cellular (in the apical and interradicular part of the root). [ http://www.ncbi.nlm.nih.gov/pubmed/31468724 ]