Endodontic treatment of anterior primary teeth in different sessions

INTERVENTION: Participants are allocated to one of two groups after opening of brown envelopes, previously organized within a randomised sequence. The intervention group receive local anesthesia (Lidocaine 2%), absolute isolation, chemical‐mechanical preparation of the root canals with Milton's solution, second‐series endodontic files, final irrigation with saline solution 0.9%, paste filling (Calcium Hydroxide PA + zinc oxide powder and propylene glycol), gutta percha blade and final restoration with composite resin. The control group also receive local anesthesia (Lidocaine 2%), absolute isolation, chemical‐mechanical preparation of the root canals with Milton's solution, second‐series endodontic files, final irrigation with saline solution 0.9% and paste filling (Calcium Hydroxide PA + zinc oxide powder and propylene glycol), but the restoration is temporary with glass ionomer cement. After 30 days, there is a reintervention in the control group with the exchange of the obturator material, and then the final restoration is done with composite resin. The operator performs blindly during the procedure, since only the group becomes aware of the final moment of use of the sealing paste. The cases have their performances evaluated at 30, 60, 90 days, six months and one year through clinical and radiographic exams. CONDITION: Endodontic treatment of anterior primary teeth. ; Oral Health ; Endodontic treatment PRIMARY OUTCOME: Radiographic lesions are measured using the periapical radiography at the beginning and the end of the study. SECONDARY OUTCOME: Fistula is measured using visual scale at the beginning and the end of the study. INCLUSION CRITERIA: 1. Upper anterior primary teeth 2. Radiographic alteration suggestive of periapical lesion 3. Cavity that allows restorative recovery 4. Without any previous pulp treatment 5. Good systemic health 6. Between 2 and 6 years of age