Internal replacement (invasive) resorption

This type of resorption is relatively rare
and may appear clinically as a pink area in the crown of the
affected tooth as shown in Fig 20a. However, the
clinician should recognize that a pink appearance in the
crown of a tooth is indicative of highly vascular
resorbing tissue which has removed sufficient dentine
and enamel to allow it to be visible through the thin
overlying tooth substance. While this may be internal in
origin, particularly if there has been a history of recent
trauma, it more commonly arises from an external
periodontal source. The location of the pink spot is
more likely to be entirely within the crown of the tooth
in internal replacement (invasive) resorption.

Hyperplastic invasive resorptions

The third group of dental resorptions are insidious in

nature and generally present complex therapeutic

challenges. In these cases, resorbing tissue invades the

hard tissues of the tooth in a destructive, and apparently

uncontrolled fashion, akin to the nature of some fibro-osseous 

lesions such as fibrous dysplasia.

An important distinguishing factor for this third group of

resorptions is that, unlike the first two types of

resorption, simple elimination of the cause of the lesion

is ineffective in arresting their progress. Total removal

or inactivation of the resorptive tissue is essential if

recurrence (or concurrence) is to be avoided.

Concurrence indicates the incomplete removal of the

resorptive tissue at the time of treatment and recurrence

is the re-establishment of the resorptive process. The

reason for recurrence or concurrence is probably due to

the invasive nature of the resorptive tissue whereby

small infiltrative channels are created within the  dentine

and these may interconnect with the periodontal

ligament in positions more apical to the main resorptive

defect.

Unless the tissue in these infiltrative channels is

inactivated the resorptive process will continue. While

these resorptions are not considered to be neoplastic,

their aggressive characteristics can seem to be similar.

At the present time one proven therapy for inactivation

is chemical in nature but surgical and other

technological modalities may also be applied.

These hyperplastic invasive resorptions may have a

pulpal (internal) or a periodontal origin (external).

Critical to the clinical use of therapies aimed at

controlling internal and external invasive tooth

resorptions is the correct diagnosis of the type and

localization of the resorption.

Hyperplastic resorptions may be subdivided into

internal replacement (invasive) resorption, invasive

coronal resorption, invasive cervical resorption and

invasive radicular resorption.