Change in bone mineral density and tooth loss in Japanese community-dwelling postmenopausal women: a 5-year cohort study

Oral health indicators and bone mineral density disorders in older age: A systematic review

As we age, maintaining good oral health becomes increasingly crucial for performing daily tasks. Age-related physiological decline can disrupt various biological systems, causing a significant challenge for geriatric dentistry. A systematic review of the literature using six different electronic databases was conducted to investigate the relationship between oral health indicators and bone mineral density disorders in older adults. The study is registered as a priori protocol on PROSPERO (CRD42023403340). A minimum age of 60 years was the main inclusion criterion for all original research articles. Two independent researchers assessed the eligibility of 19,362 records against the inclusion criteria and found 12 articles fitting the eligibility requirements. Five different indicators of poor oral health [number of teeth, periodontal disease, general oral health (dental caries prevalence and dental treatment needs), masticatory function, and occlusal force)] were found related to three outcomes linked to bone mineral density disorders (osteoporosis, fractures, and decreased bone mineral density), regardless of the adopted assessment tools. The number of teeth was negatively associated with fractures and a decreased bone mineral density, while periodontal disease was positively associated with osteoporosis and a decreased bone mineral density. Masticatory function was associated only with osteoporosis, while general oral health was associated only with fractures and occlusal force only with bone mineral density. The oral health indicator most frequently associated with outcomes linked to bone mineral density disorders was the number of teeth. The present findings could help to assess the contribution of each oral health indicator to the development of bone mineral density disorders in older age.

Decreased bone mineral density is associated with an increased number of teeth with periodontitis progression: a 5-year retrospective cohort study

OBJECTIVE

Longitudinal studies on the systemic bone loss-periodontitis relationship are limited with disparate results. The aim of this study was to investigate the association between bone mineral density (BMD) and periodontitis progression, controlling for other covariables in a Thai population.

MATERIALS AND METHODS

In 2,418 participants, BMD values of the lumbar spine, femoral neck, and total hip were measured with dual-energy X-ray absorptiometry at baseline. Each participant's BMD status was classified as normal, osteopenia, or osteoporosis. Full mouth periodontal examinations on 6 sites/tooth were performed at baseline and 5-year follow-up visits. Periodontitis progression was defined as a tooth presenting an additional proximal CAL loss of ≥ 3 mm or an additional lost tooth with a baseline CAL ≥ 5 mm. The risk effects of BMD status on the number of teeth with periodontitis progression were analyzed using multivariate Poisson regression.

RESULTS

Baseline BMD status of osteoporosis was associated with an increased number of teeth with periodontitis progression in the subgroups of postmenopausal women, non-smokers, and participants with periodontitis stage III/IV with adjusted risk ratios of 1.31 (95% CI = 1.09-1.58), 1.19 (95% CI = 1.04-1.36), and 1.13 (95% CI = 1.00-1.28), respectively.

CONCLUSION

Baseline BMD in the osteoporosis range increased the risk of having a greater number of teeth with periodontitis progression in specific participant subgroups.

CLINICAL RELEVANCE

Decreased BMD is a potential factor affecting periodontitis progression risk in some individuals. Multidisciplinary approaches in educating and maintaining patients' bone-oral health may help improve their quality of life.

Increased Risk of Tooth Loss in Postmenopausal Women With Prevalent Vertebral Fractures: An Observational Study

The association between prevalent fractures and tooth loss in postmenopausal women remains unclear. Herein, we investigated the association between prevalent vertebral and nonvertebral fractures, the number of teeth present at baseline, and the number of teeth lost during follow-up in postmenopausal Japanese women. This cross-sectional study enrolled 843 participants (mean age 68.3 years). The number of teeth at follow-up was evaluated in 655 women in this longitudinal study. The participants were divided into four groups according to their prevalent fracture status: no fractures, vertebral fractures alone, nonvertebral fractures alone, and both fracture types. After adjusting for covariates, Poisson regression analyses were performed to investigate differences in the number of teeth at baseline and that lost during the follow-up period among the four groups. Participants with prevalent vertebral fractures alone had significantly fewer teeth at baseline than those in participants without fractures or nonvertebral fractures alone (p < 0.001 for both). Furthermore, they lost more teeth during the follow-up period than did those with no fractures (p = 0.021) and tended to lose more teeth than did those with nonvertebral fractures alone or both prevalent fracture types. We observed no significant difference in the number of teeth lost between the participants with nonvertebral fractures alone and those with no fractures. Postmenopausal women with prevalent vertebral fractures may be at a higher risk of tooth loss. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Relationship between physical activity and bone mineral density loss after gastrectomy in gastric cancer patients

PURPOSE

The prevention of osteoporosis is a particularly relevant issue for gastric cancer survivors. We investigated the relationship between postoperative physical activity and the change of bone mineral density (BMD) in patients with gastric cancer.

METHODS

Patients who underwent radical gastrectomy for gastric cancer were enrolled in this single-center prospective cohort study. Physical activity was evaluated using the International Physical Activity Questionnaire Short Form at postoperative month (POM) 6 and patients were classified into high, middle, and low physical activity groups accordingly. The primary outcome was the change in BMD from baseline at POM 12, which was expressed as a percentage of the young adult mean (YAM). The YAM of the lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry.

RESULTS

One hundred ten patients were enrolled in this study. The physical activity level at POM 6 was classified as high (n = 50; 45%), middle (n = 25; 23%), and low (n = 35; 32%). The mean decrease of YAM% was 5.1% in the lumbar spine and 4.2% in the femoral neck at POM 12. A multivariable-adjusted logistic regression model revealed that low physical activity at POM 6 was a significant risk factor for BMD loss at POM 12 (odds ratio, 3.76; 95% confidence interval, 1.48-9.55; p = 0.005).

CONCLUSION

Low physical activity after gastrectomy is an independent risk factor for decreased BMD at POM 12. The introduction of exercise may prevent osteoporosis after the surgical treatment of gastric cancer.

Association of pentosidine and homocysteine levels with number of teeth present in Japanese postmenopausal women

INTRODUCTION

Little is known about whether substances inducing tissue protein degeneration in the oral cavity are associated with the number of teeth present in postmenopausal women. We sought to investigate the association of urinary pentosidine and serum homocysteine levels with the number of teeth and subsequent tooth loss in Japanese postmenopausal women.

MATERIALS AND METHODS

Among participants in the Nagano Cohort Study, 785 postmenopausal women (mean age, 68.1 years) participated in the present study. The number of teeth was re-counted at the time of follow-up in 610 women. Poisson regression analysis was used to investigate differences in the number of teeth among quartiles of pentosidine or homocysteine, adjusting for covariates that correlated with the number of teeth. A Cox proportional hazard model was used to evaluate the association of subsequent tooth loss with pentosidine or homocysteine levels.

RESULTS

Pentosidine quartiles were not associated with the number of teeth at baseline. Participants in the highest homocysteine quartile had significantly fewer teeth at baseline than those in the third and lowest quartiles (p < 0.001 for both). Those in the second quartile had fewer teeth than those in the third (p = 0.001) and lowest (p < 0.001) quartiles. An increased risk of tooth loss during follow-up was significantly associated with higher urinary pentosidine (hazard ratio = 1.073 for 10 pmol/mgCre; p = 0.001).

CONCLUSION

Postmenopausal women with higher homocysteine levels had fewer teeth at baseline. A higher pentosidine concentration increased the risk of subsequent tooth loss. High pentosidine or homocysteine concentrations may be associated with tooth loss in postmenopausal women.

Transplantation of bone marrow mesenchymal stem cells and fibrin glue into extraction socket in maxilla promoted bone regeneration in osteoporosis rat

AIMS

Bone defect repair in osteoporosis remains a tremendous challenge for clinicians due to increased bone metabolism resulted from estrogen deficiency. This study aims to investigate the effect of bone marrow mesenchymal stem cells (BMSCs) combined with fibrin glue (FG) in the extraction socket healing process of osteoporosis rats, as well as estimate the role of estrogen receptors (ERs) played in BMSCs differentiation in vitro and in the alveolar bone reconstruction process in vivo.

MAIN METHODS

Forty rats were randomly divided into four groups, under general anesthesia, three groups underwent bilateral ovariectomy(OVX) and one group with the sham operation. Three months later, the osteogenic ability of BMSCs, isolated from healthy and osteoporosis rats, respectively, was tested. The ERα and ERβ mRNA expression in BMSCs was also evaluated by RT-PCR analysis. In vivo experiment, Micro-CT detection, histological and immunofluorescent analysis, tissue PCR was conducted up to 2, 4 and 6 weeks after transplantation of BMSCs/FG to assess the newly formed bone in the extraction socket.

KEY FINDINGS

The BMSCs from osteoporosis rats displayed weaker osteogenic potential and lower ERs expression compared with the BMSCs from healthy rats. Newly formed bone tissue filled the socket defect in BMSCs/FG treated VOX rats after six weeks, which was comparable to the sham group, while reduced ERs expression was found in the regenerated bone of the OVX group.

SIGNIFICANCE

The BMSCs seeded within FG might provide an alternative therapeutic method for repairing the extraction socket defect in osteoporosis condition.

Influence of symptomatic periodontal disease on changes in skeletal bone density during medication therapy for osteoporosis in postmenopausal women: the Japanese Osteoporosis Intervention Trial (JOINT)-04 and JOINT-05

Japanese postmenopausal women with symptomatic periodontal disease had a significantly smaller increase in the T-score for total hip bone density than those without periodontal disease during medication therapy for osteoporosis. Intervention to treat symptomatic periodontal disease before and/or during osteoporosis therapy could maintain the effect of osteoporosis medications.

PURPOSE

Women with periodontal disease may be more likely to develop osteoporosis. We evaluated whether the presence of symptomatic periodontal disease can influence changes in skeletal bone mineral density (BMD) during medication therapy for osteoporosis in Japanese postmenopausal women.

METHODS

A total of 4,258 postmenopausal women participated in the Japanese Osteoporosis Intervention Trial protocol number 4 (JOINT-04 trial) and number 5 (JOINT-05 trial), which were multi-center, open-label, randomized controlled trials in Japan. Of these, 3,670 non-edentulous subjects participated in the study. Subjects who had self-reported symptoms of periodontal disease at baseline were defined as having periodontal disease. The study outcome was the difference in BMD changes during the study between subjects with and without periodontal disease. Mixed models for repeated measures after adjusting for covariates were used to investigate the difference in the BMD changes during the study between subjects with and without periodontal disease.

RESULTS

Subjects with periodontal disease had significantly lower T-scores for total hip (p = 0.035) and metacarpal (p = 0.048) BMD than those without periodontal disease at baseline. During medication therapy for osteoporosis, subjects with periodontal disease had a significantly smaller increase in T-score for total hip BMD than those without periodontal disease (p = 0.021), although no significant differences were observed in the changes in T-scores for other skeletal BMD measurements between subjects with and without periodontal disease.

CONCLUSIONS

The presence of self-reported symptoms of periodontal disease may be associated with a decrease in the effect of osteoporosis medications in Japanese postmenopausal women.

Can Male Patient's Age Affect the Cortical Bone Thickness of Jawbone for Dental Implant Placement? A Cohort Study

Dental implants are among the most common treatments for missing teeth. The thickness of the crestal cortical bone at the potential dental implant site is a critical factor affecting the success rate of dental implant surgery. However, previous studies have predominantly focused on female patients, who are at a high risk of osteoporosis, for the discussion of bone quality and quantity at the dental implant site. This study aimed to investigate the effect of male patients’ age on the crestal cortical bone of the jaw at the dental implant site by using dental cone-beam computed tomography (CBCT). This study performed dental CBCT on 84 male patients of various ages to obtain tomograms of 288 dental implant sites at the jawbone (41 sites in the anterior maxilla, 95 in the posterior maxilla, 59 in the anterior mandible, and 93 in the posterior mandible) for measuring the cortical bone thickness. A one-way analysis of variance and Scheffe’s test were performed on the measurement results to compare the cortical bone thickness at implant sites in the four jaw areas. The correlation between male patient age and cortical bone thickness at the dental implant site was determined. The four jaw areas in order of the cortical bone thickness were as follows: posterior mandible (1.07 ± 0.44 mm), anterior mandible (0.99 ± 0.30 mm), anterior maxilla (0.82 ± 0.32 mm), and posterior maxilla (0.71 ± 0.27 mm). Apart from dental implant sites in the anterior and posterior mandibles, no significant correlation was observed between male patients’ age and the cortical bone thickness at the dental implant site.

A 5-year longitudinal association between dietary fermented soya bean (natto) intake and tooth loss through bone mineral density in postmenopausal women: The Yokogoshi cohort study

OBJECTIVE

In this 5-year cohort study, we aimed to determine whether the intake of natto, a fermented soya bean food product, has an indirect effect on tooth loss incidence through BMD changes among postmenopausal women.

BACKGROUND

Evidence indicates (1) that natto has a beneficial effect on bone health and (2) that a decrease in bone mineral density (BMD) is associated with tooth loss.

METHODS

The study recruited 435 postmenopausal women (average age = 64.2 years). Natto intake (exposure) was assessed at baseline using a food frequency questionnaire. Lumbar spine BMD and number of teeth were measured at baseline and 5-year follow-up. BMD change (mediator) and the number of teeth lost (outcome) over time were calculated. The mediation model consisted of these 3 variables. Mediation analysis was performed to test the indirect effect of the natto intake measured through BMD change on tooth loss.

RESULTS

During the study, the mean number of teeth lost was 1.2 (standard deviation = 1.8), and the mean BMD decline was 2.5% (standard deviation = 7.1). After adjusting for potential confounders, increasing habitual natto intake was significantly indirectly associated with a lower incidence of tooth loss mediated by BMD change (incidence rate ratio of tooth loss among women with "≥1 pack/day" natto intake was 0.90 [95% confidence interval = 0.82-0.99] compared to those with natto consumption of "rarely").

CONCLUSIONS

Dietary natto intake is significantly indirectly associated with a lower incidence of tooth loss among postmenopausal women, and systemic bone density could be a mediator of this association.

Association between Age of Menopause and Thickness of Crestal Cortical Bone at Dental Implant Site: A Cross-Sectional Observational Study

Satisfactory host bone quality and quantity promote greater primary stability and better osseointegration, leading to a high success rate in the use of dental implants. However, the increase in life expectancy as a result of medical advancements has led to an aging population, suggesting that osteoporosis may become a problem in clinical dental implant surgery. Notably, relative to the general population, bone insufficiency is more common in women with post-menopausal osteoporosis. The objective of this study was to compare the thickness of the crestal cortical bone at prospective dental implant sites between menopausal and non-menopausal women. Prospective dental implant sites in the jawbone were evaluated in two groups of women: a younger group (<50 years old), with 149 sites in 48 women, and an older group (>50 years old) with 191 sites, in 37 women. The thickness of the crestal cortical bone at the dental implant site was measured based on each patient’s dental cone-beam computed tomography images. For both groups, one-way analysis of variance and Tukey’s post-test were used to assess the correlation between cortical bone thickness and the presence of implants in the four jawbone regions. Student’s t-test was further used to compare differences between the older and younger groups. From the retrospective study results, for both groups, thickness of the crestal cortical bone was the highest in the posterior mandible, followed by anterior mandible, anterior maxilla, and posterior maxilla. Compared with the younger group, the older group had a lower mean thickness of the crestal cortical bone. Among the four regions, however, only in the posterior maxilla was the crestal cortical bone significantly thinner in the older group than in the younger group.

Trabecular bone score, a new bone quality index, is associated with severe periodontitis

BACKGROUND

The association between systemic bone loss and periodontitis remains unresolved; and the trabecular bone score (TBS) is a new index for assessing decreased bone quality. Therefore, this cross-sectional study investigated the association between TBS and severe periodontitis.

METHODS

Eight hundred and five Thai participants, aged 30 to 82 years, underwent bone quality assessment. Their mean TBS was calculated from dual-energy X-ray absorptiometry images at the L1 to L4 lumbar spine using TBS software. Each participant was classified as normal, partially degraded, or degraded TBS. Full-mouth periodontal examinations determined plaque score, probing depth, clinical attachment level (CAL), and the number of remaining teeth. The participants were classified as non-severe or severe periodontitis. Differences in periodontal parameters between the TBS groups were analyzed using one-way ANOVA. The association between TBS and severe periodontitis was assessed with multivariate binary logistic regression. For severe periodontitis, the additive interaction between TBS and oral hygiene status was also analyzed.

RESULTS

The mean CAL was 0.9-mm higher in the degraded TBS group compared with the normal TBS group. Degraded TBS was associated with severe periodontitis with an adjusted odds ratio (OR) of 2.10 (95% confidence interval [CI] = 1.03 to 4.26). The combination of degraded TBS and plaque score ≥80% increased the adjusted OR to 5.71 (95% CI = 1.15 to 28.43).

CONCLUSIONS

Degraded TBS is associated with severe periodontitis and has a synergistic effect with poor oral hygiene, suggesting monitoring decreased bone quality and good oral hygiene for promoting the periodontal-systemic health of these individuals.

Significant association between skeletal bone mineral density and moderate to severe periodontitis in fair oral hygiene individuals

AIM

This cross-sectional study aimed to investigate the association between skeletal bone mineral density (BMD) and periodontitis in Thai adults and elders.

METHODS

This study comprised 3282 participants aged 30-82 years. BMD was assessed at 3 skeletal sites using dual-energy X-ray absorptiometry. Each participant's BMD status was classified as normal, osteopenia or osteoporosis. Periodontal assessments were the number of remaining teeth, plaque score, probing depth and clinical attachment level (CAL). The participants were classified into no/mild or moderate/severe periodontitis groups. The mean periodontal variables between BMD categories were compared. The association between the BMD status and moderate/severe periodontitis was analyzed using binary logistic regression.

RESULTS

Among the BMD categories, the greatest mean CAL and the lowest mean number of remaining teeth were found in the osteoporosis group. The mean CAL difference between the osteoporosis and normal BMD groups was 0.3 mm. In 337 participants with a plaque score of less than 40%, there was a significant association between osteoporosis and moderate/severe periodontitis.

CONCLUSION

Skeletal BMD in the osteoporosis range was associated with moderate/severe periodontitis in individuals with fair oral hygiene, suggesting the benefit of special attention to the skeletal bone health of these individuals.

MAEA rs6815464 polymorphism and periodontitis in postmenopausal Japanese females: A cross-sectional study

OBJECTIVES

Macrophage erythroblast attacher (MAEA) is a membrane protein that regulates the development of mature macrophages by mediating attachment with erythroblasts. A polymorphism rs6815464 (C/G) in MAEA gene was reported to be associated with type II diabetes. Along with diabetes, osteoporosis shows an increased prevalence in postmenopausal females, and both diseases have been reported to be associated with periodontitis. Therefore, we explored the relevance of the MAEA polymorphism to periodontitis, bone mineral density (BMD) and haemoglobin A1c (HbA1c).

DESIGN

This was a cross-sectional study with the final sample comprised of 344 postmenopausal Japanese females. Probing pocket depth (PPD) and clinical attachment level (CAL) were measured. Genotype was determined by TaqMan assay. Blood biochemical parameters and BMD of the lumbar spine were evaluated.

RESULTS

No differences were found in age, body mass index, HbA1c, BMD, number of teeth, bone metabolism parameters between the genotypes. Mean CAL and percentage of sites with PPD or CAL ≥ 5 mm were higher in the G-allele carriers than in the non-carriers. Multiple logistic regression analyses revealed that G-allele carriage was associated with severe periodontitis (odds ratio = 3.73, 95% CI = 1.36-10.19).

CONCLUSION

Our results suggested that the MAEA gene polymorphism was independently associated with severe periodontitis.

Effects of Bone Fragility and Antiresorptive Drugs on Periodontal Disease and Tooth Loss: A Longitudinal Study

This longitudinal study aimed to elucidate whether systemic bone fragility predicts severe periodontal clinical attachment loss (CAL) and tooth loss over the years and to test the influence of bone medication and periodontal maintenance in these relationships. Elderly women were evaluated for bone mineral density (BMD) and for fracture risk assessment (FRAX) in a cross-sectional analysis and retrospective follow-up (6- and 10-y periods). Data on BMD and FRAX were used as indicators of bone fragility in structural equation modeling. Periodontal examination and data on postmenopausal tooth loss were recorded. Multivariate Poisson regression models with robust covariance were used to estimate relative risk (RR) and 95% CI of BMD and FRAX for sites with CAL ≥6 mm and for tooth loss. The cross-sectional analysis included 134 women aged 65 to 80 y, and from them 71 and 49 women had available data for analysis in the 6- and 10-y follow-up periods, respectively. Bone fragility predicted severe CAL over 10 y (e.g., femoral neck: 10-y analysis, β = -0.389, P = 0.005; cross-sectional, β = -0.190, P = 0.004); however, this association did not remain significant when the use of bone medication was evaluated. Poisson regression showed that a better skeletal condition was associated with a lower risk of severe periodontal disease and tooth loss (cross-sectional femoral neck: RR = 0.08, P < 0.001; RR = 0.03, P < 0.001, respectively) when not adjusted for bone medication and periodontal maintenance. The receiver operating characteristic curve suggested that women with osteoporosis should be referred for periodontal assessment (sensitivity = 71.0%, specificity = 70.0%). Bone fragility is a relevant longitudinal predictor of severe periodontal disease and tooth loss among elderly women. The use of bisphosphonates improved the bone condition as well as the periodontal status. Periodontal maintenance also minimized the negative impact of low BMD on teeth-supportive tissues in the studied population. Knowledge Transfer Statement: The results of this study present evidence that the management of bone fragility and osteoporosis may be important in the prevention of periodontal attachment loss and future tooth loss. Besides the antiresorptive effects of the antiosteoporosis drugs on systemic bone conditions, these medications may protect periodontal tissues. The interaction of health care professionals such as dentists and physicians represents a key role for the approach to women's health, especially in an aging world.

Therapeutic effect of localized vibration on alveolar bone of osteoporotic rats

OBJECTIVES

Vibration, in the form of high frequency acceleration (HFA), stimulates alveolar bone formation under physiologic conditions and during healing after dental extractions. It is not known if HFA has an anabolic effect on osteoporotic alveolar bone. Our objective is to determine if HFA has a regenerative effect on osteoporotic alveolar bone.

METHODS AND MATERIALS

Adult female Sprague-Dawley rats were divided into five groups: 1) Ovariectomized Group (OVX), 2) Sham-OVX Group that received surgery without ovariectomy, 3) OVX-HFA Group that was ovariectomized and treated daily with HFA, 4) OVX+Static Force Group that was ovariectomized and received the same force as HFA, but without vibration, and 5) Control Group that did not receive any treatment. All animals were fed a low mineral diet for 3 months. Osteoporosis was confirmed by micro-CT of the fifth lumbar vertebra and femoral head. HFA was applied to the maxillary first molar for 5 minutes/day for 28 and 56 days. Maxillae were collected for micro-CT, histology, fluorescent microscopy, protein and RNA analysis, and three-point bending mechanical testing.

RESULTS

Micro-CT analysis revealed significant alveolar bone osteoporosis in the OVX group. Vibration restored the quality and quantity of alveolar bone to levels similar to the Sham-OVX group. Animals exposed to HFA demonstrated higher osteoblast activity and lower osteoclast activity. Osteogenic transcription factors (RUNX2, Foxo1, Osterix and Wnt signaling factors) were upregulated following vibration, while RANKL/RANK and Sclerostin were downregulated. HFA did not affect serum TRAcP-5b or CTx-1 levels. The osteogenic effect was highest at the point of HFA application and extended along the hemimaxillae this effect did not cross to the contra-lateral side.

CONCLUSIONS

Local application of vibration generated gradients of increased anabolic metabolism and decreased catabolic metabolism in alveolar bone of osteoporotic rats. Our findings suggest that HFA could be a predictable treatment for diminished alveolar bone levels in osteoporosis patients.

FOXO1 Mediates Advanced Glycation End Products Induced Mouse Osteocyte-Like MLO-Y4 Cell Apoptosis and Dysfunctions

Osteocyte plays an essential role in bone metabolism by regulating osteoblast and osteoclast activities. Dysfunction or apoptosis of osteocyte will severely endanger the bone homeostasis and result in bone diseases such as osteoporosis. Osteoporosis has been considered as one of the diabetes complications; however, the mechanism is still to be discovered. Advanced glycation end products (AGEs), as the main pathogenic factor of diabetes mellitus, have the capacity to induce osteocyte apoptosis thus sabotaging bone homeostasis. Here, we examined the role of AGE during osteocyte apoptosis and how this effect would affect osteocyte's regulation of osteoblast and osteoclast. Mouse osteocyte-like MLO-Y4 cells were used to study the properties of osteocyte and to examine its biological and pathological function. MTT assay and Annexin V assay showed that AGE significantly induce MLO-Y4 cell apoptosis. qPCR and Western blot results have shown that AGE upregulates proapoptotic gene p53 and its downstream target gene Bax, which leads to enhanced activation of caspase-3, thus inducing apoptosis in MLO-Y4 cells. Increased expression of sclerostin and RANKL in osteocytes has shown that AGE induces osteocyte dysfunction thus severely damaging the bone homeostasis by decreasing osteoblast and increasing osteoclast activities. Furthermore, the role of the transcription factor FOXO1, which is intensely associated with apoptosis, has been determined. Western blot has shown that AGE significantly decreases Akt activities. Immunofluorescence has shown that AGE promotes FOXO1 nuclei localization and enhances FOXO1 expression. Silencing of FOXO1 suppressed AGE-enhanced apoptosis; mRNA and protein expressions of cleaved caspase-3, sclerostin, and RANKL were downregulated as well. Moreover, exogenous FOXO1 increased caspase-3 mRNA levels and caspase-3 transcriptional activity. Lastly, ChIP assay has established the capacity of FOXO1 binding directly on the caspase-3, sclerostin, and RANKL promoter region in AGE environment, providing the mechanism of the AGE-induced osteocyte apoptosis and dysfunction. Our results have shown that FOXO1 plays a crucial role in AGE-induced osteocyte dysfunction and apoptosis through its regulation of caspase-3, sclerostin, and RANKL. This study provides new insight into diabetes-enhanced risk of osteoporosis given the critical role of AGE in the pathogenesis of diabetes and the essential part of osteocyte in bone metabolism.

Intermittent parathyroid hormone improve bone microarchitecture of the mandible and femoral head in ovariectomized rats

BACKGROUND

Intermittent parathyroid hormone (PTH) can be used to treat osteoporosis of the spine and hip. However, whether it can be used to treat osteoporosis of the mandible is unclear. The purpose of this study was to explore the influence of applying intermittent PTH to ovariectomized rats on the trabecular bone microarchitecture of the mandible and femoral head.

METHODS

Eighteen female rats were divided into three groups: the healthy group, ovariectomized (OVX) group, and OVX + PTH group. The OVX group and OVX + PTH group had an OVX at 8 weeks of age. The OVX + PTH group received intermittent PTH therapy for 12 weeks. The mandibles and femurs of all rats were removed at 20 weeks and were then scanned using microcomputed tomography (micro-CT).

RESULTS

From the micro-CT analysis, the trabecular bone microarchitecture of the mandible and femoral head are offered as follows: (1) The bone volume fraction and trabecular thickness in the OVX group were lower than those in the healthy group. (2) The bone volume fraction and trabecular thickness in the OVX + PTH group approximated those in the healthy group.

CONCLUSION

The conclusions of this study regarding the trabecular bone microarchitecture of the mandible and femoral head are offered as follows: (1) The BV/TV and TbTh in the OVX group were lower than those in the healthy group. (2) The BV/TV and TbTh in the OVX + PTH group approximated those in the healthy group, therefore, intermittent PTH displayed high efficacy for treating femoral or mandibular deterioration of bone microstructure resulting from loss of ovarian function. Osteoporosis of the femur or mandible in the rats was ameliorated by intermittent PTH therapy.

Antiresorptive agent-related osteonecrosis of the jaw in osteoporosis patients from Asian countries

Bisphosphonate (BP)-associated osteonecrosis of the jaw (ONJ) was first reported in oncology patients in 2003 and subsequently in osteoporosis patients in 2004. Since oral surgical procedures, such as tooth extraction, are also considered one of the major risk factors for ONJ, there is confusion among physicians, dentists, and patients—particularly osteoporosis patients currently taking BPs—regarding the safety of remaining on therapy surrounding these procedures. Many papers about BP-related ONJ (BRONJ) have been published to date. In addition to BRONJ, recent studies have reported an association between ONJ and the antiresorptive therapy denosumab (Dmab; a RANKL-inhibitor). BRONJ and Dmab-related ONJ are together referred to as antiresorptive agent-related ONJ (ARONJ). The pathogenesis of ARONJ still remains unknown. It is forecasted that there will be an increased incidence of patients with osteoporotic fractures and an increased number of prescriptions for antiresorptive agents in Asia in the future. However, prescriptions for antiresorptives for osteoporosis may be restricted in the Asian population as the occurrence of ARONJ may be higher as compared with those in other countries. In this review, we focused on the following topics as it pertains to the Asian osteoporotic population: the oral condition specific for osteoporosis patients; definition, staging, prevalence and incidence of ARONJ; imaging modalities for ARONJ; specific risk factors for ARONJ; prevention strategies for ARONJ, and; cooperation between physicians and dentists in the prevention of ARONJ. Ideally, the Asian Federation of Osteoporosis Societies would cooperate with one another and find more population-specific evidence for the prevention of ARONJ.

Association between number of teeth present and mandibular cortical erosion in Japanese men and women aged 40 years and older: A cross-sectional study

Mandibular cortical erosion detected on dental panoramic radiographs is associated with increased risk of osteoporosis in older adults. Additionally, many reports have demonstrated an association between decreased number of teeth present and osteoporosis. However, whether mandibular cortical erosion is associated with a decreased number of teeth remains unclear. The purpose of this study, therefore, was to clarify the association between mandibular cortical erosion and number of teeth present in Japanese men and women aged 40 years and older. Among patients who visited our university hospital and underwent dental panoramic radiography for the diagnosis of dental diseases, 839 patients (293 men and 546 women) aged 40–89 years (mean [SD], 63.7 [10.6] years) participated in this study. Multiple regression analysis revealed that mildly to moderately eroded cortex (p = 0.007) and severe eroded cortex (p < 0.001) were significantly associated with a decreased number of teeth present. Analysis of covariance adjusted for covariates revealed a significant association between mandibular cortical erosion category and number of teeth present (p < 0.001). Subjects with a severely eroded cortex had significantly fewer teeth present than those with a normal cortex (mean [SE], 20.7 [0.5] vs. 23.4 [0.3], p < 0.001) or mildly to moderately eroded cortex (22.2 [0.4], p = 0.04). Subjects with a mildly to moderately eroded cortex had significantly fewer teeth present than those with a normal cortex (p = 0.033). Our results suggest the significant association between mandibular cortical erosion and number of teeth present in Japanese men and women aged 40 years and older.

Metacarpal Cortical Bone Area Predicts Tooth Loss in Men

The relationship between bone mineral density and tooth loss in men is unclear. The aim of this retrospective cohort study was to determine if relative metacarpal bone area (MCA) predicts tooth loss in a cohort of 273 male participants in the Dental Longitudinal Study and Normative Aging Study of the Department of Veterans Affairs. Outer and inner cortical bone widths of the middle metacarpal of the nondominant hand were measured on anteroposterior hand radiographs approximately 11 y apart. Baseline MCA was computed and categorized into quartiles. The men were followed from 1971 to 2015. Incident tooth loss during 2 intervals was examined: concurrent with the MCA measurements and long term over the total follow-up (17 ± 7 y). Radiographic alveolar bone loss (ABL) was measured on periapical radiographs as a percentage of the distance from the cementoenamel junction to root apex, and the number of teeth with ABL >40% was computed. Negative binomial generalized linear regression models estimated the mean number of teeth with ABL >40% and the number lost (concurrent and total), controlling for age, smoking, number of teeth at baseline, percentage teeth with ≥1 decayed/filled surface, and years of follow-up. At baseline, MCA was inversely related to number of teeth with >40% ABL. Men in the lowest MCA quartile (Q1) lost the most teeth, both concurrent with MCA measurements and long term, but the association differed by caries level (≤55% or >55% decayed/filled teeth). At the low caries level, the numbers lost in Q1 were 29% greater than in the highest MCA quartile (Q4). At the high caries level, the numbers lost in Q1 were more than twice those in Q4. Associations were attenuated when further controlled for number of teeth with ABL>40%. These findings suggest that systemic bone status plays a role in tooth loss and that the association may be mediated by alveolar bone loss.

Knowledge Transfer Statement: Low relative metacarpal bone area was related to loss of alveolar bone and incident tooth loss in men. This information extends previous research, primarily studies of women, showing that osteoporosis adversely affects oral health. Knowledge of a patient’s systemic bone status may be important for managing his or her periodontal disease. Tooth loss in the absence of periodontal inflammation may signify systemic bone loss. Interprofessional communication is central to maintaining optimal oral and bone health.

Providing Flaxseed Oil but Not Menhaden Oil Protects against OVX Induced Bone Loss in the Mandible of Sprague-Dawley Rats

Higher intakes of polyunsaturated fatty acids (PUFA) are associated with benefits at several skeletal sites in postmenopausal women and in rodent models, but the effect of PUFA-containing oils on tooth-supporting alveolar bone of the mandible has not been studied. Moreover, direct comparison of the effect of flaxseed oil (a source of alpha-linolenic acid (ALA)) and menhaden oil (a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) is unknown. One-month old female Sprague-Dawley rats (n = 48) were randomized to and fed a diet containing flaxseed oil or menhaden oil from one to six months of age. At three months of age, rats were randomized to receive SHAM or ovariectomy (OVX) surgery (n = 12/diet). The inter-radicular septum below the first molar of the mandible was imaged at 6 months of age (study endpoint) using micro-computed tomography (μCT) at a resolution of 9 μm. As expected, OVX significantly reduced percent bone volume (BV/TV), connectivity density (Conn. D.), trabecular number (Tb. N.), and increased trabecular separation (Tb. Sp.) compared to SHAM rats (p < 0.001). However, post hoc analysis revealed these differences were present in rats fed menhaden oil but not those fed flaxseed oil. These results suggest that providing flaxseed oil, possibly through its high ALA content, provides protection against the OVX-induced alveolar bone loss in rats.

Transplantation of osteoporotic bone marrow stromal cells rejuvenated by the overexpression of SATB2 prevents alveolar bone loss in ovariectomized rats

Estrogen-deficient osteoporosis is an aging-related disease with high morbidity that not only significantly increases a woman's risk of fragility fracture but is also associated with tooth and bone loss in the supporting alveolar bone of the jaw. Emerging evidence suggests that the aging of bone marrow stromal cells (BMSCs) contributes to the development of osteoporosis. In this study, we aimed to investigate the role of the special AT-rich sequence-binding protein 2 (SATB2), a stemness and senescence regulator of craniofacial BMSCs, in rat ovariectomy-induced alveolar osteoporosis. We also sought to determine whether transplantation of SATB2-modified BMSCs could ameliorate estrogen deficient alveolar bone loss. Our data revealed that BMSCs from ovariectomy-induced alveolar bone exhibited typical senescence phenotypes such as diminished stemness and osteogenic capacity, increased expression of senescence or osteoclastic markers and enhanced adipogenic potential. These phenotypic changes are a result of SATB2-mediated senescence dysregulation as evidenced by nuclear γH2AX foci formation. Moreover, overexpression of SATB2 significantly alleviated the senescence of osteoporotic BMSCs in vitro. Importantly, transplantation of SATB2-modified BMSCs significantly attenuated ovariectomy-induced alveolar bone loss in vivo. Together, our results revealed that SATB2 is a critical regulator of alveolar BMSC senescence, and its overexpression decreases these senescent changes both in vitro and in vivo. SATB2-modified BMSC delivery could be a viable and promising therapeutic strategy for alveolar bone loss induced by estrogen-deficient osteoporosis.

Lack of cooperation between physicians and dentists during osteoporosis treatment may increase fractures and osteonecrosis of the jaw

OBJECTIVE

Our previous questionnaire-based survey suggested that discontinuation of antiresorptive agents before tooth extraction may increase adverse events and disturb osteoporosis treatment without completely preventing osteonecrosis of the jaw (O.N.J.). We also found little cooperation between physicians and dentists in Japan. However, limitations of our previous study included a survey of doctors belonging to small clinics and a small sample size. Our current study aimed to confirm the results of our previous survey in doctors mainly belonging to academia.

METHODS

A structured questionnaire including 14 key clinical queries was sent to 1812 physicians of the Japan Osteoporosis Society, and 629 responses were received.

RESULTS

Dentists requested discontinuation of many medications that were not associated with the incidence of O.N.J. A total of 523 respondents had received discontinuation requests from dentists. Of these, 97 respondents experienced 119 adverse events including 25 fractures and seven incidences of O.N.J. The ratios of valid responses for fractures were 3.6% and 5.3% in patients with a discontinuation of <3 and ≥3 months, respectively. Those for O.N.J. were 0.7% and 1.6%, respectively. Respondents who refused discontinuation requests reported no cases of O.N.J. Approximately 17% of respondents had patients who discontinued osteoporosis treatment following a requested drug discontinuation after tooth extraction. Approximately 62% of respondents did not request oral health care by a dentist before antiresorptive therapy, and 72% reported no cooperation between physicians and dentists in their region.

CONCLUSIONS

This study reconfirms the results of our previous survey. Discontinuation of antiresorptive treatment may increase both fractures and O.N.J. Immediate development of a strategy for sharing information about O.N.J. among physicians, dentists, and patients is required to reduce the incidence of both O.N.J. and skeletal events in osteoporosis treatment. Study limitations were selection bias due to low response rate and possible inaccurate responses to the questionnaire.

Cortical Bone Morphological and Trabecular Bone Microarchitectural Changes in the Mandible and Femoral Neck of Ovariectomized Rats

Objective

This study used microcomputed tomography (micro-CT) to evaluate the effects of ovariectomy on the trabecular bone microarchitecture and cortical bone morphology in the femoral neck and mandible of female rats.

Materials and Methods

Twelve female Wister rats were divided into two groups: the control and ovariectomized groups. The rats in the ovariectomized group received ovariectomy at 8 weeks of age; all the rats were sacrificed at 20 weeks of age, and their mandibles and femurs were removed and scanned using micro-CT. Four microstructural trabecular bone parameters were measured for the region below the first mandibular molar and the femoral neck region: bone volume fraction (BV/TV), trabecular thickness (TbTh), trabecular separation (TbSp), and trabecular number (TbN). In addition, four cortical bone parameters were measured for the femoral neck region: total cross-sectional area (TtAr), cortical area (CtAr), cortical bone area fraction (CtAr/TtAr), and cortical thickness (CtTh). The CtTh at the masseteric ridge was used to assess the cortical bone morphology in the mandible. The trabecular bone microarchitecture and cortical bone morphology in the femoral necks and mandibles of the control group were compared with those of the ovariectomized group. Furthermore, Spearman’s correlation (r_s) was conducted to analyze the correlation between the osteoporosis conditions of the mandible and femoral neck.

Results

Regarding the trabecular bone microarchitectural parameters, the BV/TV of the trabecular bone microarchitecture in the femoral necks of the control group (61.199±11.288%, median ± interquartile range) was significantly greater than that of the ovariectomized group (40.329±5.153%). Similarly, the BV/TV of the trabecular bone microarchitecture in the mandibles of the control group (51.704±6.253%) was significantly greater than that of the ovariectomized group (38.486±9.111%). Furthermore, the TbSp of the femoral necks in the ovariectomized group (0.185±0.066 mm) was significantly greater than that in the control group (0.130±0.026mm). Similarly, the TbSp of the mandibles in the ovariectomized group (0.322±0.047mm) was significantly greater than that in the control group (0.285±0.041mm). However, the TbTh and TbN trends for the mandibles and femoral necks were inconsistent between the control and ovariectomized groups. Regarding the cortical bone morphology parameters, the TtAr of the femoral necks in the ovariectomized group was significantly smaller than that in the control group. There was no significant difference in the TtAr, CtAr, or CtTh of the femoral necks between the control and ovariectomized groups, and no significant difference in the CtTh of the mandibles between the control and ovariectomized groups. Moreover, the BV/TV and TbSp of the mandibles were highly correlated with those of the femurs (r_s = 0.874 and r_s = 0.755 for BV/TV and TbSp, respectively). Nevertheless, the TbTh, TbN, and CtTh of the mandibles were not correlated with those of the femoral necks.

Conclusion

After the rats were ovariectomized, osteoporosis of the trabecular bone microarchitecture occurred in their femurs and mandibles; however, ovariectomy did not influence the cortical bone morphology. In addition, the parametric values of the trabecular bone microarchitecture in the femoral necks were highly correlated with those of the trabecular bone microarchitecture in the mandibles.

Oral health behaviors and bone mineral density in South Korea: the 2008-2010 Korean National Health and Nutrition Examination Survey

The purpose of this study was to examine the association between oral health behaviors and bone mineral density (BMD) by using data from the Korean National Health and Nutrition Examination Survey conducted in 2008-2010. We included 6,620 subjects (3,140 men aged more than 50 years and 3,480 postmenopausal women). BMD was measured at three sites-namely, the lumbar spine, total femur, and femur neck. Oral health behaviors were assessed by use of a self-administered questionnaire in the Korean National Health and Nutrition Examination Survey. After adjustment for all covariates, BMD of the lumbar spine and femur neck tended to increase as the frequency of tooth brushing increased in men (p trend = 0.020 and p trend = 0.028, respectively). Women using secondary oral products had increased lumbar spine BMD compared with women who did not use secondary oral products. However, after adjustment for all covariates, no significant relationship was observed between BMD and the use of secondary oral products. As the frequency of tooth brushing and the number of secondary oral products used increased, the prevalence of osteoporosis decreased. The frequency of tooth brushing is associated with increased lumbar spine and femur neck BMD in South Korean men.

The ovariectomized rat as a model for studying alveolar bone loss in postmenopausal women

In postmenopausal women, reduced bone mineral density at the hip and spine is associated with an increased risk of tooth loss, possibly due to a loss of alveolar bone. In turn, having fewer natural teeth may lead to compromised food choices resulting in a poor diet that can contribute to chronic disease risk. The tight link between alveolar bone preservation, tooth retention, better nutritional status, and reduced risk of developing a chronic disease begins with the mitigation of postmenopausal bone loss. The ovariectomized rat, a widely used preclinical model for studying postmenopausal bone loss that mimics deterioration of bone tissue in the hip and spine, can also be used to study mineral and structural changes in alveolar bone to develop drug and/or dietary strategies aimed at tooth retention. This review discusses key findings from studies investigating mandible health and alveolar bone in the ovariectomized rat model. Considerations to maximize the benefits of this model are also included. These include the measurement techniques used, the age at ovariectomy, the duration that a rat is studied after ovariectomy and habitual diet consumed.

Poor Socioeconomic and Nutritional Status Are Associated with Osteoporosis in Korean Postmenopausal Women: Data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES) 2009

OBJECTIVE

As the population ages, osteoporosis is a growing global public health problem. This study examined potential risk factors associated with osteoporosis in a nationally representative sample of Korean postmenopausal women.

METHODS

This study used data from a nationally representative sample of Korean menopausal women participating in the Korea National Health and Nutrition Examination Survey KNHANES 2009 (n = 1467; mean age ± SE = 65.2 ± 0.3 years). Bone mineral density of total femur, femoral neck, and spine was measured by dual-energy X-ray absorptiometry. Osteoporosis was determined as t-score of -2.5 or below in at least 1 of the 3 sites. Menopausal status was confirmed by self-reports.

RESULTS

About 41% of the study sample met the criteria for osteoporosis. Poor socioeconomic status, lower BMI, and shorter estrogen exposure duration were significantly associated with osteoporosis in the study sample. Poor dietary intake was also related to osteoporosis. In the age- and energy-adjusted logistic regression models, participants consuming less protein, vitamin B2, or vitamin C than the estimated average requirement (EAR) showed higher odds of having osteoporosis than their counterparts. Participants consuming no milk or milk products had 45% increased odds of having osteoporosis than those consuming milk or milk products.

CONCLUSION

The findings of this study suggest several risk factors associated with osteoporosis, which can be addressed in the development and implementation of tailored nutritional interventions to promote the bone health of Korean postmenopausal women.

Periodontal health, perceived oral health, and dental care utilization of breast cancer survivors

OBJECTIVES

This population-based analysis examined the prevalence of periodontal diseases along with the self-perceived oral health and patterns of dental care utilization of breast cancer survivors in the United States.

METHODS

Data from the 1999-2004 National Health and Nutrition Surveys were utilized, examining information from 3,354 women between 50 and 85 years of age. Primary outcomes were gingivitis and periodontitis, self-perceived oral health, and dental care utilization. Logistic regression analyses were used to estimate relationships of breast cancer diagnosis and primary outcomes while controlling for confounding factors.

RESULTS

Breast cancer survivors were more likely to be older than 55 years, white, nonsmokers, have higher levels of education and income, and a higher prevalence of osteoporosis. Breast cancer survivors were significantly less likely to have dental insurance (P = 0.04). Utilization of dental services and reason for last dental visit did not significantly differ between groups. A history of a breast cancer diagnosis did not increase the odds of gingivitis [odds ratio (OR):  1.32; 95 percent confidence interval (CI): 0.53-3.63], periodontitis (OR: 1.82; 95 percent CI:  0.89-4.01), or poor self-perceived oral health (OR: 0.89; 95 percent CI: 0.61-1.33) after adjusting for age, race, education, dental care utilization, and smoking status.

CONCLUSIONS

In this sample, a history of breast cancer does not significantly impact periodontal health, self-perceived oral health, and dental care utilization. However, efforts should be made to assure that breast cancer survivors have dental insurance.

Cystatin C-based estimated glomerular filtration rate and periodontitis

BACKGROUND AND OBJECTIVE

Accumulating evidence suggests that decreased kidney function characterised by low estimated glomerular filtration rate (eGFR) may be associated with periodontitis. Recent studies have suggested that the use of cystatin C strengthens the association between the eGFR and the risks of adverse outcomes in decreased kidney function. The aim of this cross-sectional study was to investigate the association of cystatin C-based eGFR (eGFRcys) and creatinine-based eGFR (eGFRcreat), the commonly used method to assess kidney function, with periodontitis in 502 Japanese women (average age, 68.6 years).

MATERIALS AND METHODS

GFR was estimated from serum cystatin C and serum creatinine, respectively, using the Japanese equation for GFR. Participants were classified into five groups according to their eGFRcys and eGFRcreat values. Poisson regression models with robust error variance assessed the associations of eGFRcys and eGFRcreat with periodontitis. Tests for trends were performed by fitting the five-category eGFR variables in their continuous form to the regression models.

RESULTS

Participants with eGFRcys < 50 ml/min/1.73 m(2) were at significantly higher risk of periodontitis compared with the reference group (≥90 ml/min/1.73 m(2) ) (adjusted relative risk = 2.12, 95% confidence interval = 1.12 to 4.02). Additionally, there was a trend towards a higher risk of periodontitis among participants with lower eGFRcys values (p for trend in the multivariable model = 0.008). In contrast, eGFRcreat did not show a significant association with periodontitis.

CONCLUSION

The findings of this study of Japanese older women showed that eGFRcys had a stronger and more linear association with periodontitis than eGFRcreat.

Identification of the risk for osteoporosis in dental patients

This article describes how dentists can recognize osteoporosis before fractures develop, and discusses whether osteoporosis affects tooth loss or inhibits implant osseointegration. Some success in diagnosing osteoporosis has been obtained using clinical questionnaires that attempt to identify those who have strong risk factors for the disease, and analysis of the sparse trabeculation and thinning of the mandibular cortex often seen in dental panoramic radiographs. The role of osteoporosis in periodontal disease is unclear as there are many conflicting reports, but the evidence suggests that tooth loss may be more prevalent in patients with osteoporosis.