The periodontium morphological changes under the reduced chewing load influence

The studying the influence of masticatory load on the structure and function of the periodontium is an important area of research in dentistry. Disruption of occlusal relationships, the absence of teeth, or prolonged use of a soft diet led to hypofunction of the masticatory apparatus, which provokes atrophic and dystrophic processes in periodontal tissues. Masticatory load is a key factor maintaining periodontal homeostasis. The aim of this study was to establish patterns of structural and functional reorganization of the periodontium during experimental masticatory hypofunction. The temporal and qualitative characteristics of morphofunctional changes in the periodontium were studied during experimental modeling of masticatory hypofunction. Sixty mature outbred white rats (6 months old, weighing 250300 g) were used in the study. The animals were divided into 2 groups. The main group (n=45) with experimentally modeled masticatory hypofunction, and the control group (n=15) consisted of intact animals. Masticatory hypofunction was simulated by feeding the animals soft food dispersed to a puree state. The experiment lasted 12 weeks. The results were evaluated using a microcomputerized Xray method, histological, immunohistochemical, molecular biological, and biomechanical analyses. After 12 weeks of hypofunction, the bone volume to total bone tissue ratio decreased by 29% (<0.001), indicating pronounced bone resorption. The trabecular thickness decreased by 33%, and the number of trabeculae decreased by 34% (<0.001), which generally confirms a disruption of bone tissue microarchitecture. Histological studies showed that by week 12 of the experiment, the periodontal ligament thickness decreased by 38.7%, the osteocyte count decreased by 42.3%, and the osteoclast count increased by 2.1 times. Molecular biological changes relative to the control included a 0.6fold decrease in the synthesis of the alpha chain of type I collagen and a 0.5fold decrease in alkaline phosphatase activity, as well as a 1.8fold increase in the activity of tartrateresistant acid phosphatase (all changes are significant (p<0.001). The results of the experimental study explain the accelerated tooth loss in patients with unilateral chewing.