Interrelationships between morphometric, densitometric, and mechanical properties of mandible in 6-month-old male pigs

Abstract

The aim of the study was to evaluate interrelationships between final body weight, and morphometric, densitometric, and mechanical properties of the mandible in 6-month-old Polish Large White pigs exposed to dexamethasone and nanocalcium. The study was performed on 27 males, castrated on the 28th d after weaning, and reared until the age of 6 months, after which the animals were slaughtered, and the mandible was obtained. The pigs were divided into four experimental groups: animals given per os nanopartical calcium, animals injected with dexamethasone, animals given both nanopartical calcium per os and dexamethasone injections, and animals injected with placebo. After the slaughter, morphological properties of the mandible such as bone weight and length were determined. Using computed tomography technique, volumetric bone mineral density (vBMD) of the cortical bone (Cd), mean volumetric bone mineral density (MvBMD), and total bone volume (Bvol) of whole mandible were measured. Areal bone mineral density (BMD) and bone mineral content were evaluated with the use of dual-energy X-ray absorptiometric method. Using three-point bending test, mechanical parameters such as maximum elastic strength (Wy) and ultimate strength (Wf) of mandible were estimated. Pearson's correlation coefficient (r) was determined between all the investigated variables. The obtained results showed a significantly positive correlation between body weight and mandible weight, mandible length, Bvol, Cd, BMD, BMC, Wy, and Wf. However, statistically insignificant correlations of MvBMD and body weight, mandible weight, mandible length, and Bvol were observed. Furthermore, Bvol and Cd were not found to be significantly correlated. In conclusion, this study showed numerous positive correlations between final body weight and densitometric, morphometric, and mechanical properties of the mandible. This bone of pigs may be used as an attractive model for further investigation on metabolic response of the skeleton to physiological, nutritional, toxicological, and pharmacological factors influencing bone tissue metabolism.