Resorption: clinical presentations, treatment, and etiologic factors

Abstract

Information on dental resorption first appeared in the literature in an 1829 textbook by Thomas Bell. What first was mistaken as bone tumor and known as “absorption,” continues to be one of the most challenging and mysterious phenomena dental clinicians have had to address. Over the past years, there has been a dramatic increase in reports of resorption in the literature, which have aided in the understanding of the condition and its treatments. Resorption is identified by an increase in osteoclastic cell activity that causes a loss of hard dental tissues. As a physiological process, root resorption helps with the eruption and exfoliation of primary teeth. In adults, resorption is of pathological nature. Resorption can happen both internally and externally. External resorption is a much more common occurrence in dentistry than its counterpart, internal resorption, and involves the external aspect of the tooth. External resorption has been subclassified into external inflammatory resorption, external replacement resorption, external cervical resorption, external surface resorption, and transient apical breakdown. Internal resorption is more unusual and more challenging to diagnose and affects the tooth’s pulp chamber and/or its root canal. Internal resorption has been sub-classified as internal inflammatory resorption and internal replacement resorption. Descriptions of the various forms of resorption are numerous in the literature and have become available due to case studies, clinical presentations and treatment options. From trauma, to prolonged orthodontic treatment, to viruses, to genetic and idiopathic factors, there is a variety of possible etiologic causes of both kinds of resorptions that are central to the understanding and treatment of this condition.

Despite the many advances in the field, however, there are still gaps in the processes leading to resorption lesions that remain to be elucidated. If OPG and RANKL are the major culprits in initiating resorption, being able to arrest these molecules or transcription factors, such as c-fos and NFkB or identifying genetic propensities for resorption with a BRCA-like test seem to be research goals which may translate into the prevention of resorption as well as identifying how a physiological process essential to survival transforms into a pathological condition.

Additionally and equally important, when resorption is suspected, there is the need for a thorough examination of the oral cavity and a proper understanding of the underlying pathogenesis for its clinical management. Depending on the extent of the lesion, resorption can be arrested by a variety of endodontic treatments that often include root canals or more complex surgical procedures, such as muco-periosteal flaps that allow the access to the resorptive lesion and the excavation of the granulomatous tissue in the tooth. Moreover, composite, sodium hypochlorite or calcium hydroxide are also employed as treatment/ preventive options as well as breaks in orthodontic procedures to eliminate pressure forces that contribute to and/or cause resorption, pulpectomy, careful monitoring, among others. Whether external or internal resorption, the condition can be treated with high rate of success if caught early. Without intervention, resorption leads to tooth loss.