Introduction

Approximately one-fourth to one-third of life is spent sleeping or in bed. Sleep has been a mysterious black box that has only recently been extensively studied within the past two decades. While intuitive, sleep has been identified as being important for both physical and mental well-being.^1,2 Disrupted sleep has been implicated in pain syndromes in general and even in temporomandibular disorders.³ The hypothalamus regulates sleep and circadian rhythms with the ventrolateral preoptic (VLPO) nucleus playing a key role.⁴ Sleep disorders can be divided into different categories:⁵

• Insomnia

• Sleep breathing disorders

• Sleep movement disorders

• Parasomnias

• Circadian rhythm disorders

• Hypersomnia