Obstructive Sleep Apnea (OSA) is a severe condition of sleep respiratory disorders. It is characterized by partial (hypopnea) or total (apnea) obstruction of the upper airways, negatively affecting the general and oral health of children and adolescents. The Dentistry plays a fundamental role in OSA diagnosis and early intervention, minimizing health damage and progression of the disease into adulthood. Current scientific evidence related to OSA and associated factors, as well as the prevalence and severity of the disease in children and adolescents is still scarce and presents divergences in these age groups. A retrospective cross-sectional study will be conducted to investigate the prevalence, severity and correlation between sociodemographic, behavioral, clinical and sleep quality related factors and OSA in children and adolescents diagnosed by polysomnography (PSG), using the criteria recommended by the American Academy of Sleep Medicine (AASM). The sample will consist of individuals who answered the questionnaires, performed the PSG at the Pelotas Sleep Institute and met the study inclusion criteria.

Obstructive Sleep Apnea (OSA) is a severe condition among sleep respiratory disorders, characterized by intermittent episodes of partial (hypopnea) or total (apnea) obstruction of the upper airways during sleep. These obstructive episodes result in hypoxemia and hypercapnia, changes in intrathoracic pressure and sleep arousals, consequently leading sleep fragmentation and a non-restorative sleep pattern.

OSA affects 1 to 4% of the world's pediatric population, with a higher incidence between 2 to 8 years old, negatively affecting the general and oral health of children and adolescents. Studies show divergences regarding the prevalence among sexes, either showing similar rates for girls and boys, or a predilection of the disease for the male sex. Although scientific evidence reports known OSAs risk factors like adenotonsilar hypertrophy and obesity, there is still divergence of which associated characteristics are present in children and adolescents.

Diagnostic criteria of OSA in this population follows the recommendations of American Academy of Sleep Medicine (AASM) through the International Classification of Sleep Disorders (ICSD-3), which determines full-night PSG as the gold standard test for the diagnosis and severity of OSA, as it promotes a quantitative and objective assessment of disturbances in breathing and sleep patterns. Although parents' report of child behavior and symptoms is essential for establishing the diagnosis of OSA, the factors evaluated in the anamnesis and clinical examination, in general, do not present adequate accuracy for the diagnosis of OSA. The use of clinical history and physical examination alone is not suitable for a definite diagnose of OSA when compared to PSG. Besides, most questionnaires used as alternative diagnostic methods do not meet the necessary criteria to be considered as acceptable tools in the identification of children and adolescents with OSA.

There is evidence in the literature regarding OSA's significant morbidity in children and adolescents, leading to cardiovascular, metabolic and neurocognitive complications, resulting in reduced quality of life. Also, OSA is associated with several craniofacial and dental changes, such as retrognathia, class II malocclusion, vertical face growth and sleep bruxism. It becomes clear the importance of the dentist in identifying factors associated with OSA in children and adolescents, this being the first step towards early and definitive diagnosis, followed by adequate treatment, to minimize the health damage in this population. Therefore, this study aims to study the risk factors correlated with OSA, the prevalence and severity of illness in children and adolescents, considering that the current scientific evidence is divergent.

A retrospective cross-sectional study will be conducted to investigate the prevalence, severity and associations between diagnosis by gold-standard PSG examination and the sociodemographic, clinical conditions, sleep quality and sleep structure of children and adolescents, following the recommended criteria by the AASM. Also, this study aims to evaluate the association of sleep bruxism (SB) and OSA. The sample will consist of participants, between 1 and 18 years, who were referred to Pelotas Sleep Institute, answered the questionnaires (self-reported or parent-reported) and performed PSG for diagnostic purposes.

Inclusion Criteria:

• Children (1 to 11 years) and adolescents (12 to 18 years), who were referred to a sleep laboratory
• Participants who performed polysomnography and answered questionnaires (self-reported or parent-reported) at Pelotas Sleep Institute.

Exclusion Criteria:

• Participants who present a history of syndromes, neuromuscular or neurological disorders;
• Participants whose questionnaires were not completed.

Participants in the child and adolescent age group, referred to the Pelotas Sleep Institute for polysomnography in the period from January 2012 to December 2017.