The Research Of Chronobiology Of Pulp Sensibility In Young And Aged People

Tooth is one kind of demic critical organ. The feeling, nutrition, and reparation of tooth are in the charge of dental pulp. Dental pulp, which is a kind of loose connective tissue in pulp chamber and surrounded by rigid dentine, has abundant innervations to make sensory function available; and human body often feels algaesthesis when pulp nerve is stimulated from outside. Pulp in permanent teeth of young people resists disease and self-repairs easily because of plentiful blood vessels and high vitality. As people grow up, ageing phenomenon emerges in pulp of the aged, including increasing formation of secondary dentin, minification of pulp chamber, meanwhile cell constituent of pulp tapers and fibra constituent multiples, which lead to degeneration of pulp sensibility. It is thus evident that sensory function of pulp is a kind of physiological function in human body; whether it fluctuates according to circadian rhythm? Chronobiology is a newly emerging subject, which studiestemporal rhythm or temporal organization and mechanism regularity in biosystem. In recent years, circadian rhythms with different periodicity have been found in every field of vital movement; kdirlrhythm is a very attractive one in the circadian rhythms studying. Almost all biochemistries, physiologies et al in biosystem run according to kdirlrhythm. Suprachiasmatic nucleus (SCN) of HT is a pacemaker of kdirlrhythm, which is the foundation to generating holo-level circadian rhythms. When accepting rhythmical signals from SCN, periphery oscillator makes special reaction respectively and regulates phases, which may be a result of natural selection and will last forever in the organic evolution process.At present, there are no reports about applying the theory or special statistical analysis of chronobiology to the field of dental pulp research. In China, Pre-research has been explored in 1994, and found that pulp sensibility may fluctuate according to diurnal rhythm and circa-lunar rhythm, but the precision of the examination was low as there was no 24 hours detection.Our research is to testing pulp sensibility threshold of the mandibular first permanent molar in healthy young and aged people, which is performed in 7 time-spots at each 4 hours from 8:00 A.M. to 8:00 A.M. the next day. And the results of each test were averaged to get the mean value. Using the theory of chronobiology and Halberg methods for cosinor-rhythmometry, we will find whether the pulp sensibility of young and aged people fluctuates according to kdirlrhythm. Furthermore, we will fitting kdirlrhythm curves of them,explore the chronobiological characteristic of pulp sensibility according to age changing, approach the relationship between pulp sensibility fluctuatation and vital sign (blood pressure).The study includes 2 examinations:Examination I : The research of chronobiology of pulp sensibility in young people20 healthy young volunteers were examined. Pulp sensibility test was performed using the pulp sensibility tester—NEOSONO Ultima EZ?. Pulp sensibility data was obtained at each 4 hours from 8:00 A.M. to 8:00 A.M. the next day. And the results of every volunteer were analyzed by methods for cosinor-rhythmometry Circadian rhythm is found in pulp sensibility of young people. The highest and the lowest sensibility threshold appear at 0:00 and 12:00 respectively in 24 hours.Examination II: The research of chronobiology of pulp sensibility in aged people20 healthy aged volunteers were examined. Pulp sensibility test was performed using the pulp sensibility tester—NEOSONO Ultima EZ?. Pulp sensibility data was obtained at each 4 hours from 8:00 A.M. to 8:00 A.M. the next day. And the results of every volunteer were analyzed by Methods for cosinor-rhythmometry Circadian rhythm is found in pulp sensibility of aged people. The highest and the lowest sensibility threshold appear at 0:00 and 12:00 respectively in 24hours.Based on these findings, our study succeeds in detecting the rhythmical fluctuate both in the aged and the youth, and by the theory of chronobiology and Halberg methods for cosinor-rhythmometry, we confirms the chronobiological characteristic of pulp sensibility—changing like a cosine curve approximately in 24 hours; and compares the indexes of chronobiology of pulp sensibility between aged and young people, enrich the theory of pulp-chronobiology, which help to guide clinical diagnosis and treatment of pulposis.