ABSTRACT
Bone is a remarkable connective tissue that possesses the quality to undergo the process of remodeling to maintain its mass and structure depending on mechanical loading, however not all bones are subjected to mechanical loading yet they don't show disuse osteoporosis. In oral biology, tooth removal leads to alveolar bone resorption due to reduced mechanical load [like limb bone], however basal bone does not resorb so quickly on disuse despite the fact that there is less mechanical load on it [like calvaria]. So in this respect, mandible display features of both the limb bone and calvaria. Therefore the aim was to compare the amino acids composition of mandible with ulna and calvaria and the objective was to compare the bone samples with collagen standard. The commercial collagen type I from the rat tail tendon [sigma Aldrich, UK] was used as a reference to be compared with the bone samples. These samples were subjected to carbon-13 NMR spectroscopy. Results showed that the carbon-13 spectra of ulna and calvaria were almost similar, while mandibular spectra showed the most distinct results. Carbon-13 NMR study showed increased proline content in calvaria then ulna. However mandible showed greater hydroxyproline content and lower glycine content than other spectra. Furthermore, an important finding was the presence of additional amino acids particularly aspartate, leucine and isoleucine in mandible, and glutamate, phenylalanine and methionine in other bone spectra, that might suggests non-collagenous proteins in bone. Additional work is required using new techniques in the NMR that can separate collagenous proteins from the non-collagenous proteins to further explore the complex dynamics of bone
ABSTRACT
The aim of this study was to measure the release of fluoride and strontium ions from bioactive materials known as phosphate glasses in low pH conditions and hence assessing the cariostatic potential of these materials in the oral cavity preventing demineralization of enamel and probably enhancing the process of remineralization of enamel. For this study six bioactive Phosphate glasses of variable compositions containing Phosphate, Calcium, Sodium, Fluoride and Strontium ions were made for this study. Each powder mixture was melted in a platinum crucible at 1150°C and was quenched between stainless-steel plates to produce glasses. The glasses were milled into a powder. Demineralizing solution containing 0.1 M of acetic acid having a pH of 4.0 was prepared. 75 grams of each glass powder was immersed into 50 ml of the demineralization solution and kept in an incubator at 37°C shaking at a constant pace for different time points. After every time point, the solution was checked for precipitates and was filtered out. The filtered solution was sent for Inductively Coupled Plasma Optical Emission Spectroscopy for measurement of Strontium ion release, and Fluoride Ion Selective Electrode for the measurement of Fluoride release 0.17ppm of fluoride was released out of the maximum predicted release of 28 ppm which counts to 1.2% of the total release as measured by the fluoride electrode; along with 7.4 ppm of strontium out of the maximum predicted release of 32 ppm which counts to 23% of the total release as measured by ICP. Maximum release was from glasses incorporated with both strontium and fluoride in the same glass exhibiting synergism