Dynamic response of the left and right laminae of the vertebral arch during unilateral occlusion

Abstract

In order to evaluate deformation of the cervical vertebra during unilateral occlusion, we placed strain gauges on the right and left laminae of the first, second and third cervical vertebrae in monkeys.We electrically stimulated the bilateral masseter muscles of the anesthetized animals to produce mild, intermediate and strong occlusal forces by inserting 3mm and 7mm thick wood chips between the left maxillary and mandibular first molars.As the thickness of the chip and the occlusal force increased, the first cervical vertebra tended to lean toward the working side while the second cervical vertebra leaned in the opposite direction.The results showed that the odontoid process of the second cervical vertebra plays an extremely important role in maintaining posture of the head and neck during occlusion and mastication.