Bone Abstracts

Objective: The purpose of this study was to determine the impact of age on the ultrastructural, histological, biomechanical, and biochemical changes of bone tissue in rats.

Methods: The study included 24 female rats of two age groups: Group A (Young) of 5-month old rats and Group B (Old) of 18-month old rats. Radiomorphometric assessment of the hydroxyapatite was used to investigate the ultrastructure of the alveolar bone tissue. Biomechanical and biochemical changes were measured; histological and histomorphometrical evaluations were made.

Results: There was an increase in the size of the hydroxyapatite crystals and their shape as well as the bonds with collagen type I molecules and the organic matrix of bone tissue in older rats compared to young rats. The biomechanical characteristics of the alveolar process and the mandible deteriorated as evidenced by the decrease in ultimate strength (374.94±27.99 GPa compared to 407.44±17.97 GPa) and elasticity coefficient (16.3±1.5 GPa compared to 21.2±1.2 GPa; P<0.05). Index work of bonre destruction was 75.24±2.28 mJ in old rats compared to 70.66±3.09 in the young rats. The height of the jaw and alveolar process were higher in old rats compared to young animals (7.18+0.07 mm vs 6.18+0.07; P<0.01). The thickness of alveolar process in cervical area were significantly higher in old rats 302.19±1.02 microns, compared to 262.22±1.62 microns in young rats (P <0.01).

Conclusion: Ultrastructural organization of bone tissue of the alveolar process and the jaw deteriorate with age, which leads to a weakening of the biomechanical characteristics of bone tissue. The degradation of bone tissue with age may contribute to the development of adaptive reactions in bone tissue and is aimed at increasing the volume of bone tissue, increasing the height of the jaw and alveolar process and thickness in the counterfort areas, and maintaining its function (chewing).