It is often assumed that oral hypofunction is associated with social withdrawal in older adults because decreased motor function is related to decreased oral function. However, few studies have examined the relationship between social withdrawal in older adults and oral function. This longitudinal study aimed to clarify the relationship between changes in the level of social withdrawal and oral function in independent older adults. Participants were 427 older adults aged 65 years or older who took part in a self-administered questionnaire from 2016 to 2017 (baseline), and again two years later (follow-up). At baseline, 17 items related to oral function and confounding factors related to withdrawal, physical condition, physical function, and cognitive function were evaluated. A Cox proportional hazard model was used to examine the oral functions that negatively impact social withdrawal. The following factors were significantly associated with the worsening of social withdrawal: the number of remaining teeth, gingival condition, occlusal force, masticatory efficiency, and items related to swallowing and dry mouth. Older adults with cognitive issues who walk slowly and have a weak knee extension muscle were also significantly more likely to have oral frailty. Those who were found to have oral frailty at baseline were 1.8 times more likely to develop withdrawal compared to those with robust oral function. The results indicated that the worsening of withdrawal was associated with oral hypofunction at baseline. Since oral hypofunction was associated with the worsening of social withdrawal in older adults, it is important to maintain older adults’ oral function.

We report a case of a 66-year-old severely osteoporotic woman with bisphosphonate-related osteonecrosis of the jaw (BRONJ) around her dental implants, who was treated successfully with teriparatide and sequestrectomy of the mandible. After 5 months of teriparatide therapy, the sequestrum separation had progressed and a sequestrectomy was performed under general anesthesia. Five months after the operation, new bone formation was observed around the bone defect in the region of the sequestrectomy. A repeat computed tomographic image revealed improvement in the bone defect in the mandible. These results suggest that teriparatide provides beneficial effects in the treatment of advanced BRONJ around dental implants.

BackgroundWe evaluated the side effects of bisphosphonate (BP) on tooth extraction socket healing in spontaneously diabetic Torii (SDT) rats, an established model of non-obese type 2 diabetes mellitus, to develop an animal model of BP-related osteonecrosis of the jaws (BRONJ).Materials and MethodsMale Sprague-Dawley (SD) rats and SDT rats were randomly assigned to the zoledronic acid (ZOL)-treated groups (SD/ZOL or SDT/ZOL) or to the control groups (SD/control or SDT/control). Rats in the SD/ZOL or SDT/ZOL groups received an intravenous bolus injection of ZOL (35 μg/kg) every 2 weeks. Each group consisted of 6 rats each. Twenty-one weeks after ZOL treatment began, the left maxillary molars were extracted. The rats were euthanized at 2, 4, or 8 weeks after tooth extraction, and the total maxillae were harvested for histological and histochemical studies.ResultsIn the oral cavity, bone exposure persisted at the tooth extraction site in all rats of the SDT/ZOL group until 8 weeks after tooth extraction. In contrast, there was no bone exposure in SD/control or SDT/control groups, and only 1 of 6 rats in the SD/ZOL group showed bone exposure. Histologically, necrotic bone areas with empty lacunae, microbial colonies, and less invasion by inflammatory cells were observed. The number of tartrate-resistant acid phosphatase-positive osteoclasts was lower in the SDT/ZOL group than in the SD/control group. The mineral apposition rate was significantly lower in the SDT/ZOL group compared with the SD/control group.ConclusionsThis study demonstrated the development of BRONJ-like lesions in rats and suggested that low bone turnover with less inflammatory cell infiltration plays an important role in the development of BRONJ.

osteoclasts (ocs) differentiate from monocyte/ macrophage-lineage hematopoietic precursor cells, which are known as oc precursors (ocPs). Several studies have investigated cell chemotaxis in the bone microenvironment; however, ocP migration ability in the bone microenvironment during oc differentiation is yet to be elucidated. as an initial investigation of this characteristic, the present study aimed to determine the effects of transforming growth factor (TGF)-β1 on ocP migration in vitro. Pre-osteoclastic raW264.7 cells were cultured with and without TGF-β1 (2, 5 or 20 ng/ml), receptor activator of nF-κB ligand (ranKl; 50 ng/ml), and/or SB431542 (10 µM), a potent and specific inhibitor of TGF-β1 receptor kinase activity. cell proliferation was significantly inhibited in the presence of TGF-β1 for 3 days, and the effect was reversed by SB431542. Tartrate-resistant acid phosphatase (TraP) activity in raW264.7 cells was significantly increased by RANKL treatment, compared with TraP activity in control cells on day 3. The highest TraP activity in raW264.7 cells was induced by the combined treatment with TGF-β1 (2 ng/ml) and ranKl. When TGF-β1 signaling was inhibited by addition of SB431542 to the medium during culture, oc differentiation was notably suppressed. These findings suggest that TGF-β1 accelerates ranKl-induced oc differentiation, but does not act in a dose-dependent manner. The migration of raW264.7 cells was promoted at 24 h, but was suppressed at 72 h, during ranKl-induced osteoclast differentiation in the presence of TGF-β1. These results were accompanied with the increased expression of small G-proteins, rhoa and rac, at 24 h, but their expression decreased at 72 h. raW264.7 cells treated with TGF-β1 for 24 h underwent morphological changes, from round to polygonal morphology. Furthermore, protrusions were completely lost and the cell morphology reverted from polygonal to round after TGF-β1 treatment for 72 h. Therefore, our findings indicated that OCP migration may be modified by differentiation in vitro.

Background Falls among older adults with a low bone density can lead to a bedridden state. Declining bone density increases the risk of falls resulting fractures in older adults. A person’s physical performance is known to be closely related to bone density, and a relationship between the physical performance and the oral function is also known to exist. However, there currently is a lack of evidence regarding the relationship between bone density and the oral function. We assessed the relationship between the bone density and the both the oral function and physical performance among older adults. Patients and methods 754 older adults aged 65 years or older who independently lived in rural regions and who were not taking any medications for osteoporosis participated. We checked all participants for osteoporosis using an ultrasonic bone density measuring device. Regarding the oral function, we evaluated the following factors: remaining teeth, occlusal support, masticatory performance, occlusal force, and tongue pressure. We also evaluated body mass index (BMI) and skeletal muscle mass Index as clinical characteristics. The normal walking speed, knee extension force and one-leg standing test were evaluated as physical performance. For the statistical analyses, we used the Mann–Whitney U test, chi-square test, the Kruskal-Wallis, and a multiple regression analysis. Results Eighty-one percent of the females and 58% of the males had osteoporosis or a decreased bone mass. The occlusal force, masticatory performance and the tongue pressure showed significant association with the bone density. The participants physical performance showed a significant association with their bone states except for walking speed. According to a multiple regression analysis, clinical characteristics (sex, age, BMI), one-leg standing and occlusal force showed independent associations with the bone density. It was suggested that the bone density tends to increase if the occlusal force is high and/or the one-leg standing test results are good. Conclusions The bone density in the older adults showed a significant relationship not only with clinical characteristics or physical performance, but also with occlusal force. It may also be effective to confirm a good oral function in order to maintain healthy living for older adults.