Monetite granules were reported to be able to balance osteoclastic resorption and new bone formation. However, to date, the dehydration of preset brushite has been the well-known method for preparing monetite granules. In the present study, for the first time, monetite granules could be prepared from the phase transformation of calcium sulfate dihydrate (CSD) granules through immersion in NaH2PO4 solution under hydrothermal conditions. CSD granules could be fully transformed into monetite granules at a reaction temperature of 125°C for 24 h. The obtained monetite granules were eight times more soluble in acetate buffer than in Tris-HCl buffer. Furthermore, monetite granules were two times more soluble in acetate buffer but comparable in Tris-HCl buffer compared to xenograft HA. The initial cytotoxicity test indicated that the novel monetite granules were nontoxic. In short, novel monetite granules were successfully prepared, exhibited better solubility in osteoclastic simulation than xenograft HA and were nontoxic.

UNASSIGNED: The treatment of osseous bone defects created following enucleation of a cyst is an arduous challenge. Autogenous bone grafts despite being the gold standard have various drawbacks such as donor site morbidity, limited availability of bone graft, and increased operative time. Hence, there are various bone grafts which are being investigated which could overcome the limitations of autografts. Thus, this study was conducted to evaluate the efficacy of calcium sulfate (CS), a bone graft substitute, for spontaneous bone regeneration of cystic defects.
UNASSIGNED: The purpose of this study is to evaluate bone formation in odontogenic cystic defects following enucleation and reconstruction with bone graft substitute by three-dimensional radiographic and clinical evaluation.
UNASSIGNED: A total of twenty patients diagnosed with odontogenic cysts were randomly divided into two groups, out of which the study group had undergone enucleation with bone grafting (tobramycin-impregnated CS dihydrate) and the control group had undergone enucleation without bone grafting. The patients were evaluated clinically and radiographically at the 1st, 3rd, 6th, and 12th months postoperatively.
UNASSIGNED: There was no bone formation observed at 1 month postoperative in both the groups. There was a statistically significant higher bone defect reduction observed radiologically on orthopantomogram and computed tomography scan in the study group than the control group at the 3rd, 6th, and 12th months postoperative. The rate of reduction in cystic volume of the study group at the 12th month was 94.4% and in the control group was 37.16%.
UNASSIGNED: Immediate grafting of cystic cavity can avoid complications such as pathological fracture due to less bone support, delayed healing, etc., The utilization of a graft with a property of inducing rapid bone formation should be taken into consideration. The use of CS as a grafting material accelerated the rate of bone regeneration in the cystic defects, with minimal complications.

Hydroxyapatites of high calcium and phosphate ions adsorption capacity are highly bioactive. However, they cause the removal of these ions from tissue liquids and cell culture media, thus reducing viability and proliferation potential of osteoblasts. Addition of small amount of gypsum (calcium sulfate dihydrate) to such hydroxyapatite-based composites may help to compensate the ions removal and stimulate the osteoblasts growth and proliferation. Therefore, the aim of this work was to enrich the highly porous hydroxyapatite-based composite with gypsum and verify its effect on ions adsorption as well as osteoblasts viability and proliferation. The results showed that addition of 1.5-1.75% gypsum caused short-term calcium ions compensation in media incubated with the composite and time-shifted increase of osteoblasts proliferation. Moreover, presence of gypsum in the composite increased the content of large pores in SBF-incubated biomaterials with no effect on their microstructure or mechanical parameters. Overall, gypsum addition improves the compatibility of hydroxyapatite-based materials with no critical disadvantages for other properties.

In this study, hydroxyapatite (HA)-based microspheres with the ability to deliver bone morphogenetic protein-2 (BMP-2) were developed for accelerating bone regeneration. The incorporation of calcium sulfate dihydrate (CSD) in the HA matrix improved the rate of BMP-2 release from the microspheres. Under physiological conditions, the CSD fully degraded within 7 days and generated pore channels in the microspheres. The porosity and pore size of the HA-CSD microspheres after CSD degradation were 34.3% ± 4.2% and 11.5 ± 2.4 μm, respectively, significantly larger than those of the HA microspheres (23.9% ± 3.1% and 8.7 ± 0.9 μm, respectively). The increased porosity directly affected the rate of BMP-2 release from the microspheres. An in vitro experiment showed that both the BMP-2 release rate and the total amount of BMP-2 released increased considerably when incorporating the HA microspheres with CSD. BMP-2 was released slowly from the HA microspheres for up to 6 weeks. BMP-2 release was notably improved in the HA-CSD biphasic microspheres compared to the microspheres without CSD; the rate of release was 2.4-times faster due to the pores created by CSD dissolution after 7 days. Prior to animal testing, in vitro cell tests were performed to evaluate the biocompatibility of the HA-CSD microspheres. During CSD dissolution, biocompatible bone-like apatite precipitated on the cell surfaces, and preosteoblasts grew on the microspheres. In vivo experiments using a rabbit lateral femoral condyle defect model demonstrated that the level of bone regeneration was significantly enhanced by mineralization on the surface, generated additional pores as well as improved BMP-2 release behavior. The HA-CSD microspheres accelerated new bone growth to fill the entire defect in 6 weeks, corresponding to a 170% improvement in performance compared to the HA microspheres.

Bone cements with the feature of easily shaping could ideally match the defect site and prevent the ingrowth of fibrous tissue. In this manuscript, a biodegradable tricalcium silicate (C3S)/glucono-delta-lactone (GDL)/calcium sulfate dihydrate (CSD) organic-inorganic composite cement was fabricated with shorter setting time (less than 15 min) and high preliminary mechanical property (5.27 MPa in the first hour). Many methods were applied to study the physicochemical and biological properties of the cement in vitro. The weight loss in PBS can reach 58% after 12 weeks soaking indicating the better biodegradability. The excellent bioactivity in vitro was emerging after the cement was soaked in the simulated body fluid. The cell experiments showed that suitable concentration of the extract liquid of cement was conducive to the proliferation, differentiation and extracellular matrix calcification of the mouse bone marrow stromal cells. Briefly, the C3S/GDL/CSD composite cement would have the bright capacity for bone filling.

OBJECTIVE: To analyze the optimum particle size or formula ratio of surgical-grade calcium sulfate (CS) for appropriate compressive strength, setting time, and vitro degradation rate.
METHODS: Three types of calcium sulfate hemihydrate (CSH) particles with diameters of 0-37.5 μm, 37.5-75 μm, and >75 μm were screened. Based on formulation ratio of different particles, this topic is divided into 10 groups by the unconstrained third-order simplex lattice mixing design scheme in formula design experiment. The optimum formulation ratio of particle diameter for compressive strength, solidification time, and degradation rate in vitro was analyzed.
RESULTS: When the percentage of the particle diameter of CS with 0-37.5 μm, 37.5-75 μm and >75 μm are 55.0%, 17.4%, and 27.6% respectively, the compressive strength of the test sample is the highest, which is 14.16 MPa. When the percentage of the particle diameter of CS with 0-37.5 μm, 37.5-75 μm, and >75 μm are 0.00%, 0.00%, and 100.00% respectively, the initial setting time of the sample is the longest, which is 410.0 s. When the percentage of the particle diameter of CS with 0-37.5 μm, 37.5-75 μm, and >75 μm are 0.00%, 0.00%, and 100.00% respectively, the final setting time of the sample is the largest, and the final setting time of the sample is 460.00 s. When the percentage of the particle diameter of CS with 0-37.5 μm, 37.5-75 μm, and >75 μm are 0.00%, 0.00%, and 100.00% respectively, the degradation rate of the sample in vitro is the slowest, which is 18.8%.
CONCLUSIONS: The morphological structure of surgical-grade CS can affect compressive strength, setting time, and in vitro degradation rate. Surgical CS should be prepared based on different uses.

The energetics of cast calcium sulfate dihydrate-aluminum thermites were investigated. The casts were prepared from water slurries with a solids content below 65 wt %. The base case thermite comprised 60 wt % calcium sulfate dihydrate as the oxidizer with 40 wt % aluminum as fuel. The heat of hydration of the base case was 83 ± 4 kJ·kg-1 (dihydrate basis) and the initial setting time was about 100 min. The compressive strength reached 2.9 ± 0.2 MPa after 3 days of drying in ambient air. The open air burn rate was 12.0 ± 1.6 mm· s-1 and a maximum surface temperature of 1370 ± 64 °C was recorded with a pyrometer. Bomb calorimetry indicated an energy output of 8.0 ± 1.1 MJ·kg-1, slightly lower than predicted by the Ekvi thermodynamic simulation. Substitution of 10 wt % of the oxidant with copper sulfate pentahydrate significantly decreased the initial setting time of the casts to less than 30 min but a secondary aluminum oxidation reaction commenced after 2 h. The density of the castings was varied by either adding hollow sodium borosilicate microspheres or by adding excess water during the casting process. The addition of the hollow glass microspheres caused a decrease in the burning rate. Dehydration of the casts by thermal treatments at either 155 or 200 °C led to significant increases in the burning rate.

OBJECTIVE: The aim of the present study was to compare cytotoxicity and migration ability of L929 on medical-grade calcium sulfate dihydrate (MCS) with commercial calcium sulfate dihydrate (CCS).
METHODS: Samples of both freshly-mixed and set states of MCS and CCS were extracted in culture medium and tested for cytotoxicity according to International Organization of Standardization 10993-5:2009. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used, and the percentage of cell viability was calculated. Thirty petri dishes were divided into three equal groups: polystyrene (control), CCS, and MCS. In each petri dish, triplicate wells were made on the agarose overlay on the material. The central well was occupied with L929 cell suspension, one well was filled with platelet-derived growth factor-BB, and the remaining well with Hanks\' Balanced Salt Solution. After incubation, the migration distances were measured and the corrected migration distances were calculated. The final step involved scanning electron microscopy (SEM).
RESULTS: The CCS had significantly less cell viability than MCS at a high extracted concentration (P < 0.001) in both samples. The mean corrected migration of MCS was significantly greater than that of CCS (P < 0.05). SEM showed that L929 cells on MCS exhibited an elongated spindle shape.
CONCLUSIONS: MCS was less cytotoxic and provided greater migration of L929 fibroblasts compared with CCS.