The ability of cementum to repair itself is primarily due to its cellularity and vitality. Cementum contains cementoblasts and cementocytes that remain metabolically active throughout life, enabling continuous deposition and repair. Unlike enamel, cementum’s living cells allow for the formation of new layers in response to injury or wear. This reparative capacity is essential for maintaining periodontal attachment and allows for recovery after minor trauma or resorption. The presence of viable cells within cementum is the key factor distinguishing it from other dental hard tissues in terms of self-repair.

Reference: Oral Histology, B. K. B. Berkovitz, 5th Edition.