Root resorption of dental and traumatic origin: classification based on etiology.

While root resorption is a relatively common complication of dental trauma, classifications of root resorption are inconsistent and confusing. All pathological root resorption of dental origin is inflammatory in nature. For root resorption to occur, the protective superficial layer must be (internally or externally) damaged or changed and an inflammatory stimulator must be present. This article attempts to classify root resorption on the basis of etiology, i.e., the cause of the protective layer loss and the cause of the inflammatory response, to facilitate more efficient treatment.