Osteocytes are thought to act as stress sensors, and are known to display a gap junction‐mediated stress‐transfer mechanism. To demonstrate the stress‐related function of osteocytes, cells of an osteocyte‐like cell line derived from murine long bone osteocyte Y4 (MLO‐Y4) were cultivated in a three‐dimensional culture and subjected to cyclic loading from a titanium plate. This application of physiological loading using a titanium plate significantly increased connexin 43 (Cx43) expression, the number of dead and apoptotic cells, and receptor activator of nuclear factor κB ligand expression. Furthermore, the conditioned medium from the loaded osteocytes induced alkaline phosphatase activity in bone marrow cell culture. In addition, we immunohistologically determined whether bone metabolism increased as a result of the occlusal force in the bone surrounding the titanium implants in a rat model. Increased Cx43 expression and apoptotic osteocytes were observed in the loading group as well as a significantly increased number of tartrate‐resistant acid phosphatase‐positive cells. These findings indicate that stress from the implant adversely affected the osteocytes, which may promote osteoclastic and osteoblastic cell formation around the implants. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 815–827, 2019.

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Objective: A dihydropyridine-type calcium channel blocker, benidipine (BD), is extensively used in hypertension therapy. In vitro study reported BD promoting bone metabolism. We evaluated the effect of sustained release of BDloaded poly(lactic-co-glycolic acid) (PLGA) microcarriers on the promotion of bone and gingival healing at an extraction socket in vivo. In addition, the effect of BD on osteoblasts, osteocytes, fibroblasts, and epithelial cells was evaluated in vitro. Approach: The maxillary first molar of rats was extracted. Next, PLGA microcarriers containing BD were directly injected into the gingivobuccal fold as a single dose. After injection, bone and soft-tissue healing was histologically evaluated. Effect of BD on proliferation, migration, and gene expression of gingival and bone cell was also examined in vitro. Results: After tooth extraction, BD significantly augmented bone volume and density, and also epithelial wound healing. During in vitro studies, BD promoted significant proliferation and migration of fibroblasts and epithelial cells. Real-time RT-PCR revealed that BD upregulated messenger RNA expression of Ahsg (alpha 2-HS glycoprotein) and Csf2 (colony-stimulating factor 2) in osteoblasts. Innovation: The prevention of bone and soft-tissue reduction associated with tooth extraction has been eagerly anticipated in the field of dentistry. This study first reported the effect of BD on extraction socket healing. Conclusion: A single dose of topically administered BD-loaded PLGA microcarriers promoted bone and soft-tissue healing at the extraction site of tooth.

The purpose of this study was to evaluate the effect of posterior occlusal support of natural teeth and artificial teeth on oral functions and standing motion. Patients who had been treated with removable prostheses were enrolled as the subjects. Their systemic conditions (body mass index (BMI) and skeletal muscle mass index (SMI)) were recorded. The subjects were classified into two groups according to a modified Eichner index: B1–3 (with posterior occlusal support) and B4C (without posterior occlusal support). Maximum occlusal force (MOF), masticatory performance (MP), and standing motion (sway and strength) were evaluated for cases with and without removable prostheses. There were no significant differences in BMI and SMI between the B1–3 group and the B4C group. The subjects with removable prostheses demonstrated significantly higher values in MOF, MP, and sway and strength than the subjects without removable prostheses. The comparison of oral functions between the B1–3 group and the B4C group revealed that the positive effect of posterior occlusal support of natural teeth and removable prostheses and the significant positive effects of posterior occlusal support on standing motion were partly observed in these comparisons. Posterior occlusal support of natural teeth and even of removable prostheses may contribute to the enhancement of oral functions and standing motion.