Idiopathic external apical root resorption: a case report and review of the literature

Root resorption seen within the orthodontic population is usually due to pathology, such as that seen in tooth impaction or trauma, or as a consequence of orthodontic treatment itself.¹ Brezniack and Wasserstein² described four types of root resorption: physiological, inflammatory, replacement and idiopathic resorption. This review of the literature aims to describe the current evidence available for idiopathic root resorption and includes the presentation of an interesting case with idiopathic external apical root resorption (IEARR), which appears to be limited to teeth not in occlusal function.

Root resorption has a complex and multifactorial aetiology.¹ It occurs as a result of localized inflammation and may have a transient or progressive presentation. It is a complex process in which hard tissue dentine and cementum are lost, usually following localized damage or loss of periodontal ligament³ which is believed to play a protective role maintaining the integrity of the root.⁴ Dentinoclasts are known to be involved in root resorption, which may be mediated by prostaglandins, bacterial products, macrophage chemotactic factors and osteoclast-activating factors⁵ following the loss of the protective periodontal ligament element. Dentinoclasts differ from bone-resorbing osteoclasts in that they are smaller, have fewer nuclei and less defined zones of active resorption.⁴ Transient root resorption is not uncommon and it has been suggested that this is self-limiting in the absence of constant stimulation with cemental-tissue repair.⁴ Loe and Waerhaug⁶ suggested that, when multiple teeth show evidence of root resorption, this could be a sign that dental hard tissues have become involved in the osseous process of remodelling.