Simulation of the effect of dental modifications on facial soft tissues: a 3D stereophotogrammetric study

The aim of the present paper is to briefl y review the changes occurring in the nucleus tractus solitarii and carotid body in response to hypoxic and hyperoxic injuries. Selective alterations of dendrites and Fosimmunoreactivity of neurons have been observed in the subnucleus gelatinosus of the nucleus tractus solitarii of adult subjects dying after hypoxicischaemic injury. The selective vulnerability of this portion of the nucleus tractus solitarii may be explained mainly with reference to the vascularization of medullary tegmentum. In the carotid body, chronic hypoxia and hyperoxia cause a series of morphological, cellular and biochemical changes which may play a major role during the first postnatal period and may have implications in the pathogenesis of Sudden Infant Death Syndrome. Intermittent hypoxia may cause hypersensitivity of the carotid body, possibly increasing the risk of unstable respiration. Conversely, hyperoxia exposure has been reported to cause hyposensitivity and reduction in volume of the carotid body, possibly leading to ineffective response.