Circadian clock—A promising scientific target in oral science

Abstract

The oral and maxillofacial organs play vital roles in chewing, maintaining facial beauty, and speaking. Almost all physiological processes display circadian rhythms that are driven by the circadian clock, allowing organisms to adapt to the changing environment. In recent years, increasing evidence has shown that the circadian clock system participates in oral and maxillofacial physiological and pathological processes, such as jaw and tooth development, salivary gland function, craniofacial malformations, oral carcinoma and other diseases. However, the roles of the circadian clock in oral science have not yet been comprehensively reviewed. Therefore, This paper provides a systematic and integrated perspective on the function of the circadian clock in the fields of oral science, reviews recent advances in terms of the circadian clock in oral and maxillofacial development and disease, dialectically analyzes the importance of the circadian clock system and circadian rhythm to the activities of oral and maxillofacial tissues, and focuses on analyzing the mechanism of the circadian clock in the maintenance of oral health, affecting the common diseases of the oral and maxillofacial region and the process of oral-related systemic diseases, sums up the chronotherapy and preventive measures for oral-related diseases based on changes in tissue activity circadian rhythms, meanwhile, comes up with a new viewpoint to promote oral health and human health.

Effect and potential mechanism of p75NTR in the regulation of the circadian rhythm and daily mineralization during tooth development

“…It was reported that complete SCN lesions result in the disappearance or disturbance of daily growth lines in rat incisors 15 . In addition, an increasing number of clock genes, such as Bmal1, Clock, Per, and Cry, have been reported to be expressed in tooth germs 20,37,53 . These studies further con rm the effects of the circadian rhythm on tooth development.…”

“…The presence of these incremental growth lines suggests that dentin/enamel formation and maturation are under circadian control. Several studies 15,19,20 have reported that the clock genes Bmal1, Clock, Per, and Cry are detected in different stages during tooth development and oscillate at regular 24-hour intervals. Moreover, several odontogenesis-related factors (e.g., ameloblastin, amelogenin, and lysosomeassociated membrane protein) have been reported to exhibit regular oscillating expression patterns in rat tooth germs at postnatal day 1 (PN1) 5,21,22 .…”

The Relationship between Sleep, Chronotype, and Dental Caries—A Narrative Review

“…A decreased quantity or quality of saliva can increase the risk of dental caries [ 50 ]. Saliva is essential for regulating the oral microbiome and maintaining oral health, especially in preventing oral diseases and controlling oral infections [ 51 ]. Normal saliva secretion and saliva flow are directly related to oral health.…”

“…Normal saliva secretion and saliva flow are directly related to oral health. Decreased saliva flow is an important indicator of oral health, and disorders of the salivary glands are the main factor affecting the decrease in saliva flow [ 51 ]. Saliva has the most significant influence on caries’ progression [ 52 ].…”

“…Saliva flow is weak in the morning, increases in the afternoon, and then decreases [ 57 ]. The circadian rhythm of the salivary glands plays a vital role in controlling food intake and the immune system because it affects the flow of saliva and the ionic composition [ 51 , 58 ]. Changes in saliva flow and composition can affect oral health, as saliva helps to neutralize acids produced by oral bacteria, remineralize tooth enamel, and lubricate the mouth [ 59 ].…”