Morphofunctional restructuring of periodontal tissues with reduced occlusal load (experimental study)

Relevance of the problem. Reduced masticatory load is recognized as an important etiological factor in the development of periodontal pathol ogies. However, comprehensive studies combining data on morphological, molecular, and biomechanical changes over time remain relevant. Objective: To conduct a comprehensive analysis of structural and functional changes in periodontal tissues under conditions of experimentally induced masticatory hypofunction. Materials and methods: a controlled experiment on 60 mature rats We modeled masticatory hypofunction by switching animals to a soft diet for 12 weeks. Micro-CT, histology, immunohistochemistry (RANKL, OPG), mRNA expression assessment (COL1A1, ALP, TRAP), and biomechanical testing were used for evaluation. Results. Hypofunction was found to cause significant periodontal remodeling: a decrease in bone volume density (BV/TV) by 31.5%, trabecular thickness (Tb.Th) by 35.8%, and their number (Tb.N) by 36.1% (p < 0.001). Periodontal ligament atrophy with a 41.2% decrease in thickness was detected. Immunohistochemical analysis showed a 2.5-fold increase in RANKL expression and a 34% decrease in OPG, which correlated with a 2.1-fold increase in TRAP activity. times. A decrease in the expression of COL1A1 (0.55-fold) and ALP (0.45-fold) confirmed the suppression of bone formation. Biomechanical parameters demonstrate a decrease in the elastic modulus of the periodontal ligament and tooth stability by 42.5 and 41.8%, respectively. Conclusion. The obtained data reveal the pathogenetic mechanisms of structural degradation of the periodontium during hypofunction, which explains accelerated tooth loss and substantiates the need for adequate functional loading to maintain its homeostasis.