Tooth resorption

Tooth resorption is a common sequela following injuries to or irritation of the periodontal ligament and/or tooth pulp. The course of tooth resorption involves an elaborate interaction among inflammatory cells, resorbing cell s, and hard tissue structures. The key cells involved in resorption are of the elastic type, which include osteoblasts and odontoclasts. Types of toot h resorption include, internal resorption and external resorption. There ar e two types of internal resorption: root canal (internal) replacement resor ption and internal inflammatory resorption. External resorption can be clas sified into four categories by its clinical and histologic manifestations: external surface resorption, external inflammatory root resorption, replace ment resorption, and ankylosis. External inflammatory root resorption can b e further categorized into cervical resorption with or without a vital pulp (invasive cervical root resorption) and external apical root resorption. O ther variations of resorption include combined internal and external resorp tion and transient apical breakdown.