Internal & External Resorption

Resorption of tooth is the process that involves breaking down the tooth either internally or externally. Generally the cause is unknown and may result is some unwanted consequences (Figure 1). Radiographically its defined as an area of radiolucency.

Figure 1
Figure 1: External Resorption


  • Internal Resorption

Resorption of the dentin of the pulpal walls may be seen as part of an inflammatory response to pulpal injury, or it may be seen in which no apparent trigger can be identified (Figure 2 & 3).

Figure 2: Internal Resorption.
Figure 2: Internal Resorption.
Figure 3: Internal Resorption.
Figure 3: Internal Resorption.

The resorption occurs as a result of activation of osteoclasts or dentinoclasts (Tooth resorping cells) on internal surfaces of the root or crown. In time, the root or crown is perforated by the process, making the tooth useless.

Any tooth may be involved, and usually only a single tooth is affected, although cases in which more than one teeth involved have been described. In advanced cases, teeth may appear pink because of the proximity of pulp tissue to the tooth surface. Until root fracture or communication with a periodontal pocket occurs, patients generally have no symptoms.

The treatment of choice is root canal therapy before perforation. Once communication between pulp and periodontal ligament occurs, the prognosis for saving the tooth is very poor. Occasionally, the process may spontaneously stop for no apparent reason.

  • External Resorption

Resorption of teeth external surfaces may have one of several causes (Figure 4, 5,6,7, & 8).

Figure 4: External Resorption.
Figure 4: External resorption.
Figure 5: External Resorption, cervical area.
Figure 5: External resorption, cervical area.
Figure 6: External Resorption, apical.
Figure 6: External resorption, apical.
Figure 8: External Resorption of an impacted tooth.
Figure 7: External resorption of an impacted tooth.
Figure 9: External resorption induced by a central giant cell granuloma (a small area of inflammation in tissue).
Figure 8: External resorption induced by a central giant cell granuloma (a small area of inflammation in tissue).

This change may be the result of an adjacent pathologic process, such as:

  1. Chronic inflammatory lesions.
  2. Cysts.
  3. Benign tumors.
  4. Malignant neoplasms (tumors).

The pathogenesis of external resorption from these causes has been related to the release of chemical mediators, increased vascularity, and pressure. External Resorption of teeth may also be seen in association with:

  1. Trauma.
  2. Reimplantation or transplantation of teeth.
  3. Impaction.

Trauma that causes injury to or necrosis (death of tissue) of the periodontal ligament may initiate resorption of tooth roots. This trauma may result from a single event, from malocclusion, or from excessive orthodontic forces. Because reimplanted and transplanted teeth are nonvital and have no surrounding viable periodontal ligament, they eventually are resorbed and replaced by bone. Impacted teeth, when they impinge or exert pressure on adjacent teeth, may cause root resorption of the otherwise normally erupted tooth. Impacted teeth themselves occasionally may undergo resorption. This cause of this phenomenon is unknown, although it is believed to be related to partial loss of the protective effect of periodontal ligament or reduced enamel epithelium (overlies a developing tooth).

Finally, external resorption of erupted teeth may be idiopathic (unknown). This may occur in one or more teeth. Any tooth may be involved, although molars are least to be affected. One of two patterns may be seen.

  1. Resorption occurs immediately apical to the cementoenamel junction, mimicking a pattern of caries associated with xerostomia (dry mouth). In external resorption, however, the lesions occur on root surfaces below the gingival epithelium attachment.
  2. In the other pattern of external resorption, the process starts at the tooth apex and progress occlusally.

External resorption is a particularly frustrating part of dental abnormality for both patients and practitioners because there is no plausible or evident explanation for the condition and no effective treatment. Over an extended clinical course, resorption eventually causes loss of affected tooth.

Reference: Oral Pathology, Sixth Edition, By Regezi, Sciubba, & Jordan.

Now i want to hear from you!

Have you ever experienced resorption in one of your tooth? & what measures have you follow to stop the process?

I read each & every comment.

Haider Maitham, DDS


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