Calcium Hydroxide as Intercanal Medicament

Ca(OH)2 pastes are used in endodontics as a temporary canal filling material for multiple purposes including:
1. Stimulate continue root development
2. Control exudate/disinfect the canal system
3. Prevention of external root resorption following traumatic injuries
4. Create an apical barrier following over instrumentation

Occasionally, I will use calcium hydroxide as a intracanal medicament to look for signs of initial healing prior to obturation. On this particular retreatment case, the distal canal was long and wide. I was concerned there may have been some resorption or possible an apical crack that I could not visualize.

Pre-Operative Radiograph

Calcium Hydroxide paste was placed (and extruded) in the canals.

3 month recall shows remarkable resorption of the extruded Ca(OH)2 and healing of the apical lesion.

Tooth was re-obturated and another tooth has been saved!

Source:
Cohen & Burns. Pathways of Pulp 6th ed. p.406-407.