External Invasive resorption

Question 1

How common is external invasive resorption?

Answer 1

Rare (0.2% of population)

Question 2

Why does external invasive resorption happen?

Answer 2

Histopathogenesis is obscure and potentially due to multiple factors such as:

Inflammation of gingival crevice

Poorly repaired surface restoration

Accessory canals + toxic/caustic materials

Anatomical variations in the CEJ

Question 3

Which teeth are most commonly affects by external invasive resorption?

Answer 3

5 - 10% of all teeth and 30% of upper incisors

Often attributed to internal bleaching (due to several case reports in the literature) but this was not supported by later studies.

Question 4

What are the features of external invasive resorption?

Answer 4

Sub-gingival - external origin

Radiolucent area - poorly defined margins

Very vascular tissue - bleeds readily

Can resemble caries or internal resorption

Question 5

What causes resorption?

Answer 5

It is caused by invasive tissue, not inflammatory tissue.

Adjacent tissue may become inflamed as a secondary response to the defect on the root surface and plaque retention in the defect.

Question 6

What are potential predisposing factors to external invasive resorption?

Answer 6

Trauma

Intracoronal bleaching

Surgery

Orthodontics

Periodontics

Bruxism

Delayed eruption

Developmental defects

Restorations

Unknown

Question 7

How quick does external invasive resorption progress?

Answer 7

Speed of progression is unknown but appears to be rapid initially and then gets slower later and then works in bursts

Question 8

How is external invasive resorption managed?

Answer 8

Cauterise with Trichloroacetic acid (90%)

Curette the resorption cavity

Restore with GIC (later may need more comprehensive restoration)

Question 9

How is external invasive resorption cauterised?

Answer 9

Using trichloroacetic acid (90%) which kills clastic cells, initiates haemostasis, and helps with visualization.

Question 10

How is external invasive resorption restoration done?

Answer 10

In class 1 a simple restoration can be used.

In class 2 restoration is also needed

Class 3: pulp may be exposed so an RCT is indicated. orthodontic extrusion may also be used to expose and restore the margins.

Class 4 can be left and observed if not causing symptoms and no concurrent pulp disease and no perio problems. Leave until extraction is required then extract. NOTE: There is risk of root fracture.

Question 11

What should be maintained when treating external invasive resorption?

Answer 11

May be advantageous and important to preserve the interdental papilla (especially with anterior teeth)