The aim of this study is to evaluate the efficacy of CTZ Paste in primary teeth, compared to endodontic treatment with Guedes-Pinto Paste. This is a multicenter, randomized, double-blind (patient), controlled and non-inferiority clinical study on 174 primary molars and 174 primary incisors of 3-6 years-old children with carious lesions with pulp involvement. The sample unit will be the tooth, which will be randomized into two groups. The teeth allocated to the experimental group will be treated with CTZ Paste, whereas the treatment of those teeth allocated to the control group will employ the Guedes-Pinto Paste. The procedures performed will be evaluated clinically and radiographically at 6 and 12 months. Secondary outcomes such as cost, discomfort, satisfaction and quality of life will also be evaluated.

Inclusion Criteria:

• children aged from 3 to 6 years and 11 months;
• children present at least one upper or lower molar or primary upper incisor with untreated carious lesion with pulp envelopment;
• children assent to participate in the study through collaborative behavior;
• children's parents/guardians consent to their participation by signing the Informed Consent Form (ICF).

Exclusion Criteria:

• tooth with carious lesion involving three or more dental surfaces, making the restoration extremely difficult or impossible;
• tooth with internal or external resorption in more than 1/3 of the root length;
• tooth whose crypt of the successor permanent is affected;
• tooth which have less than 2/3 of the root;
• patients who present health problems with oral impairment.