Regeneration is defined as reproduction or reconstitution of a lost or injured part, whereas repair is defined as healing by a tissue that does not fully restore the architecture or function of the part. New attachment is defined as the union of connective tissue or epithelium with a root surface that has been deprived of its original attachment apparatus. On the other hand, Reattachment describes the union of epithelium or connective tissue with a root surface. Regeneration of periodontal tissues lost to periodontal disease is somewhat an intangible goal in periodontal therapy.