Root resorption is an amalgamation of both physiological or pathological factors leading to the destruction of enamel, dentin, cementum, and the alveolar bone due too polynuclear giant cells. Root resorption has two main types: physiological and pathological. The resorption is physiological only in case of primary dentition just before the teeth are replaced. Pathological resorption can be internal and external. There are many different theories which exist about the etiology of resorption. Normally they are divided into local and systemic causes. Two main pathomechanisms are responsible for the process root resorption: inflammatory and by replacement. External root resorption develops due to a pathological stimulus, which creates a disturbance in the balance between the activity of cementoblasts and that of the osteoclasts.