Circadian dynamics in the functional interaction of the lateral teeth occlusal surfaces' relief.

ABSTRACT

Aim: This study describes the relationship of the chronophysiological organization of the lateral teeth occlusion and the parameters of the chewing unit of the human dentofacial system (bioelectric potentials, the force of the masticatory muscles, masticatory efficiency) which should be considered in modeling of prosthesis occlusal surfaces. Materials and Methods: Examination of 200 respondents with a "day" chronotype, with Angle class I bilateral occlusion at the age of 18-35 years was conducted daily for 3 days. From 8.00 to 20.00, every 4 hours, the amplitude of the electromyography, the jaw muscles' force, the masticatory efficiency, the area of the occlusal contacts, and the near-contact zones were determined. Results: The activity of the masticatory muscles increased during the period from 12.00 to 16.00, which coincided with the escalation of the masticatory efficiency and of the occlusal contacts area. The relationship between the occlusal surfaces' relief and masticatory efficiency is described by two types of occlusal surfaces' topography - smoothed and pronounced, differing by the ratio of the areas of the occlusal contacts and the near-contact zones in 0.25- and 1-mm wide. Conclusion: The modeling of the occlusal surface of the permanent prosthetic restorations for patients with the "day" chronotype should be carried out with the area values of occlusal contacts and near-contact zones corresponding to the period of masticatory muscles activity from 12.00 to 16.00 and in accordance with the characteristic type of the occlusal surfaces' relief.