Root Resorption Classifications: A Narrative Review and a Clinical Aid Proposal for Routine Assessment

Abstract

Root resorption (RR) refers to noninfectious damage related to the loss of hard and soft dental tissue that results from clastic cell activity. It is observed as a pathologic process that is predominantly asymptomatic in the permanent dentition and physiological during the shedding of primary teeth. Roots are protected by unmineralized organic cementoid and predentine. RR occurs because of the inability of the clastic cells to adhere to unmineralized surfaces. Since the first RR classification was described by Andreasen in the 1970s, several classifications have been proposed with diverse terminology. A narrative literature review was undertaken on the current classification, diagnosis, pathophysiology, and treatment of RR. A bibliographic search resulted in 434 titles and abstracts, and from those, 17 articles were obtained that alluded to 15 RR classifications. A total of 28 articles that met the inclusion criteria were included. Results showed that Andreasen's classification is the most widely used for classifying RR. In terms of epidemiologic data, studies are scarce, although RR pathophysiology is well described in the literature. Overall clinical guidelines are summarized in a new RR classification diagram. The choice of RR treatment application should be in line with the RR type and the dentist's experience. However, an earlier and correct diagnosis will significantly improve final outcomes and long-term prognosis, especially with the current evolution of advanced imaging techniques, such as cone-beam computed tomography and bioceramic-based endodontic sealers.

External cervical resorption—a review of pathogenesis and potential predisposing factors

“… 19 With regards to dental hard tissue, the surface of the root is covered by a layer of cementoid, which plays a similar role as the osteoid layer in resisting resorption. 2 Epidemiological studies point out that hypo-mineralization of the cementoid increases the risk of ECR. 10 Besides, histological sections reveal that cementoid is mainly distributed in the apical and middle section of the root.…”

“… 1 Depending on whether the outcome is desirable or not, root resorption can be classified into physiologic and pathologic resorption, the former of which generally refers to root resorption during exfoliation of deciduous teeth. 2 Based on the location of the lesion, pathologic resorption is segmented into external root resorption (ERR) and internal root resorption (IRR). 3 Classifications and terminology regarding external resorption vary across different studies.…”

“…According to the Andreasen Classification, which is by far the most frequently cited in literature, external resorption can be further categorized as inflammatory, replacement, and surface resorption. 2 …”

Management of a perforating internal root resorption using mineral trioxide aggregate: a case report with 5‐year follow‐up

“…Internal root resorption is dependent on two necessary and concomitant pre‐conditions: vitality of the pulp tissue apical to the resorption, and partial or complete necrosis of the pulp tissue coronally (2). The blood supply of the apical vital pulp provides the source for clastic cells and nutrients, while the necrotic tissue serves as the stimulant of the resorptive events mediated by the clastic cells.…”

“…It is a pathologic process that involves, first, a disruption of the outermost protective odontoblast layer and predentin (1). The inflammatory process is only perpetuated while there is a bacteriological stimulus within the canal, namely necrotic pulp tissue coronally to the defect, and vital pulp tissue apically (2). The exact causes of internal resorption are still unknown.…”