Determinants of probable sleep bruxism in a pediatric mixed dentition population: a multivariate analysis of mouth vs. nasal breathing, tongue mobility, and tonsil size

Abstract

ObjectivesThis study aims to identify structural and functional craniofacial characteristics that correlate with higher incidence of ‘probable’ sleep bruxism in children. MethodsFrom March 2018 until March 2019, a cross-sectional clinical study was performed with ninety-six healthy children ages 6–12 years who presented for routine dental examination at the UCLA pediatric dental clinic. Variables of interest included: (1) assessment of probable bruxism based on parental awareness on the frequency of tooth grinding during sleep and clinical signs of bruxism based on tooth wear; (2) parental reports of mouth breathing while awake and asleep, snoring during sleep, difficulty breathing and/or gasping for air during sleep; (3) parental reports of psychosocial distress; (4) assessment of tonsil hypertrophy, tongue mobility, and nasal obstruction. Three pediatric dental residents were calibrated to perform the clinical data collection. All dental residents were graduated dentists with licensure and at least one year of experience examining children. The methodology to take the specific measurements administered in the manuscript were calibrated between the data-collectors under the supervision of a board-certified pediatric dentist and orthodontist (AY). ResultsThe mean age of individuals was 8.9 (SD = 1.9) years with a gender distribution of 46 males and 50 females. There were 23 out of the 96 (24%) individuals who met the diagnostic criteria for probable sleep bruxism (PSB). Sleep Disturbance Scale for Children (SDSC) scores were significantly elevated among children positive for PSB, indicating that they are at higher risk for sleep disturbances (PSB-positive: 45.1 ± 13.0, PSB-negative: 34.8 ± 5.5; p < 0.0001). Impaired nasal breathing, parental reports of mouth breathing when awake or asleep, restricted tongue mobility, and tonsillar hypertrophy were found to be significant risk factors for PSB. Exploratory analysis further suggests a synergistic effect between tonsil hypertrophy, restricted tongue mobility, and nasal obstruction. The incidence of probable sleep bruxism among individuals without any of the exam findings of tonsillar hypertrophy, restricted tongue mobility, and nasal obstruction was 5/58 (8.6%), whereas the incidence of PSB among individuals with all three exam findings was 10/11 (90.9%), p < 0.0001. Among the 23 individuals with PSB, however, there were n = 5 (21.7%) who did not have any of the three exam findings, suggesting an additional role of psychosocial distress, postural maladaptation, malocclusion, or other factors in the etiology of sleep bruxism. ConclusionThis study shows that tonsil hypertrophy, restricted tongue mobility, and nasal obstruction may have a synergistic association on the presentation of PSB. Dentists should evaluate for tonsillar hypertrophy, restricted tongue mobility, and nasal obstruction in the evaluation of PSB, as these exam findings are highly prevalent in the majority of cases.