Chronodentistry through orthodontic perspective: A literature review

The human body possesses a unique set of machinery called the molecular/biological clocks that function on a regular 24-h basis forming a circadian rhythm (CR). This aids in coordinating the human biological system with ever-changing environmental conditions, thereby maintaining a balance in its functioning. The central/core component of this system is known to be in the suprachiasmatic nucleus of the hypothalamus with a few aides in the periphery. The periodontal ligament in humans, being one of the dynamic oral tissues, has been shown to exhibit this self-sustained, innate oscillatory behavior that has gained significant attention from dental surgeons. Though substantial evidence regarding its precise role in maintaining circadian periodicity is still unclear, its indispensable role in dentofacial functioning cannot be denied. This review is an attempt in bringing to light the possible role of circadian periodicity in the functioning of oral tissues in the field of orthodontics with a special focus on its role in bone remodeling, orthodontic tooth movement, orthopedic and functional appliances, pain management, and their clinical implications. This could provide a better understanding of the various physiologic and pathologic processes and help us refine our approach toward orthodontic diagnosis and therapeutics. This review would therefore serve as an overview, opening more avenues for further research on this topic that can greatly help the orthodontic fraternity.