In this chapter, besides its biomedical applications, the synthesis and properties of brushite were investigated. Brushite consists of two types of crystals, platy and needle-like, and their formation depends on the pH of the medium during precipitation. Platy crystals are formed in a slightly acidic medium, pH = 5, and needle-like crystals at a higher pH = 6.5–7. In this study, the monoclinic brushite crystals were synthesized using dissolution-precipitation reactions. It is found that the brushite crystal growth occurs mainly along the (020) crystallographic plane. The thermogravimetric analysis confirms the presence of the two structural water molecules, which decompose at a temperature range between 80 and 220°C. Brushite was used in the preparation of tetracalcium phosphate mineral, which is the powder component for calcium phosphate cement (CPC). CPC was subsequently prepared from TTCP and phosphate-based hardening solution. In vitro evaluation of the resultant CPC using Hanks’ Balanced Salt Solution results in the growth of nanofibrous crystals of Calcium-deficient hydroxyapatite (CDHA) layers on the surfaces of the CPC. The cultured CPC exhibits new connective tissues and throughout the CaP matrix.

The present study investigates the gradual replacement of Ca²⁺ with Mg²⁺ ions in brushite (CaHPO₄·2H₂O). To date, this approach has not been systematically explored and may prove beneficial for the production of Ca_1−xMg_xHPO₄·nH₂O materials with tailored properties which are suitable for environmental and medical applications. For their production, solutions of sodium dihydrogen orthophosphate dehydrate, NaH₂PO₄·2H₂O, calcium nitrate tetrahydrate, Ca(NO₃)₂·4H₂O, magnesium nitrate hexahydrate, Mg(NO₃)₂·6H₂O and ammonium hydroxide solution, NH₄OH, were used. At low Mg/Ca molar ratios (up to 0.25) in the starting solution, partial replacement of Ca with Mg takes place (Mg doping) but no struvite is produced as discrete phase. When the Mg/Ca molar ratio increases gradually to 1.5, in addition to Mg-doped brushite, struvite, NH₄MgPO₄·6H₂O, precipitates. The microstructure of the materials produced for different degrees of Ca replacement with Mg has been analyzed in depth with the use of powdered XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), thermogravimetric (TG) analysis and SEM (scanning electron microscopy). The results of this study prove that the Mg/Ca ratio in the starting solution can be monitored in such a way that materials with tailored composition are obtained.

The gradual replacement of Ca²⁺ with Cu²⁺ ions in brushite (CaHPO₄·2H₂O) has been extensively studied and discussed. The approach adopted in this work has not been systematically explored in previous studies. This novel approach may prove beneficial for the production of Ca_1−xCu_xHPO₄·nH₂O materials with desired properties suitable for medical applications. Solutions of sodium dihydrogen orthophosphate dihydrate, NaH₂PO₄·2H₂O, calcium nitrate tetrahydrate, Ca(NO₃)₂·4H₂O, copper nitrate trihydrate, Cu(NO₃)₂·3H₂O, ammonium hydroxide solution, and diluted HCl were used for the preparation of these materials. At low Cu/Ca molar ratios (up to 0.25) in the starting solution, biphasic phosphate minerals were formed: brushite and sampleite. When the Cu/Ca molar ratio increases gradually from 0.67 to 1.5, sampleite-like mineral precipitates. Powdered XRD (X-ray diffraction), thermogravimetric (TG) analysis, and SEM (scanning electron microscopy) techniques were employed for the study of the microstructure of the produced materials for different degrees of Ca replacement with Mg. It is found that the Cu/Ca ratio in the starting solution can be adjusted to obtain materials with tailored composition. Thus, a new method of sampleite-like synthesis as a rare mineral is introduced in this study. Both phosphate minerals brushite and sampleite-like minerals are attractive as precursors of bioceramics and biocements. The search for such products that may decrease the possibility of post prosthetic or implant infection can be crucial in preventing devastating post-surgical complications.

Because the impact of the full-scale substitution of Ca²⁺ in brushite (CaHPO₄·2H₂O) with Ni²⁺ ions has never been systematically explored, it is the focus of this investigation, as it holds potential for use in Ca_xNi_1−xHPO₄·nH₂O production. These biomaterials have many beneficial characteristics that can be modified to suit diverse applications, including bone tissue regeneration and pharmaceutics. For the present study, NaH₂PO₄·2H₂O, Ca(NO₃)₂·4H₂O, and Ni(NO₃)₂·6H₂O were used in various molar concentrations to obtain the required starting solutions. Previous studies have shown that adding Ni ions in the initial solution below 20% results in the precipitation of monophasic brushite with slight changes in the crystal structure. However, this study confirms that when the Ni ions substitution increases to 20%, a mixture of phases from both brushite and hexaaquanickel(II) hydrogenphosphate monohydrate HNiP (Ni(H₂O)₆·HPO₄·H₂O) is formed. The results confirm that the full replacement (100%) of Ca ions by Ni ions results in a monophasic compound solely comprising orthorhombic HNiP nanocrystals. Therefore, a novel technique of HNiP synthesis using the precipitation method is introduced in this research work. These materials are subsequently analyzed utilizing powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The obtained results confirm that the material microstructure is controlled by the Ni/Ca ratio in the starting solution and can be modified to obtain the desired characteristics of phases and crystals.

This study aimed to explore the effects of the full-scale replacement (up to 100%) of Ca²⁺ ions with Ag¹⁺ ions in the structure of brushite (CaHPO₄·2H₂O). This substitution has potential benefits for producing monophasic and biphasic Ca_1−xAg_xHPO₄·nH₂O compounds. To prepare the starting solutions, (NH₄)₂HPO₄, Ca(NO₃)₂·4H₂O, and AgNO₃ at different concentrations were used. The results showed that when the Ag/Ca molar ratio was below 0.25, partial substitution of Ca with Ag reduced the size of the unit cell of brushite. As the Ag/Ca molar ratio increased to 4, a compound with both monoclinic CaHPO₄·2H₂O and cubic nanostructured Ag₃PO₄ phases formed. There was a nearly linear relationship between the Ag ion ratio in the starting solutions and the wt% precipitation of the Ag₃PO₄ phase in the resulting compound. Moreover, when the Ag/Ca molar ratio exceeded 4, a single-phase Ag₃PO₄ compound formed. Hence, adjusting the Ag/Ca ratio in the starting solution allows the production of biomaterials with customized properties. In summary, this study introduces a novel synthesis method for the mono- and biphasic Ca_1−xAg_xHPO₄·nH₂O compounds brushite and silver phosphate. The preparation of these phases in a one-pot synthesis with controlled phase composition resulted in the enhancement of existing bone cement formulations by allowing better mixing of the starting ingredients.

Purpose: Establishing the normal range of lumbar spinal canal in the Palestinian popula-tion helps provide a quantitative method for assessing spinal canal abnormalities in the lum-bar region. Materials and Methods: The data was gathered from Governmental Hospital in Nablus from January to July 2018. It is a cross-sectional descriptive study among 400 pa-tients (201 males, 199 females), ranging from 20 to 60 years. CT scan radiographs were used to measure the canal and the vertebral body diameters to obtain the canal body ratio. Results: The results represent the normal ratio of dimensions at each level of the bony lumbar spinal canal. The measurements presented are taken at the level of each lumbar vertebra starting from the 1st down to the fifth lumbar vertebra. It was found that the mean ratio of the spinal canal increases from L1 down to L5. Conclusion: After analyzing each lumbar level's results, the mean ratio of the spinal canal increases from L1 to L5. In addition, there were no signifi-cant differences between males and females regarding the measurement tool.