In vivo efficacy of calcium phosphate-based synthetic-bone-mineral on bone loss resulting from estrogen and mineral deficiencies.

Osteopenia and osteoporosis affect over 40 million US adults 50 years and older. Both diseases are strongly influenced by estrogen and nutritional-mineral deficiencies. This study investigates the efficacy of orally delivered synthetic-bone-mineral (SBM), a newly developed calcium phosphate based biomaterial, on reversing bone loss induced by these two critical deficiencies. Thirty 3-month-old female rats were randomly allocated to either control-sham surgery on normal diet; or one of the four experimental groups: Sham surgery on a low mineral diet (LMD), ovariectomized (OVX) on LMD, OVX on LMD with SBM with/without fluoride (F). The rats were sacrificed after 6 months, at 9-month-old. After 6 months, although all groups lost bone mineral density relative to controls, the supplemented OVX rats showed higher bone mineral density than their unsupplemented counterparts. The 2 SBM supplemented groups improved bone loading capacity by 28.1 and 35.4% compared to the OVX LMD group. Bones from supplemented rats exhibited higher inorganic/organic ratios. The addition of F did not have a significant influence on bone loss. Our findings suggest that SBM supplement is effective in maintaining bone health and offsetting the deleterious effects of estrogen and/or mineral deficiencies on bone density, microarchitecture, and strength.

Preservation and promotion of bone formation in the mandible as a response to a novel calcium-phosphate based biomaterial in mineral deficiency induced low bone mass male versus female rats.

Calcium and other trace mineral supplements have previously demonstrated to safely improve bone quality. We hypothesize that our novel calcium-phosphate based biomaterial (SBM) preserves and promotes mandibular bone formation in male and female rats on mineral deficient diet (MD). Sixty Sprague-Dawley rats were randomly assigned to receive one of three diets (n = 10): basic diet (BD), MD or mineral deficient diet with 2% SBM. Rats were sacrificed after 6 months. Micro-computed tomography (µCT) was used to evaluate bone volume and 3D-microarchitecture while microradiography (Faxitron) was used to measure bone mineral density from different sections of the mandible. Results showed that bone quality varied with region, gender and diet. MD reduced bone mineral density (BMD) and volume and increased porosity. SBM preserved BMD and bone mineral content (BMC) in the alveolar bone and condyle in both genders. In the alveolar crest and mandibular body, while preserving more bone in males, SBM also significantly supplemented female bone. Results indicate that mineral deficiency leads to low bone mass in skeletally immature rats, comparatively more in males. Furthermore, SBM administered as a dietary supplement was effective in preventing mandibular bone loss in all subjects. This study suggests that the SBM preparation has potential use in minimizing low peak bone mass induced by mineral deficiency and related bone loss irrespective of gender. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1622-1632, 2016.

Inhibitory effect of Zn2+ in zinc-containing beta-tricalcium phosphate on resorbing activity of mature osteoclasts.

Long term effect of the growing instability of the bone-implant interface due to bone resorption at the interface is a problem for the implants, including bioactive ceramics. Zn2+ -containing tricalcium phosphate (ZnTCP) is a material which may overcome this problem. The present study aims to clarify whether Zn2+ -containing tricalcium phosphate (ZnTCP) ceramics with a Zn2+ content of 0.316 (ZnTCP316) and 0.633 (ZnTCP633) wt % suppress resorption by mature osteoclasts in vitro. Suppression would be due to an increase in the number of apoptotic osteoclasts and the inhibition of the resorbing activity of osteoclasts, the latter being the major mechanism of the suppression. The number of apoptotic osteoclasts was significantly 6.3 times higher with ZnTCP633 than with tricalcium phosphate ceramic (TCP) after 24-h culture. The net contribution to resorption of this change in apoptotic cell numbers is much smaller than that of the change in resorbing activity. The osteoclasts cultured on ZnTCP formed fewer actin rings than those cultured on the TCP. The mRNA expression of CAII and cathepsin K/OC2 in the osteoclasts on ZnTCP633 was downregulated 0.5-fold and 0.6-fold, respectively, compared with that on the TCP. The volume of resorption pits was downregulated 0.4-fold in the ZnTCP633 than that in TCP. These results suggest that ZnTCPs suppressed the resorbing activity of mature osteoclasts probably through a local increase in the level of Zn2+. Bone substitutes or coating layers containing ZnTCP would be promising biomaterials from the viewpoint of counteracting osteoclastic bone resorption at the bone-implant interface.

Black tea extract and dental caries formation in hamsters.

Several studies have suggested that green tea and Oolong tea extracts have antibacterial and anticariogenic properties in vitro and in vivo. The aim of the present study was to determine the effect of a standardized black tea extract (BTE) on caries formation in inbred hamsters on a regular and a cariogenic diet. Eighty hamsters were divided into four groups of 20 animals each. Two groups received a pelleted regular diet (LabChow) with water or BTE ad libitum. The other two groups received a powdered cariogenic diet (Diet 2000, containing 56% sucrose) with water or BTE ad libitum. The animals were kept for 3 months on their respective diets and then were sacrificed. The heads were retained, the jaws were prepared and stained using alizarin mordant red II, and were then scored for dental caries according to the Keyes method. This is the first study indicating that BTE, as compared with water, significantly decreased caries formation by 56.6% in hamsters on a regular diet and by 63.7% in hamsters on a cariogenic diet (P < 0.05). In the cariogenic diet group BTE, reduced the mandibular caries score of the hamsters slightly more than the maxillary caries score. The fluoride content of the standardized BTE solution was frequently monitored during the experiment; the mean fluoride concentration was found to be 4.22 ppm. A frequent intake of black tea can significantly decrease caries formation, even in the presence of sugars in the diet.