Parallel clinical trial focusing on procedural pediatric sedation in the dental setting. Children will be randomized to treatment according to a predetermined sequence of interventions consisting of: 1. intranasal sedation with ketamine-associated dexmedetomidine (Experimental Group), 2. intranasal sedation with dexmedetomidine as sole drug (Control Group). Primary outcome is children's behavior during the dental treatment. Secondary outcomes are: children's pain, memory and stress (salivary cortisol and melatonin); perception of the accompanying adult, dentist and child about dental sedation; cost-effectiveness of this type of sedation; psychosocial variables; children's quality of life.

This proposal aims to determine the most effective pharmacological regimen in the treatment of child pain and anxiety during outpatient dental procedures. Advancement in this field is a reflection, on the one hand, of the use of new and more effective routes of drug administration, such as the intranasal route using atomizers with uniform dispersion of the administered jet and, on the other hand, the use of new sedative drugs, such as dexmedetomidine. This is a randomized, parallel, triple-masked clinical trial, using a research protocol with the objectives: 1) To evaluate the efficacy (behavior, pain, memory and stress) of a sedative regimen intranasally mucosal atomizer device (MAD) using a sedative drug (ketamine) and an innovative drug (dexmedetomidine) in the sedation of children from 2 to 6 years of age undergoing dental treatment - our hypothesis is that the use of dexmedetomidine intranasally association with ketamine is more effective than dexmedetomidine itself in isolation; 2) To analyze the level of cortisol and salivary melatonin (stress) according to each sedative protocol and its association with clinical variables; 3) Identify adverse events with the new protocol; 4) To evaluate the association between the child's behavior and psychosocial variables; 5) To verify the impact of treatment under dental sedation on the quality of life related to the oral health of the child. The research will be carried out in the Faculty of Dentistry of the Federal University of Goias, in the Center of Studies in Dental Sedation (NESO), Goiânia, Goias. A non-probabilistic sample of 88 children aged 2 to 6 years (alpha 0.05, 80% power) who present dental caries with restorative need, American Society of Anesthesiologists I or II, patent nasal airways (Mallampati index I or II and obstruction by hypertrophy of tonsils ≤ 50% and effective nasal breathing), in addition to non-cooperative behavior with the examination or a dental procedure. Children with neuropathies, those using growth hormone and / or those who exhibit severe adverse events during sedation will be excluded. Children will be randomized to treatment according to a predetermined sequence of interventions consisting of: 1. intranasal sedation with ketamine-associated dexmedetomidine (Experimental Group), 2. intranasal sedation with dexmedetomidine as sole drug (Control Group). Pediatricians and anesthesiologists will be aware of the randomized intervention, because of safety concerns for the child, in the case of serious adverse events with or without immediate use of antagonists; the other staff members and the child's companion (s) will be "masked". The examination and intervention sessions will be filmed in high definition for later analysis of the behavior and pain according to different scales consecrated and / or validated. In addition, the children will be submitted to four saliva collections to analyze the levels of cortisol and melatonin (stress-related hormones). Other variables of secondary outcome are: perception of the accompanying adult, dentist and child about dental sedation and cost-effectiveness of this type of sedation, psychosocial variables, quality of life. The data will be analyzed by descriptive and bivariate statistics. This proposal will bring benefits in the vast field of health sedation by having original design, using drugs and promising routes, with national and international impact. The project is inserted in a research line that presents experience history and impact publications by the proponent team, as well as involving students of scientific initiation, master's, doctorate, and postdoctoral studies, being developed by a multidisciplinary team. There is a clear expectation of generating results with high impact production, besides the possibility of immediate application in the public and private sectors of a highly effective sedative regime, minimizing the need to refer patients to general anesthesia.

Inclusion Criteria:

• Children born to term, whose physical condition is categorized as American Society of Anesthesiologists I (healthy) or II (mild and controlled systemic disease - persistent asthma, for example)
• Children with a low risk of airway obstruction (Mallampati less than 2 and / or tonsil hypertrophy occupying less than 50% of the oropharynx)
• Children without neurological or cognitive alterations and who do not use medications that may compromise cognitive functions
• Children with caries requiring dental restoration

Exclusion Criteria:

• Children with positive behavior in the consultation without sedation
• Children with facial deformity
• Children using corticosteroid