Prevalence of Sleep Bruxism and its Association with Sleep Quality and different Chronotype Profiles of Preschool Children in Lucknow city: A Cross-Sectional study.

Bruxism is a repetitive jaw-muscle activity with clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. The term bruxism was derived from the Greek word ‘brychein’ meaning grinding the teeth. Marie, Pietkiewicz in 1907 used the term ‘la bruxomanie’ in French.

This condition affects both children and adults. Bruxism has two distinct circadian manifestations. It can occur during waking hours (Day Time Bruxism/Diurnal bruxism /Awake Bruxism) or during sleep (Nighttime bruxism/Nocturnal bruxism/ sleep bruxism).

The global bruxism (sleep and awake) prevalence is 22.22%. The global sleep bruxism prevalence is 21% and awake prevalence is 23%.The onset of sleep bruxism is about 1 year of age soon after the eruption of deciduous incisors. The prevalence of sleep bruxism is reported to be 10-20% in children.In preschool children, it is found to be prevalent at 14% and it decreases with advancing age. In young adults aged between 18 and 29 years, it is 13% and 3% in individuals over 60 years of age. The disorder appears more in children with primary dentition. It is usually short-term; often stops by the time secondary dentition erupts.

The etiology of bruxism is multifactorial. It includes psychological/ behavioral factors such as stress and anxiety. Social factors like divorced/Single parents, problems at school, high expectation of academic performance by teachers/parents, abusive environment of the child, the birth of a sibling can also contribute to bruxism. Systemic factors such as allergies, asthma, intestinal parasite infestation, nutritional or endocrine disorders, and dental factors like malocclusion, TMJ dysfunction can be causative towards bruxism.

Although the condition is self-limiting in many children, it may contribute to tooth wear, enamel loss, tooth sensitivity, muscular discomfort, TMJ pain, and disturbed sleep quality. Furthermore, bruxism may reflect underlying behavioural or psychological stress, making it a useful early marker of psychosocial issue in children.

Lucknow, as a major urban and educational centre in northern India, represents a diverse pediatric population increasingly exposed to modern lifestyle patterns such as extended screen use, irregular sleep schedules, heightened academic expectations, and changing family dynamics—all of which may influence children’s sleep quality and behavior. These conditions may predispose preschool children to sleep disturbances and bruxism. Despite its clinical relevance, there are no publishedstudies from Lucknow evaluating the prevalence and associated factors of sleep bruxism among children. However, there is a paucity of Indian data exploring this condition among preschool aged children. Most Indian studies focus on school-aged populations, leaving a significant gap in understanding its occurrence during early childhood a period when parafunctional habits typically originate.