Pulp therapy aims to sustain the teeth where pulp tissue is affected by caries, dental trauma, or other causes in a functional state. When the pulp has become irreversibly infected or necrotic, a root canal treatment is indicated. In endodontic therapy of primary teeth, due to the tortuous and complex character of root canals and the change in their morphology with root resorption, 'biomechanical preparation' is restricted only to debridement of the root canals.