Root resorption: classification and therapeutic approach

The clinically crucial distinction between internal and external resorption, the different subcategories of external resorption and their respective treatment approaches, from monitoring to extraction in non-recoverable cases.

Root resorption is a pathological process in which odontoclasts progressively resorb dentin, cementum, or both, with an anatomical distinction of primary clinical importance between internal resorption (originating from the internal surface of the canal, with vital or partially vital pulp sustaining the process) and external resorption (originating from the external surface of the root, typically triggered by damage to the root cementum and overlying periodontal ligament from trauma, excessive orthodontic movement, chronic periapical infection, or intracoronal bleaching procedures with concentrated peroxide).

Internal resorption, radiographically recognizable by the characteristic oval, symmetrical widening of the canal lumen that distorts its normal profile, requires complete removal of the pulp tissue responsible for the process — through conventional canal therapy with particular attention to three-dimensional disinfection of the resorption cavity, often irregular and difficult to shape mechanically — after which the process stops permanently, since it deprives the resorption of the cellular source sustaining it.

External resorption is divided into subcategories with very different prognoses: external inflammatory resorption (typically associated with pulp necrosis and canal infection sustaining the process through exposed dentinal tubules, treatable by stopping the infectious source with canal therapy) has a favorable prognosis if treated early; replacement resorption or ankylosis (in which the periodontal ligament is progressively replaced by bone, with direct fusion between root and alveolar bone) is an irreversible process once started, with progressive and unstoppable loss of the root over the years; invasive cervical resorption (an aggressive lesion originating in the cervical region, below the junctional epithelium, and progressing internally around the pulp until communicating with the canal only in advanced stages) has a prognosis that critically depends on the extent of the lesion at the time of diagnosis.

The therapeutic approach to invasive cervical resorption, classified according to the Heithersay system based on circumferential and in-depth extension, typically involves surgical exposure of the lesion, mechanical removal of the resorptive tissue (often with the aid of the operating microscope for adequate visualization of the margins), and obturation of the residual cavity with bioceramic material — with favorable prognosis in Heithersay class 1-2 lesions, but significantly more guarded in class 3-4 lesions extending close to or within the canal system.

On Oralzon you'll find rotary instrumentation for clearing irregular resorption cavities and bioceramic cements for obturating cervical lesions after surgical removal of pathological tissue.