Osteoporosis and Periodontitis

The Relationship Between Alkaline Phosphatase and Periodontitis: The Mediating Role of Cranial Bone Mineral Density

BACKGROUND

Periodontitis is a common chronic disease characterized by the destruction of periodontal tissues and the resorption of alveolar bone, which severely impacts the quality of life of patients. Alkaline phosphatase (ALP), as a crucial marker of bone metabolism, is involved in the bone formation process. However, the mechanisms linking ALP to periodontitis remain unclear. Bone mineral density (BMD) of the skull is an important indicator reflecting bone mineral content and bone strength, yet its mediating role in the relationship between ALP and periodontitis has not been thoroughly investigated.

OBJECTIVE

This study aimed to explore the association between serum ALP and the risk of periodontitis and to evaluate the potential mediating role of cranial BMD in this relationship, with the goal of providing new insights into the etiology of periodontitis and informing treatment strategies.

METHODS

Data from periodontitis patients from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014 were utilized with ALP as the independent variable, periodontitis as the dependent variable, and cranial BMD as the mediating variable. A logistic regression model was used to analyse the relationship between ALP and periodontitis, and subgroup analyses were conducted to explore the association between ALP and periodontitis in different subgroups. Restricted cubic splines (RCS) were used to explore the nonlinear relationship between the two. Additionally, mediation analysis was employed to study the potential mediating role of cranial BMD on the association between ALP and periodontitis.

RESULTS

After adjusting for confounding variables, ALP showed a significant positive association with periodontitis (OR: 1.006, 95% CI: 1.002-1.011, P < .05). Subgroup analyses showed that this association was particularly pronounced in males, drinkers, and individuals lacking physical activities. RCS analysis revealed a nonlinear relationship between ALP and periodontitis (P-non-linear = 0.0006), with a threshold level of 68 U/L. The mediation analysis revealed that cranial BMD played a mediating role of 2.71% in the relationship between ALP and periodontitis (P = .006). Furthermore, ALP was significantly negatively correlated with cranial BMD (β = -0.0016, 95% CI: -0.0024 to -0.0007, P < .001).

CONCLUSION

Elevated serum ALP levels were positively associated with an increased risk of periodontitis, and cranial BMD partially mediated this association. Monitoring ALP levels may contribute to the early diagnosis and intervention of periodontitis, while targeting bone metabolism regulation could offer a novel direction for the treatment of periodontitis.

Exosomes secreted from M2-polarized macrophages inhibit osteoclast differentiation via CYLD

OBJECTIVE

Bone resorption mediated by osteoclast differentiation induces the occurrence of bone-related diseases. Macrophages, an origin of osteoclasts, whose M2 type can reduce inflammation-induced bone damage. We aimed to investigate the effect of M2 macrophage-derived exosomes on osteoclast formation and elucidate its underlying mechanism.

MATERIALS AND METHODS

Exosomes were isolated from M2 macrophages (M2-exo) and were used to treat osteoclast-like cells. Osteoclast formation was evaluated using tartrate-resistant acid phosphatase, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. The molecular mechanism of M2-exo function was analyzed by qRT-PCR, phosphor-kinase array analysis, and Western blotting.

RESULTS

M2-exo was internalized by osteoclasts and inhibited osteoclast differentiation in vitro. Moreover, CYLD was highly expressed in M2 macrophages and M2-exo-treated osteoclasts, and knockdown of it abrogated the inhibition of osteoclast differentiation caused by M2-exo. Additionally, CYLD suppressed the phosphorylation of STAT3, and STAT3 activator colivelin reversed the inhibition of osteoclast differentiation induced by CYLD overexpression.

CONCLUSION

M2-exo inhibits osteoclast differentiation via delivering CYLD, which inactivates STAT3 signaling. These findings may provide a novel therapeutic option for bone diseases including periodontitis.

Increased Prevalence of Periapical Lesions in Osteoporosis Patients: A Systematic Review

Assessing scientific literature about prevalence of periapical lesions in individuals with osteoporosis in comparison to those without osteoporosis. Systematic searches were conducted up to November 24th, 2023 in Cochrane Library, EMBASE, MEDLINE/PubMed, SCOPUS, Web of Science and Grey Literature Reports databases. Only observational studies were included. The ROBINS-E tool, a revised Cochrane instrument for assessing bias in nonrandomized exposure studies, was employed. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was utilized to evaluate the certainty of the evidence. From 484 studies, three were included. One of them was categorized as having an exceptionally high risk of bias, while two were deemed to have certain concerns. Two studies reported that osteoporotic patients may have more chances to present a periapical lesion compared to non-osteoporotic patients. One study reported no differences between groups. The GRADE analysis indicated a markedly low level of certainty in the evidence. The present review indicates that osteoporotic patients may present more periapical lesions compared to non-osteoporotic patients. This statement should be cautiously interpreted and further well-designed studies are needed. (EEJ-2023-09-123).

Association between periodontitis severity and prostate-specific antigen levels using the NHANES data

BACKGROUND

Periodontitis has been linked to various systemic health conditions. This study investigated whether the association between periodontitis and prostate-specific antigen (PSA) is direct or mediated through intermediary systemic diseases.

METHODS

Three data cycles (2001-2002, 2003-2004, and 2009-2010) from the National Health and Nutrition Examination Survey (NHANES) comprising 12,874 subjects were included, and 3020 male participants were analyzed for demographic information, periodontal health indicators, systemic conditions, PSA, and C-reactive protein (CRP) levels. The severity of periodontitis was assessed based on tooth loss, the 2012 Centers for Disease Control and Prevention (CDC)/American Academy of Periodontology (AAP) severity, the 2017 European Federation of Periodontology (EFP)/AAP Workshop stage, and a composite outcome of stage and open pocket percentage. Multilevel stepwise regression analysis examined the association between periodontitis severity (expressed by staging and open pocket percentage) and total PSA levels. Mediation analysis explored potential mediators affecting PSA levels, such as calcium (Ca) levels, osteoporosis, arthritis, and CRP. Logistic regression models were also used to assess the likelihood of elevated PSA levels based on different thresholds (>2 ng/mL, >2.5 ng/mL, >4 ng/mL). Additionally, the data from a complete follow-up survey of 58 patients from the 2003-2004 cycle were included in the analysis.

RESULTS

The study revealed a marginal association between the composite outcome and total PSA levels (p < 0.05). However, logistic regression failed to establish significant associations between periodontitis indicators and elevated PSA levels. Mediation analysis demonstrated that Ca levels, osteoporosis, arthritis, and CRP did not significantly mediate this relationship. The follow-up revealed that edentulous patients were more likely to require additional prostate therapy.

CONCLUSION

There is a marginal association between periodontitis severity and total PSA levels with no significant mediation through factors such as Ca levels, osteoporosis, arthritis, or CRP. Longitudinally, edentulous patients were more likely to require more invasive prostate therapy in the future.

PLAIN LANGUAGE SUMMARY

Periodontitis is an inflammatory condition known to be associated with systemic health. This study aimed to investigate a potential association between periodontitis and prostate cancer, focusing on levels of prostate-specific antigen (PSA), a marker used in prostate cancer screening. Age, race, periodontitis severity, and open pocket percentage were significantly associated with total PSA levels. However, this increase did not significantly correlate with the defined PSA cutoff points of 2, 2.5, and 4. Additionally, calcium levels, osteoporosis, arthritis, and C-reactive protein levels as potential mediators did not significantly impact this relationship. Moreover, edentulous patients were significantly associated with higher odds of needing further treatment for prostate disease. Hence, while considering cases where periodontal disease may contribute to systemic prostate issues, implementing a dual-therapy strategy that addresses both the local inflammation as well as the systemic effects of periodontal disease might be a more effective approach in the management of these conditions.

Radiation Diagnostics of the Maxillofacial Region and Skeleton Bone Density in the Case of Vitamin D Insufficiency: A Pilot Study

(1) Background: A decrease in bone mineral density has been noted not only in at-risk patients (e.g., postmenopausal women) but also in young and middle-aged individuals due to changes in lifestyle. The aim of the study was to find a possible correlation for dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) with cone beam computed tomography (CBCT) of the jaws. (2) Methods: A total of 24 patients (14 women and 10 men aged 25 to 50 years) with partial secondary tooth loss and vitamin D insufficiency underwent cone beam computed tomography of the jaws and skeletal mineral density assessment using DXA (n = 12) and QCT (n = 12). (3) Results: When conducting CBCT of the jaws, a predominance of bone tissue type D3 (350-850 Hu) on the upper jaw (p > 0.05 (F = 0.68) and D2 (850-1350 Hu) on the lower jaw (p > 0.05 (F = 1) was revealed. According to the results of QCT densitometry of the skeleton, signs of osteopenia were found in four patients (with vitamin D3 deficiency) (33%) according to DXA; signs of osteopenia were found in six patients (with severe deficiency and deficiency of vitamin D3) (50%). The difference between QCT and DXA was not significant (p > 0.05) for each group. The significant strong correlation between CBCT and DXA or QCT was not found (p > 0.05). (4) Conclusions: Primary changes in bone density can be detected earlier in the dental system using cone beam computed tomography of the jaws. At the same time, the question of using a specific densitometry method-DXA or QCT-remains open, as their results correlating with CBCT optical density was not approved.

The Impact of Female Hormones on the Periodontium-A Narrative Review

OBJECTIVE

To provide an updated narrative review of current concepts relative to the impact of female hormones on the periodontium throughout the life stages of the female patient. To analyse the implications for the clinician and to amalgamate the main findings from a wide range of empirical studies and theoretical perspectives.

METHOD

Narrative review of the literature synthesising the findings of an extensive collection of literature, published between 2000 and 2024, retrieved from searches of computerised databases, hand searches, authoritative texts and personal communication. Earlier citations outside of the reference range are used to provide historical background to current opinion. The subjects included oestrogen, progesterone, testosterone, puberty, menstruation, contraception, pregnancy, menopause, and periodontal disease, periodontium, inflammation, and the inflammatory cascade.

RESULTS

Drawing from an extensive collection of literature, this review offers insights into the dual function of oestrogen, progesterone, and testosterone in mediating inflammatory and anti-inflammatory responses to local factors, primarily plaque biofilm, and the regulation of the inflammatory cascade. These responses differ between the life stages of puberty, menstruation, contraception, pregnancy, and menopause.

CONCLUSIONS

Key findings demonstrate that hormone fluctuations have a direct and indirect impact on the periodontium, altering the bacterial flora of plaque biofilm to a composition more conducive to the development of periodontal disease and modifying the tissue response to local factors, producing anatomic changes in the gingivae that compromise the periodontium and influencing the regulation of the inflammatory cascade. These factors increase the risk of periodontal disease and susceptibility to other oral conditions associated with female hormone fluctuations.

Estrogen prevented gingival barrier injury from Porphyromonas gingivalis lipopolysaccharide

The postmenopausal population usually suffers from more severe periodontal disease than non-menopausal women due to the decrease and low levels of estrogen, especially β-estradiol (E2). While additional estrogen therapy can effectively relieve alveolar bone resorption, this suggests that estrogen has played an important role in the development of periodontitis. The integrity of the gingival epithelial barrier plays a key role in protecting gingival tissue from inflammatory injury caused by pathogens. However, it remains unclear whether estrogen can maintain the integrity of the gingival epithelial barrier to reduce inflammatory injury. Here, using an infection model established with Porphyromonas gingivalis lipopolysaccharide (LPS) in human gingival epithelial cells (hGECs) and ovariectomized or Sham mice, we assessed the protective effect of estrogen on the gingival barrier using qPCR, western blotting, immunohistochemistry, and transcriptome analysis. The results showed that estrogen restored epithelial barrier function to inhibit P. gingivalis-LPS invasion and further downregulate the inflammatory reaction (P < 0.05) by upregulating expressions of tight junction proteins (such as JAM1 and OCLN) at mRNA and protein levels in both hGECs and ovariectomized or Sham mice (P < 0.05). Estrogen also protected against alveolar bone resorption and preserved barrier integrity in both ovariectomized and Sham mice (P < 0.05). In conclusion, E2 prevented the progression of gingival epithelial barrier damage and inflammation induced by P. gingivalis-LPS by increasing the expression of tight junction proteins. The protective effect of estrogen on gingival epithelial barrier injury highlighted its potential application in treating periodontitis and inflammatory diseases involving epithelial barrier dysfunction.

From teeth to bone: dental caries has causal effects on osteoporosis and osteoporotic fracture

OBJECTIVES

Evidence from observational studies suggested oral diseases (periodontitis (PD) and dental caries) may increase susceptibility to bone loss. However, inherent confounding of observational studies limits causal interpretation. We aimed to conduct Mendelian randomization (MR) analysis to estimate the causal effect of oral diseases on osteoporosis (OP), bone mineral density (BMD) and fracture risk.

METHODS

We used summary-level GWAS meta-analysis data from the GLIDE consortium to identify 7 and 17 single-nucleotide polymorphisms (SNPs) for periodontitis and DMFS (the sum of Decayed, Missing, and Filled tooth Surfaces) as the instrumental variables. MR analyses of these instruments were performed on European individuals for the association with BMD of forearm, femoral neck and lumbar spine; and individuals from FinnGen consortium for OP, OP with pathological fracture, postmenopausal OP with pathological fracture, and site-specific fractures. We performed single-variable Mendelian randomization (SVMR) and multivariable Mendelian randomization (MVMR) to simultaneously assess independent causal effects of PD and DMFS on different outcomes. The estimates were primarily derived using inverse variance weighted (IVW) methods. Sensitivity analyses included weighted median, MR-egger, and Leave-one-out test.

RESULTS

In MVMR, after adjusting for PD, DMFS has a positive causal effect osteoporosis (OR = 1.165, [95% CI 1.020 to 1.331, P = 0.025]) and postmenopausal OP with pathological fracture (OR = 1.422, [95% CI 1.027 to 1.969, P = 0.034]). However, these causal relationships were not observed in the single-variable Mendelian randomization (SVMR) analysis. The causal associations were robust in various sensitivity analyses.

CONCLUSIONS

In conclusion, dental caries causally increases the risk of OP and postmenopausal OP with pathological fracture, suggesting the existence of teeth-bone axis. Proactive osteoporosis screening in patients with severe dental caries may be warranted for clinical consideration.

Grem1 inhibits osteogenic differentiation of MBMSCs in OVX rats through BMP/Smad1/5 signaling pathway

Objective

This study aims to explore how Grem1 regulates the differentiation and signaling activity of mandibular bone marrow mesenchymal stem cells (MBMSCs), affecting their osteogenic differentiation capacity and participating in the pathophysiological mechanism of postmenopausal mandibular osteoporosis.

Materials and methods

A postmenopausal osteoporosis (POP) rat model was constructed via bilateral ovariectomy. Techniques such as Western Blot (WB) and Real-Time Quantitative PCR (RT-qPCR) were employed to determine changes in Grem1 expression in MBMSCs of postmenopausal rats and its effect on osteogenic differentiation. Plasmids for Grem1 overexpression and siRNA for Grem1 knockdown were transfected into MBMSCs, and WB was used to assess the regulatory role of Grem1 on MBMSCs osteogenic differentiation.

Results

Grem1 expression was significantly elevated in the MBMSCs and mandibular tissues of POP rats, accompanied by inhibited osteogenic differentiation. Grem1 levels were inversely proportional to osteogenic capacity and BMP/Smad1/5 signaling activity. BMP-2 alleviated Grem1's inhibitory effects on the BMP/Smad1/5 pathway, influencing MBMSCs' osteogenic differentiation. Upregulating Grem1 in MBMSCs suppressed BMP/Smad1/5 pathway activity and osteogenic differentiation, while Grem1 knockdown restored these processes in the OVX group.

Conclusion

Grem1 reduces osteogenic capacity in mandibular POP rats by inhibiting the BMP/Smad1/5 signaling pathway. Targeting Grem1 or enhancing BMP/Smad1/5 signaling activity may improve mandibular bone health in osteoporosis patients.

Prevalence and associated factors with oral frailty in middle-aged and older hospitalized patients: a cross-sectional study

Background

With the development of the economy and society, people pay more and more attention to oral health. Oral frailty can limit nutritional intake and make an individual physically weak, which is detrimental to people's health. Therefore, it is urgent to identify oral frailty and their associated risk factors. In this study, we aimed to evaluate the oral frailty and its influencing factors in Chinese middle-aged and older hospitalized patients.

Methods

A cross-sectional study was conducted from May 2023 to February 2024 in 2 tertiary hospitals in Wuhu City, Anhui Province, China. The self-designed sociodemographic information, the Oral Frailty Index-8, the 2-item Connor-Davidson resilience scale (CD-RISC-2), the sarcopenia screening questionnaire, and the three-item short literacy survey were used in this study.

Results

A total of 914 middle-aged and older adults patients were recruited. The prevalence of oral frailty was 48.7% (445/914). In the univariate analysis, oral frailty was significantly associated with age, education, place of residence, monthly income, sarcopenia, resilience, and health literacy. Correlation analysis showed that oral frailty was significantly negatively correlated with sarcopenia, resilience, and health literacy. In the binary logistic regression analysis, oral frailty was significantly associated with sarcopenia, and health literacy. Health literacy was a protective factor of oral frailty.

Conclusion

This study aimed to investigate the prevalence of oral frailty and identify the associated influencing factors among middle-aged and older adults patients in Anhui Province, China. This study identified several factors influencing oral frailty in middle-aged and older adults patients. Therefore, the government and relevant departments should implement targeted interventions to improve middle-aged and older adults patients' oral frailty.

Humic Acid Derived from Vermicompost Improves Bone Mineral Content and Alters Oxidative Stress Markers in Ovariectomized Mice

Background: Estrogen depletion alters bone mineralization and oxidative stress. Antioxidants like humic acids (HA) may help mitigate bone demineralization and redox imbalances. Thus, this study evaluated the effects of HA on bone mineral composition and oxidative stress markers in an experimental menopause model. Methods: Twenty-four female C57BL/6 mice were divided into four groups (n = 6/group): Sham; Sham + HA; Ovariectomized (OVX); and OVX + HA. The menopause model was induced by bilateral ovariectomy at the beginning of the experiment. HA derived from biomass vermicompost was administered daily by gavage for 28 days. After euthanasia, femurs and fragments of the gastrocnemius muscle, liver, and kidney were collected. Bone elemental composition was analyzed using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Superoxide dismutase (SOD), catalase (CAT), and hydrogen peroxide (H2O2) activities were assessed in muscle, renal, and hepatic tissues. Data were analyzed using two-way ANOVA and Bonferroni's post hoc test. Results: Untreated OVX mice exhibited a significant reduction in femoral calcium content (p < 0.05). However, HA treatment increased calcium levels and improved the Ca/P ratio (p < 0.05). H2O2 activity was reduced in the liver and kidney of OVX + HA mice compared to untreated animals (p < 0.05). CAT activity in muscle increased in the OVX + HA group compared to the OVX (p < 0.05). Conclusions: HA treatment improved femoral elemental composition and modulated oxidative stress markers in an experimental menopause model.

Ovarian Aging: The Silent Catalyst of Age-Related Disorders in Female Body

Age-related diseases have emerged as a global concern as the population ages. Consequently, understanding the underlying causes of aging and exploring potential anti-aging interventions is imperative. In females, the ovaries serve as the principal organs responsible for ovulation and the production of female hormones. The aging ovaries are related to infertility, menopause, and associated menopausal syndromes, with menopause representing the culmination of ovarian aging. Current evidence indicates that ovarian aging may contribute to dysfunction across multiple organ systems, including, but not limited to, cognitive impairment, osteoporosis, and cardiovascular disease. Nevertheless, due to the widespread distribution of sex hormone receptors throughout the body, ovarian aging affects not only these specific organs but also influences a broader spectrum of age-related diseases in women. Despite this, the impact of ovarian aging on overall age-related diseases has been largely neglected. This review provides a thorough summary of the impact of ovarian aging on age-related diseases, encompassing the nervous, circulatory, locomotor, urinary, digestive, respiratory, and endocrine systems. Additionally, we have outlined prospective therapeutic approaches for addressing both ovarian aging and age-related diseases, with the aim of mitigating their impacts and preserving women's fertility, physical health, and psychological well-being.

Evaluation of mandibular bone structure changes in patients with phenylketonuria through fractal analysis and radiomorphometric indices

OBJECTIVES

The aim of this study was to evaluate the effect of phenylketonuria (PKU) on mandibular bone structure by comparing the bone of PKU patients with healthy controls using fractal analysis (FA) and the radiomorphometric indices of mandibular cortical width (MCW) and mandibular cortical index (MCI).

STUDY DESIGN

In total, 32 patients with PKU were analyzed and compared with the control participants. Regions of interest in panoramic radiographs were selected and the fractal dimension (FD) obtained from FA was calculated. MCW was defined as the cortical thickness of the inferior border of the mandible at the level of the mental foramen. MCI classified the endosteal edge of the mandibular cortex as C1: straight and sharp, C2: the presence lacunar resorption spaces, and C3: distinctly porous and severely eroded. The significance level was P < .05.

RESULTS

All FD and MCW values were significantly lower in the PKU patients. The prevalence of C1 was significantly lower and prevalence of C2 was significantly higher in the PKU group.

CONCLUSIONS

The differences in FD and radiomorphometric indices between patients with PKU and healthy controls may indicate a potential impact of PKU on mandibular bone structure.

Exploring Biomineralization Processes Using In Situ Liquid Transmission Electron Microscopy: A Review

Liquid transmission electron microscopy (TEM) is a newly established technique broadly used to study reactions in situ. Since its emergence, complex and multifaceted biomineralization processes have been revealed with real-time resolution, where classical and non-classical mineralization pathways have been dynamically observed primarily for Ca and Fe-based mineral systems in situ. For years, classical crystallization pathways have dominated theories on biomineralization progression despite observations of non-traditional routes involving precursor phases using traditional- and cryo-TEM. The new dynamic lens provided by liquid TEM is a key correlate to techniques limited to time-stamped, static observations - helping shift paradigms in biomineralization toward non-classical theories with dynamic mechanistic visualization. Liquid TEM provides new insights into fundamental biomineralization processes and essential physiological and pathological processes for a wide range of organisms. This review critically reviews a summary of recent in situ liquid TEM research related to the biomineralization field. Key liquid TEM preparation and imaging parameters are provided as a foundation for researchers while technical challenges are discussed. In future, the expansion of liquid TEM research in the biomineralization field will lead to transformative discoveries, providing complementary dynamic insights into biological systems.

Association of Osteoporosis with Tooth Loss and Dental Radiomorphometric Indices

Background/Objectives: Osteoporosis is a systemic disease associated with reduced bone mass, impaired bone microarchitecture, and thus an increased risk of bone fractures. Moreover, patients with osteoporosis are more likely to experience periodontal diseases and tooth loss. Some indices have been proposed to detect osteoporosis on dental panoramic radiographs. The aim of our retrospective study was to investigate the association between osteoporosis and the loss of alveolar bone and teeth and to evaluate the validity of several dental radiomorphometric indices for assessing osteoporosis. Methods: In patients with and without osteoporosis, tooth loss, alveolar bone loss, the panoramic mandibular index (PMI), mental index (MI), and mandibular cortical index (MCI) were determined. Results: Compared with the non-osteoporotic group, patients with osteoporosis showed more tooth loss and more severe alveolar bone loss. PMI and MI were lower in patients with osteoporosis than in the non-osteoporotic group. Analysis of MCI showed that category C3 (cortical layer forms strong endosteal cortical residues and is clearly porous) was significantly more common in patients with osteoporosis. Conclusions: Osteoporosis is associated with more tooth and alveolar bone loss. Furthermore, various dental radiomorphometric indices are altered in osteoporosis and could thus help to better assess osteoporosis of the jaw.

Epimedium applied in the clinical treatment of osteoporosis patients with periodontitis

Osteoporosis and periodontitis, prevalent in middle-aged and elderly populations, share common features of bone loss and chronic inflammation. This study explores the hypothesis that Epimedium, known for its bone-strengthening properties, may enhance the effectiveness of conventional osteoporosis treatment in patients with coexisting periodontitis. This retrospective study analyzed clinical data from 120 patients with osteoporosis and periodontitis, divided into 2 groups. The control group received calcium carbonate, vitamin D, and zoledronic acid (CC + VD + ZA) therapy, while the observation group received additional Epimedium flavonoid treatment. Outcomes assessed included changes in bone mineral density (BMD), bone metabolism markers (β-CTx, N-MID, CT, ALP), periodontal indices (PD, AL, SBI, PLI), and inflammatory markers in gingival crevicular fluid (GCF) before and 6 months posttreatment. Compared to the control group, the observation group showed significantly greater increases in lumbar spine and proximal femur BMD and reductions in BM markers (P < .05). Periodontal health metrics (PD, AL, SBI, PLI) and GCF inflammatory markers (TNF-α, IL-1β, IL-6, IL-8, hs-CRP, ICAM-1, HMGB1, PGE2) were markedly improved in the observation group, correlating with enhanced total effective rates (TER) for osteoporosis (95.0%) and periodontitis (91.7%) and a reduced adverse event rate (AER). Epimedium shows promise as an adjunctive therapy in patients with osteoporosis and periodontitis, contributing to improved BMD, reduced inflammation, and enhanced periodontal health, suggesting its potential for broader clinical application in managing these coexisting conditions.

Crosstalk between periodontitis and cardiovascular risk

Recent demographic developments resulted in an aged society with a rising disease burden of systemic and non-communicable diseases (NCDs). In cardiovascular disease (CVD), a NCD with high morbidity and mortality, recent preventive strategies include the investigation of comorbidities to reduce its significant economic burden. Periodontal disease, an oral bacterial-induced inflammatory disease of tooth-supporting tissue, is regulated in its prevalence and severity by the individual host response to a dysbiotic oral microbiota. Clinically, both NCDs are highly associated; however, shared risk factors such as smoking, obesity, type II diabetes mellitus and chronic stress represent only an insufficient explanation for the multifaceted interactions of both disease entities. Specifically, the crosstalk between both diseases is not yet fully understood. This review summarizes current knowledge on the clinical association of periodontitis and CVD, and elaborates on how periodontitis-induced pathophysiological mechanisms in patients may contribute to increased cardiovascular risk with focus on atherosclerosis. Clinical implications as well as current and future therapy considerations are discussed. Overall, this review supports novel scientific endeavors aiming at improving the quality of life with a comprehensive and integrated approach to improve well-being of the aging populations worldwide.

The Molecular Comorbidity Network of Periodontal Disease

Periodontal disease, a multifactorial inflammatory condition affecting the supporting structures of the teeth, has been increasingly recognized for its association with various systemic diseases. Understanding the molecular comorbidities of periodontal disease is crucial for elucidating shared pathogenic mechanisms and potential therapeutic targets. In this study, we conducted comprehensive literature and biological database mining by utilizing DisGeNET2R for extracting gene-disease associations, Romin for integrating and modeling molecular interaction networks, and Rentrez R libraries for accessing and retrieving relevant information from NCBI databases. This integrative bioinformatics approach enabled us to systematically identify diseases sharing associated genes, proteins, or molecular pathways with periodontitis. Our analysis revealed significant molecular overlaps between periodontal disease and several systemic conditions, including cardiovascular diseases, diabetes mellitus, rheumatoid arthritis, and inflammatory bowel diseases. Shared molecular mechanisms implicated in the pathogenesis of these diseases and periodontitis encompassed dysregulation of inflammatory mediators, immune response pathways, oxidative stress pathways, and alterations in the extracellular matrix. Furthermore, network analysis unveiled the key hub genes and proteins (such as TNF, IL6, PTGS2, IL10, NOS3, IL1B, VEGFA, BCL2, STAT3, LEP and TP53) that play pivotal roles in the crosstalk between periodontal disease and its comorbidities, offering potential targets for therapeutic intervention. Insights gained from this integrative approach shed light on the intricate interplay between periodontal health and systemic well-being, emphasizing the importance of interdisciplinary collaboration in developing personalized treatment strategies for patients with periodontal disease and associated comorbidities.

Association of tooth loss and periodontal disease with all-cause mortality in cancer survivors: A cohort study based on NHANES

Background

Increasing evidence supports the association between impaired oral health and elevated mortality. However, there is currently a lack of research on the impact of tooth loss and periodontal disease on survival outcomes in cancer survivors. This study aims to clarify the effect of tooth loss and periodontitis on all-cause mortality on cancer survivors.

Methods

The clinical data of cancer survivors were collected from National Health and Nutrition Examination Survey (NHANES) 1999-2018. Mortality data were obtained by linking to records in the National Death Index until December 31, 2019. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal threshold for discriminating mortality based on the number of teeth lost. Kaplan-Meier survival curves and Cox regression analysis were performed to calculate hazard ratios (HRs) and 95 % confidence intervals (95 % CI) for tooth loss and periodontitis.

Results

A total of 3271 cancer survivors were assessed for tooth loss status, while 1267 patients were evaluated for periodontitis status. The prevalence of any tooth loss and CDC-AAP periodontitis was 83.5 % and 47.2 %, respectively. The ROC curve showed the cut-off point of tooth loss for predicting mortality is > 5. Cancer survivors with tooth loss>5 had significantly lower bone density (1.06 vs. 1.13 g/cm2, P < 0.001), elevated C-reactive protein level (0.3 vs. 0.18 mg/dL, P < 0.001), and a trend of lower lean body mass (46.9 vs. 47.6 kg, P = 0.093). Besides, cancer survivors with severe periodontitis also exhibited elevated C-reactive protein level (0.34 vs. 0.21 mg/dL, P = 0.033). All-cause mortality significantly increased in cancer survivors with either tooth loss>5 (HR = 1.290, P = 0.001) or severe CDC-AAP periodontitis (HR = 1.682, P = 0.016) in the multivariate Cox regression analysis.

Conclusion

Tooth loss and periodontitis are strong risk factors for reduced overall survival in cancer survivors. Cancer survivors should emphasize diligent oral hygiene and consistent dental check-ups to optimize long-term oral health. The causal relationship between oral health and survival rates in cancer survivors requires further validation through randomized controlled trials.

Tooth Loss and Systemic Diseases in the Slovenian Elderly Population: A Cross-Sectional Study of the Associaton Between Oral and Systemic Health

Introduction

This study aimed to assess the prevalence of edentulism and tooth loss in the Slovenian elderly population, along with the associated risk factors, and investigate the association between systemic and oral health.

Methods

The study included 445 individuals aged 65 or older (average age: 79.7±8.9 years). Data on preserved teeth, dental history, chronic diseases, and medications were collected through clinical examinations. Height and weight were recorded in order to calculate body mass index (BMI), and the education level was also collected. Chronic systemic diseases and medications were categorized. Statistical analysis was conducted using linear regression and nonparametric tests.

Results

Participants had an average of 4.7±7.7 teeth, with no significant gender differences. Higher age (β=-0.185, p<0.001) and lower education level (p<0.001) were associated with fewer teeth, while higher BMI showed no correlation (β=-0.085, p=0.325). Diabetes mellitus (p=0.031), cardiovascular diseases (p=0.025), and thyroid diseases (p=0.043) were inversely related to retained teeth. This inverse relationship also applied to individuals who recovered from malignancies, not including head and neck malignancies (p=0.019). No significant relationship was found between osteoporosis and the number of teeth (p=0.573). Notably, antidiabetic drug use was inversely related to the number of teeth (p=0.004), while analgesics showed a positive relationship (p=0.022).

Conclusions

This study highlights the association between specific sociodemographic factors, chronic diseases, and retained teeth among elderly individuals in Slovenia. High edentulism rates among the elderly emphasize the need for enhanced preventive measures and risk factor management, particularly for high-risk groups like the elderly.

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.

The Utility of Radiomorphometric Mandibular Indices on Cone Beam Computer Tomography in the Assessment of Bone Mass in Postmenopausal Women: A Cross-Sectional Study

BACKGROUND

The present study examined the potential use of computed tomography radiomorphometric mandibular indices on cone beam CT (CBCT) for the assessment of bone density in postmenopausal women with low bone mass.

METHODS

We included 104 postmenopausal women who received dual-energy X-ray absorptiometry (DXA) using a DXA scanner and mental foramen (MF) region CBCT using a NewTom VGi EVO Cone Beam 3D system. We assessed the relationships between the following DXA parameters: lumbar, femoral neck, and total hip T-scores, bone mineral density (BMD), lumbar trabecular bone score (TBS), and mandibular inferior cortical bone thickness at 4 sites. The cross-sectional images were obtained, as follows: anterior (A)-10 mm anterior from the MF; molar (M)-10 mm posterior from the MF; posterior (P)-25 mm posterior from the MF; symphysis (S)-equidistant from the centers of the right and left MF.

RESULTS

We found that A and M indices showed statistically significant moderate positive correlations with lumbar spine, femoral neck, and total hip BMD, as well as TBS. The P index demonstrated moderate positive correlations with these measurements, while the S index did not show significant correlations with BMD or TBS in postmenopausal women.

CONCLUSIONS

These findings support the potential usefulness of CBCT-derived radiomorphometric mandibular indices for non-invasive bone health assessment in clinical practice.

Jaw osteoporosis: Challenges to oral health and emerging perspectives of treatment

Osteoporosis is a prevalent bone metabolic disease that poses a significant challenge to global human health. Jaw osteoporosis, characterized by microstructural damage of the jaw resulting from various factors, is one of the common manifestations of this condition. Recent studies have demonstrated that jaw osteoporosis has multifaceted effects on oral health and can negatively impact conditions such as periodontitis, oral implantation, orthodontic treatment, and wound healing. However, there are still some limitations in the conventional treatment of osteoporosis. For instance, while bisphosphonates can enhance bone quality, they may also lead to osteonecrosis of the jaw, which poses a potential safety hazard in oral diagnosis and treatment. In recent years, considerable attention has been focused on improving the pathological condition of jaw osteoporosis. Treatment strategies such as gut microbial regulation, extracellular vesicles, molecular targeted therapy, herbal medicine, mechanical stimulation are expected to enhance efficacy and minimize adverse reactions. Therefore, understanding these effects and exploring novel treatments for jaw osteoporosis may provide new insights for oral health maintenance and disease treatment. This article reviews the impact of jaw osteoporosis on oral health and describes the limitations associated with current methods. It also discusses emerging perspectives on treatment, offering a comprehensive overview of the challenges and future directions in managing jaw osteoporosis.

New mechanistic understanding of osteoclast differentiation and bone resorption mediated by P2X7 receptors and PI3K-Akt-GSK3β signaling

OBJECTIVE

Osteoporosis is a global health issue characterized by decreased bone mass and microstructural degradation, leading to an increased risk of fractures. This study aims to explore the molecular mechanism by which P2X7 receptors influence osteoclast formation and bone resorption through the PI3K-Akt-GSK3β signaling pathway.

METHODS

An osteoporosis mouse model was generated through ovariectomy (OVX) in normal C57BL/6 and P2X7f/f; LysM-cre mice. Osteoclasts were isolated for transcriptomic analysis, and differentially expressed genes were selected for functional enrichment analysis. Metabolite analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and multivariate statistical analysis and pattern recognition were used to identify differential lipid metabolism markers and their distribution. Bioinformatics analyses were conducted using the Encyclopedia of Genes and Genomes database and the MetaboAnalyst database to assess potential biomarkers and create a metabolic pathway map. Osteoclast precursor cells were used for in vitro cell experiments, evaluating cell viability and proliferation using the Cell Counting Kit 8 (CCK-8) assay. Osteoclast precursor cells were induced to differentiate into osteoclasts using macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-beta ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) staining was performed to compare differentiation morphology, size, and quantity between different groups. Western blot analysis was used to assess the expression of differentiation markers, fusion gene markers, and bone resorption ability markers in osteoclasts. Immunofluorescence staining was employed to examine the spatial distribution and quantity of osteoclast cell skeletons, P2X7 protein, and cell nuclei, while pit assay was used to evaluate osteoclast bone resorption ability. Finally, in vivo animal experiments, including micro computed tomography (micro-CT), hematoxylin and eosin (HE) staining, TRAP staining, and immunohistochemistry, were conducted to observe bone tissue morphology, osteoclast differentiation, and the phosphorylation level of the PI3K-Akt-GSK3β signaling pathway.

RESULTS

Transcriptomic and metabolomic data collectively reveal that the P2X7 receptor can impact the pathogenesis of osteoporosis through the PI3K-Akt-GSK3β signaling pathway. Subsequent in vitro experiments showed that cells in the Sh-P2X7 + Recilisib group exhibited increased proliferative activity (1.15 versus 0.59), higher absorbance levels (0.68 versus 0.34), and a significant increase in resorption pit area (13.94 versus 3.50). Expression levels of osteoclast differentiation-related proteins MMP-9, CK, and NFATc1 were markedly elevated (MMP-9: 1.72 versus 0.96; CK: 2.54 versus 0.95; NFATc1: 3.05 versus 0.95), along with increased fluorescent intensity of F-actin rings. In contrast, the OE-P2X7 + LY294002 group showed decreased proliferative activity (0.64 versus 1.29), reduced absorbance (0.34 versus 0.82), and a significant decrease in resorption pit area (5.01 versus 14.96), accompanied by weakened expression of MMP-9, CK, and NFATc1 (MMP-9: 1.14 versus 1.79; CK: 1.26 versus 2.75; NFATc1: 1.17 versus 2.90) and decreased F-actin fluorescent intensity. Furthermore, in vivo animal experiments demonstrated that compared with the wild type (WT) + Sham group, mice in the WT + OVX group exhibited significantly increased levels of CTX and NTX in serum (CTX: 587.17 versus 129.33; NTX: 386.00 versus 98.83), a notable decrease in calcium deposition (19.67 versus 53.83), significant reduction in bone density, increased trabecular separation, and lowered bone mineral density (BMD). When compared with the KO + OVX group, mice in the KO + OVX + recilisib group showed a substantial increase in CTX and NTX levels in serum (CTX: 503.50 versus 209.83; NTX: 339.83 versus 127.00), further reduction in calcium deposition (29.67 versus 45.33), as well as decreased bone density, increased trabecular separation, and reduced BMD.

CONCLUSION

P2X7 receptors positively regulate osteoclast formation and bone resorption by activating the PI3K-Akt-GSK3β signaling pathway.

Periodontitis and thyroid function: A bidirectional Mendelian randomization study

BACKGROUND AND OBJECTIVE

Previous studies suggest interaction between periodontitis and thyroid function, while the causality has not yet been established. We applied the Mendelian randomization (MR) method to assess bidirectional causal association between periodontitis and thyroid-related traits, including free thyroxine (FT4), thyroid stimulating hormone (TSH), hypothyroidism, hyperthyroidism and autoimmune thyroid disease (AITD).

METHODS

Genetic instruments were extracted from large-scale genome-wide association studies on normal-range FT4 (N = 49 269) and TSH (N = 54 288) levels, TSH in full range (N = 119 715); hypothyroidism (discovery/replication cohorts: N = 53 423/334 316), hyperthyroidism (discovery/replication cohorts: N = 51 823/257 552), AITD (N = 755 406) and periodontitis (N = 45 563). Here, the inverse variance weighted (IVW) method was applied as the primary analysis, and robustness of results were assessed by several pleiotropic-robust methods. Results were adjusted for Bonferroni correction thresholds with significant p < .004 (0.05/13) and suggestive p between .004 and .05.

RESULTS

The IVW analysis revealed a suggestively causal linkage between genetic predisposition to periodontitis and the increased risk of hypothyroidism (discovery cohort: odds ratio [OR] = 1.24, 95% confidence interval [CI] = 1.05-1.46, p = .012; replication cohort: OR = 1.06, 95% CI = 1.01-1.11, p = .011). No evidence was found for supporting the impact of periodontitis on hyperthyroidism and AITD risks (associated p ≥ .209), as well as thyroid-related traits on periodontitis risk (associated p ≥ .105). These findings were robust and consistent through sensitivity analysis with other MR models.

CONCLUSION

This bidirectional MR reveals periodontitis should not be attributed to variations in thyroid function but it has potential causal effect on hypothyroidism risk, which provides a better understanding of the relationship between periodontitis and thyroid function, and potential evidence for the clinical intervention of hypothyroidism. Further investigations are warranted to elucidate the nature and underlying mechanisms of this finding.

Cationic Glucan Dendrimer Gel-Mediated Local Delivery of Anti-OC-STAMP-siRNA for Treatment of Pathogenic Bone Resorption

Osteoclast stimulatory transmembrane protein (OC-STAMP) plays a pivotal role in the promotion of cell fusion during osteoclast differentiation (osteoclastogenesis) in the context of pathogenic bone resorption. Thus, it is plausible that the suppression of OC-STAMP through a bioengineering approach could lead to the development of an effective treatment for inflammatory bone resorptive diseases with minimum side effects. Here, we synthesized two types of spermine-bearing (Spe) cationic glucan dendrimer (GD) gels (with or without C12) as carriers of short interfering RNA (siRNA) to silence OC-STAMP. The results showed that amphiphilic C12-GD-Spe gel was more efficient in silencing OC-STAMP than GD-Spe gel and that the mixture of anti-OC-STAMP siRNA/C12-GD-Spe significantly downregulated RANKL-induced osteoclastogenesis. Also, local injection of anti-OC-STAMP-siRNA/C12-GD-Spe could attenuate bone resorption induced in a mouse model of periodontitis. These results suggest that OC-STAMP is a promising target for the development of a novel bone regenerative therapy and that C12-GD-Spe gel provides a new nanocarrier platform of gene therapies for osteolytic disease.

Periodontitis and osteoporosis: a two-sample Mendelian randomization analysis

The incidences of periodontitis and osteoporosis are rising worldwide. Observational studies have shown that periodontitis is associated with increased risk of osteoporosis. We performed a Mendelian randomization (MR) study to genetically investigate the causality of periodontitis on osteoporosis. We explored the causal effect of periodontitis on osteoporosis by MR analysis. A total of 9 single nucleotide polymorphisms (SNP) were related to periodontitis. The primary approach in this MR analysis was the inverse variance-weighted (IVW) method. Simple median, weighted median, and penalized weighted median were used to analyze sensitivity. The fixed-effect IVW model and random-effect IVW model showed no significant causal effect of genetically predicted periodontitis on the risk of osteoporosis (OR=1.032; 95%CI: 0.923-1.153; P=0.574; OR=1.032; 95%CI: 0.920-1.158; P=0.588, respectively). Similar results were observed in simple mode (OR=1.031; 95%CI: 0.780-1.361, P=0.835), weighted mode (OR=1.120; 95%CI: 0.944-1.328, P=0.229), simple median (OR=1.003; 95%CI: 0.839-1.197, P=0.977), weighted median (OR=1.078; 95%CI: 0.921-1.262, P=0.346), penalized weight median (OR 1.078; 95%CI: 0.919-1.264, P=0.351), and MR-Egger method (OR=1.360; 95%CI: 0.998-1.853, P=0.092). There was no heterogeneity in the IVW and MR-Egger analyses (Q=7.454, P=0.489 and Q=3.901, P=0.791, respectively). MR-Egger regression revealed no evidence of a pleiotropic influence through genetic variants (intercept: -0.004; P=0.101). The leave-one-out sensitivity analysis indicated no driven influence of any individual SNP on the association between periodontitis and osteoporosis. The Mendelian randomization analysis did not show a significant detrimental effect of periodontitis on the risk of osteoporosis.

The impact of metabolic disorders on management of periodontal health in children

Periodontitis is a chronic inflammatory disease caused by plaque biofilm which shares risk factors with systemic chronic diseases such as diabetes, cardiovascular disease, and osteoporosis. Many studies have found increased prevalence and rate of progression of periodontal disease in children with common metabolic disorders. Although the causal relationship and specific mechanism between them has not been determined yet. The aim of this paper is to progress on the impact of metabolic disorders on periodontal health in children and the underlying mechanisms, which provides new evidences for the prevention and intervention of metabolic disorders and periodontitis in children.

Recent advances in senescence-associated secretory phenotype and osteoporosis

The worldwide elderly population is on the rise, and aging is a major osteoporosis risk factor. Senescent cells accumulation can have a detrimental effect the body as we age. The senescence-associated secretory phenotype (SASP), an essential cellular senescence hallmark, is an important mechanism connecting cellular senescence to osteoporosis. This review describes in detail the characteristics of SASPs and their regulatory agencies, and shed fresh light on how SASPs from different senescent cells contribute to osteoporosis development. Furthermore, we summarized various innovative therapy techniques that target SASPs to lower the burden of osteoporosis in the elderly and discussed the potential challenges of SASPs-based therapy for osteoporosis as a new clinical trial.

Cemental and alveolar bone defects after chronic exposure to amoxicillin in rats (histopathologic and radiographic study)

OBJECTIVES

This study aimed to shed new light on the potential detrimental effects on cementum and adjacent alveolar bone after chronic exposure to amoxicillin.

METHODS

Six pregnant adult Albino rats were equally divided into two groups. Saline solution and amoxicillin (100 mg/Kg) were given to rats of control and amoxicillin group, respectively from the 13th to the 21st day of pregnancy. The same treatment was given to the pups till the 42nd day. The cementum of the first molar teeth and the surrounding alveolar bone were examined qualitatively by histopathological and scanning electron microscope, and quantitatively by energy dispersive X-ray spectroscopy and cone beam computed tomography.

RESULTS

Amoxicillin group depicted cemental and alveolar bone defects along with resorption lacunae. Statistically significant decreases in calcium and calcium/phosphorus ratio in cementum and in calcium only in alveolar bone were evident (p ≤ 0.05). Overall cementum and alveolar bone densities also showed statistically significant decreases (p ≤ 0.05).

CONCLUSION

Chronic amoxicillin administration displayed destructive effects on cementum and the surrounding alveolar bone which may disturb tooth attachment integrity. Therefore, it is recommended to minimize its haphazard usage during pregnancy and early childhood.

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.

Liquid Transmission Electron Microscopy for Probing Collagen Biomineralization

Collagen biomineralization is fundamental to hard tissue assembly. While studied extensively, collagen mineralization processes are not fully understood, with the majority of theories derived from electron microscopy (EM) under static, dehydrated, or frozen conditions, unlike the liquid phase environment where mineralization occurs. Herein, novel liquid transmission EM (TEM) strategies are presented, in which collagen mineralization was explored in liquid for the first time via TEM. Custom thin-film enclosures were employed to visualize the mineralization of reconstituted collagen fibrils in a calcium phosphate and polyaspartic acid solution to promote intrafibrillar mineralization. TEM highlighted that at early time points precursor mineral particles attached to collagen and progressed to crystalline mineral platelets aligned with fibrils at later time points. This aligns with observations from other techniques and validates the liquid TEM approach. This work provides a new liquid imaging approach for exploring collagen biomineralization, advancing toward understanding disease pathogenesis and remineralization strategies for hard tissues.

Osteoprotective Role of the Mir338 Cluster Ablation during Periodontitis

Periodontitis is a chronic inflammatory disease that compromises the integrity of the supporting tissues of the teeth and leads to the loss of the alveolar bone. The Mir338 cluster has been proven to be a potential target for the treatment of osteoporosis and is also enriched in gingival tissues with periodontitis; however, its role in periodontitis remains unknown. Here, we aimed to use periodontitis as a model to expand our understanding of the Mir338 cluster in osteoimmunology and propose a new target to protect against bone loss during periodontitis progression. Significant enrichment of the Mir338 cluster was validated in gingival tissues from patients with chronic periodontitis and a ligature-induced periodontitis mouse model. In vivo, attenuation of alveolar bone loss after 7 d of ligature was observed in the Mir338 cluster knockout (KO) mice. Interestingly, immunofluorescence and RNA sequencing showed that ablation of the Mir338 cluster reduced osteoclast formation and elevated the inflammatory response, with enrichment of IFN-γ and JAK-STAT signaling pathways. Ablation of the Mir338 cluster also skewed macrophages toward the M1 phenotype and inhibited osteoclastogenesis via Stat1 in vitro and in vivo. Furthermore, the local administration of miR-338-3p antagomir prevented alveolar bone loss from periodontitis. In conclusion, the Mir338 cluster balanced M1 macrophage polarization and osteoclastogenesis and could serve as a novel therapeutic target against periodontitis-related alveolar bone loss.

Dental implants in large animal models with experimental systemic diseases: A systematic review

This systematic review aims to identify and discuss the most used methodologies in pre-clinical studies for the evaluation of the implementation of dental implants in systemically compromised pigs and sheep. This study provides support and guidance for future research, as well as for the prevention of unnecessary animal wastage and sacrifice. Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) was used as a guideline; electronic searches were performed in PubMed, Scopus, Scielo, Web of Science, Embase, Science Direct, Brazilian Bibliography of Dentistry, Latin American and Caribbean Literature in Health Sciences, Directory of Open Access Journals, Database of Abstracts of Reviews of Effects, and gray literature until January 2022 (PROSPERO/CRD42021270119). Sixty-eight articles were chosen from the 2439 results. Most studies were conducted in pigs, mainly the Göttinger and Domesticus breeds. Healthy animals with implants installed in the jaws were predominant among the pig studies. Of the studies evaluating the effect of systemic diseases on osseointegration, 42% were performed in osteoporotic sheep, 32% in diabetic sheep, and 26% in diabetic pigs. Osteoporosis was primarily induced by bilateral ovariectomy and mainly assessed by X-ray densitometry. Diabetes was induced predominantly by intravenous streptozotocin and was confirmed by blood glucose analysis. Histological and histomorphometric analyses were the most frequently employed in the evaluation of osseointegration. The animal models presented unique methodologies for each species in the studies that evaluated dental implants in the context of systemic diseases. Understanding the most commonly used techniques will help methodological choices and the performance of future studies in implantology.

Immunometabolic capacities of nutritional fatty acids in regulation of inflammatory bone cell interaction and systemic impact of periodontal infection

Introduction

Novel preventive strategies in periodontal disease target the bacterial-induced inflammatory host response to reduce associated tissue destruction. Strategies focus on the modulation of tissue-destroying inflammatory host response, particularly the reduction of inflammation and promotion of resolution. Thereby, nutrition is a potent immunometabolic non-pharmacological intervention. Human studies have demonstrated the benefit of olive oil-containing Mediterranean-style diets (MDs), the main component of which being mono-unsaturated fatty acid (FA) oleic acid (OA (C18:1)). Hence, nutritional OA strengthened the microarchitecture of alveolar trabecular bone and increased circulating pro-resolving lipid mediators following bacterial inoculation with periodontal pathogen Porphyromonas gingivalis, contrary to saturated FA palmitic acid (PA (C16:0)), which is abundant in Western-style diets. Additionally, the generalized distribution of inflammatory pathway mediators can occur in response to bacterial infection and compromise systemic tissue metabolism and bone homeostasis distant from the side of infection. Whether specific FA-enriched nutrition and periodontal inoculation are factors in systemic pathology that can be immune-modulatory targeted through dietary substitution is unknown and of clinical relevance.

Methods

Normal-weight C57BL/6-mice received OA-or PA-enriched diets (PA-ED, OA-ED, PA/OA-ED) or a normal-standard diet (n=12/group) for 16 weeks and were orally infected with P. gingivalis/placebo to induce periodontal disease. Using histomorphometry and LC-MS/MS, systemic bone morphology, incorporated immunometabolic FA-species, serological markers of bone metabolism, and stress response were determined in addition to bone cell inflammation and interaction in vitro.

Results

In contrast to OA-ED, PA-ED reduced systemic bone microarchitecture paralleled by increased lipotoxic PA-containing metabolite accumulation in bone. Substitution with OA reversed the bone-destructive impact of PA, which was accompanied by reduced diacylglycerols (DAG) and saturated ceramide levels. Further, PA-associated reduction in mineralization activity and concomitant pro-inflammatory activation of primary osteoblasts were diminished in cultures where PA was replaced with OA, which impacted cellular interaction with osteoclasts. Additionally, PA-ED increased osteoclast numbers in femurs in response to oral P. gingivalis infection, whereas OA-ED reduced osteoclast occurrence, which was paralleled by serologically increased levels of the stress-reducing lipokine PI(18:1/18:1).

Conclusion

OA substitution reverses the bone-destructive and pro-inflammatory effects of PA and eliminates incorporated lipotoxic PA metabolites. This supports Mediterranean-style OA-based diets as a preventive intervention to target the accumulation of PA-associated lipotoxic metabolites and thereby supports systemic bone tissue resilience after oral bacterial P. gingivalis infection.

Untreated osteoporosis and higher FRAX as risk factors for tooth loss: a 5-year prospective study

INTRODUCTION

Studies have shown that an impaired bone condition, represented by osteoporosis and increased fracture risk, may potentially aggravate periodontal disease and, consequently, the risk of tooth loss. This 5-year prospective study aimed to investigate whether systemic bone condition represents risk factor for tooth loss due to periodontal disease amongst elderly women.

MATERIAL AND METHODS

Seventy-four participants, aged ≥ 65 years, who attended the 5-years recall for periodontal evaluation were involved. Baseline exposures were osteoporosis and fracture risk probabilities (FRAX). Women were grouped according to bone mineral density (BMD) and years of bone treatment for osteoporosis. The primary outcome at a 5-year follow-up was the number of tooth loss due to periodontal disease. Periodontitis staging and grading, and causes of tooth loss were recorded.

RESULTS

The multivariate Poisson regression models showed that women with untreated/shortly treated osteoporosis were 4 times more likely to present higher number of tooth loss due to periodontal disease than those with normal BMD or treated for ≥ 3 years (risk ratio (RR) = 4.00, 95% CI 1.40-11.27). Higher FRAX was also linked to tooth loss (RR = 1.25, 95% CI 1.02-1.53). Receiver-operating characteristic (ROC) curve suggested that women with history of ≥ 1 tooth losses have higher chances of worse major FRAX (sensitivity = 72.2%; specificity = 72.2%).

CONCLUSION

In this 5-year study, higher FRAX and untreated osteoporosis were risk factors for tooth loss. Women with normal BMD or treated for osteoporosis for ≥ 3 years did not show increased risk. Management of skeletal conditions should be emphasized with periodontal care for the prevention of tooth loss in elderly women.

Heel bone mineral density and various oral diseases: a bidirectional Mendelian randomization

INTRODUCTION

Observational studies demonstrated that the relationship between bone mineral density and oral diseases is mixed. To access the association between heel bone mineral density and various oral diseases, we conducted the Mendelian randomization analysis to explore the association.

MATERIALS AND METHODS

Two-sample bidirectional Mendelian analysis was used to explore the relationship between heel bone mineral density and various oral diseases. The inverse-variance weighted (IVW) was used as the primary effect estimate, and various methods were applied to test the reliability and stability of the results, namely MR-Egger, weighted median, simple mode, and weighted mode.

RESULTS

This study showed that there was a negative relationship between heel BMD and periodontitis when heel BMD was used as an exposure factor and periodontitis as an outcome factor (IVW OR = 0.85; 95% CI, 0.75-0.95; p = 0.005). Bidirectional Mendelian randomization showed that there was no statistically significant association between periodontitis and heel bone mineral density when chronic periodontitis was the exposure factor (p > 0.05). And there was no significant relationship between heel bone mineral density and other oral diseases (dental caries, diseases of pulp and periapical tissues, impacted teeth, cleft lip, and cleft palate, oral and oropharyngeal cancer) (p > 0.05).

CONCLUSION

This study showed that there was a negative relationship between heel bone density and periodontitis, and the decrease in heel bone density could promote the occurrence of periodontitis. In addition, there was no statistically significant relationship between heel bone density and other oral diseases.

Relationship of obstructive sleep apnea with periodontal condition and its local and systemic risk factors

OBJECTIVE

Obstructive sleep apnea (OSA) and periodontitis share risk factors, such as age, obesity, stress, and cardiovascular events, which have a bidirectional cause-effect relationship through systemic inflammation. Our objective was to determine the relationship between OSA and the periodontal condition and its associated local and systemic risk factors.

MATERIAL AND METHODS

This was an observational case-control study involving 60 patients. Local oral risk factors and the systemic condition of each patient were evaluated. All patients underwent polysomnography for the diagnosis of OSA. Chi-squared, one-way ANOVA, and Bonferroni's tests were performed.

RESULTS

A higher percentage of patients with periodontitis had severe OSA (66.66%); however, no statistically significant association was found between the two pathologies (p = 0.290). In terms of systemic risk factors, an association was found between arterial hypertension and severe OSA (p = 0.038), and in terms of local factors, an association was found between the use of removable prostheses and severe OSA (p = 0.0273).

CONCLUSION

In the general population, patients with periodontitis showed a higher prevalence of severe OSA. Obesity and hypothyroidism were the most prevalent systemic findings in patients with OSA and periodontitis. Arterial hypertension and osteoarthritis were found to be associated with severe OSA. The local risk factors associated with periodontitis and severe OSA were removable partial dentures and misfit resins.

CLINICAL RELEVANCE

To study the factors that can facilitate the progression of OSA and periodontitis, physicians and dentists should be advised to provide comprehensive care for patients with both pathologies.

Cementum protein 1 gene-modified adipose-derived mesenchymal stem cell sheets enhance periodontal regeneration in osteoporosis rat

BACKGROUND AND OBJECTIVES

Osteoporosis (OP) and periodontitis are both diseases with excessive bone resorption, and the number of patients who suffer from these diseases is expected to increase. OP has been identified as a risk factor that accelerates the pathological process of periodontitis. Achieving effective and safe periodontal regeneration in OP patients is a meaningful challenge. This study aimed to assess the efficacy and biosecurity of human cementum protein 1 (hCEMP1) gene-modified cell sheets for periodontal fenestration defect regeneration in an OP rat model.

MATERIALS AND METHODS

Rat adipose-derived mesenchymal stem cells (rADSCs) were isolated from Sprague-Dawley rats. After primary culture, rADSCs were subjected to cell surface analysis and multi-differentiation assay. And rADSCs were transduced with hCEMP1 by lentiviral vector, and hCEMP1 gene-modified cell sheets were generated. The expression of hCEMP1 was evaluated by reverse transcription polymerase chain reaction and immunocytochemistry staining, and transduced cell proliferation was evaluated by Cell Counting Kit-8. The hCEMP1 gene-modified cell sheet structure was detected by histological analysis and scanning electron microscopy. Osteogenic and cementogenic-associated gene expression was evaluated by real-time quantitative polymerase chain reaction. In addition, an OP rat periodontal fenestration defect model was used to evaluate the regeneration effect of hCEMP1 gene-modified rADSC sheets. The efficacy was assessed with microcomputed tomography and histology, and the biosecurity of gene-modified cell sheets was evaluated by histological analysis of the spleen, liver, kidney and lung.

RESULTS

The rADSCs showed a phenotype of mesenchymal stem cells and possessed multi-differentiation capacity. The gene and protein expression of hCEMP1 through lentiviral transduction was confirmed, and there was no significant effect on rADSC proliferation. Overexpression of hCEMP1 upregulated osteogenic and cementogenic-related genes such as runt-related transcription factor 2, bone morphogenetic protein 2, secreted phosphoprotein 1 and cementum attachment protein in the gene-modified cell sheets. The fenestration lesions in OP rats treated with hCEMP1 gene-modified cell sheets exhibited complete bone bridging, cementum and periodontal ligament formation. Furthermore, histological sections of the spleen, liver, kidney and lung showed no evident pathological damage.

CONCLUSION

This pilot study demonstrates that hCEMP1 gene-modified rADSC sheets have a marked ability to enhance periodontal regeneration in OP rats. Thus, this approach may represent an effective and safe strategy for periodontal disease patients with OP.

Association between periodontitis and osteoporosis in United States adults from the National Health and Nutrition Examination Survey: a cross-sectional analysis

OBJECTIVE

This cross-sectional study aimed to investigate the association between periodontitis and osteoporosis among US adults as well as the subgroup of menopausal women.

BACKGROUND

Periodontitis and osteoporosis are both chronic inflammatory diseases characterized by local or systemic bone resorption. Since they share many risk factors, and the significant decrease in estrogen along with menopause is unfavorable for both diseases, it's reasonable to assume that there exists some links between the two diseases, especially during the menopause.

METHODS

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2009-2010 and 2013-2014. Periodontitis (defined according to the CDC/AAP definition) and osteoporosis (assessed by the dual-energy radiation absorptiometry) data were available for 5736 participants, and 519 subjects were enrolled in the subgroup of menopausal women aged 45-60 years old. We used binary logistic regression analysis to examine the association between the two diseases both in crude and fully adjusted model.

RESULTS

In the fully adjusted model, osteoporosis was significantly associated with an increased risk of periodontal disease (OR:1.66, 95% CI: 1.00-2.77) in the whole population. As to the subgroup of menopausal women, osteoporosis group had an adjusted OR of 9.66 (95% CI: 1.13-82.38) for developing severe periodontitis in the fully adjusted model.

CONCLUSIONS

Osteoporosis is significantly associated with periodontitis and the association is even more pronounced in menopausal women with severe periodontitis.

BushenHuoxue decoction suppresses M1 macrophage polarization and prevents LPS induced inflammatory bone loss by activating AMPK pathway

Abnormal bone metabolism and subsequence osteoporotic fractures are common complications of chronic inflammatory diseases. No effective treatment for these bone-related complications is available at present. The chronic inflammatory state in these diseases has been considered as a key factor of bone loss. Therefore, the combination of inflammation inhibition and bone loss suppression may be an important strategy for reducing bone damage associated with inflammatory diseases. Bushen Huoxue Decoction (BSHXD) is a traditional Chinese herbal compound that has demonstrated the ability to improve bone quality and increase bone density. However, the efficacy of BSHXD on inflammatory bone loss and its underlying mechanisms remain unclear. This study aimed to investigate whether BSHXD inhibits inflammatory bone loss in mice and its potential molecular mechanisms. In the present study, the effect of BSHXD on lipopolysaccharide (LPS)-induced M1 polarization of RAW264.7 macrophage and on local inflammatory bone loss model of mouse skull was determined. The results showed that after treating RAW264.7 cells with LPS for 24 h, the expression levels of IL-1β (39.42 ± 3.076 ng/L, p < 0.05), IL-6 (49.24 ± 1.766 mg/L, p < 0.05) and TNF-α (286.3 ± 27.12 ng/L, p < 0.05) were significantly increased. The addition of BSHXD decreased the expression levels of IL-1β, IL-6, and TNF-α to 31.55 ± 1.296 ng/L, 37.94 ± 0.8869 mg/L, and 196.4 ± 25.25 ng/L, respectively (p < 0.05). The results of immunofluorescence staining, Western blotting (WB) and flow cytometry indicated that the proportion of M1 macrophages in RAW264.7 cells treated with BSHXD for 24 h was significantly lower than that in the LPS group (13.36% ± 0.9829% VS 24.80% ± 4.619%, p < 0.05). The evidence from in-vitro experiments showed that the immunomodulatory ability of BSHXD may be associated with the activation of AMP-dependent protein kinase (AMPK) pathway in LPS-treated macrophages. In addition, the results of micro-CT, H&E staining, immunohistochemical staining and immunofluorescence staining of mouse skull further demonstrated that BSHXD treatment significantly alleviated LPS-induced local bone loss and inflammatory damage in mouse skull model. All results indicated that BSHXD significantly inhibited inflammatory factors release and M1 polarization of macrophage through AMPK signaling pathway. Therefore, BSHXD may be a promising drug for the treatment of inflammatory bone loss.

Oral frailty indicators to target major adverse health-related outcomes in older age: a systematic review

A well-preserved oral function is key to accomplishing essential daily tasks. However, in geriatric medicine and gerodontology, as age-related physiological decline disrupts several biological systems pathways, achieving this objective may pose a challenge. We aimed to make a systematic review of the existing literature on the relationships between poor oral health indicators contributing to the oral frailty phenotype, defined as an age-related gradual loss of oral function together with a decline in cognitive and physical functions, and a cluster of major adverse health-related outcomes in older age, including mortality, physical frailty, functional disability, quality of life, hospitalization, and falls. Six different electronic databases were consulted by two independent researchers, who found 68 eligible studies published from database inception to September 10, 2022. The risk of bias was evaluated using the National Institutes of Health Quality Assessment Toolkits for Observational Cohort and Cross-Sectional Studies. The study is registered on PROSPERO (CRD42021241075). Eleven different indicators of oral health were found to be related to adverse outcomes, which we grouped into four different categories: oral health status deterioration; decline in oral motor skills; chewing, swallowing, and saliva disorders; and oral pain. Oral health status deterioration, mostly number of teeth, was most frequently associated with all six adverse health-related outcomes, followed by chewing, swallowing, and saliva disorders associated with mortality, physical frailty, functional disability, hospitalization, and falls, then decline in oral motor skills associated with mortality, physical frailty, functional disability, hospitalization, and quality of life, and finally oral pain was associated only with physical frailty. The present findings could help to assess the contribution of each oral health indicator to the development of major adverse health-related outcomes in older age. These have important implications for prevention, given the potential reversibility of all these factors.

Biomimetic Mineralization of Fibrillar Collagen with Strontium-doped Hydroxyapatite

Fibrillar collagen structures mineralized with hydroxyapatite using the polymer-induced liquid precursor (PILP) process have been explored as synthetic models for studying biomineralization of human hard tissues and have also been applied in the fabrication of scaffolds for hard tissue regeneration. Strontium has important biological functions in bone and has been used as a therapeutic agent for treating diseases that result in bone defects, such as osteoporosis. Here, we developed a strategy to mineralize collagen with Sr-doped hydroxyapatite (HA) using the PILP process. Doping with Sr altered the crystal lattice of HA and inhibited the degree of mineralization in a concentration-dependent manner, but did not affect the unique formation of intrafibrillar minerals using the PILP. The Sr-doped HA nanocrystals were aligned in the [001] direction but did not recapitulate the parallel alignment of the c-axis of pure Ca HA in relation to the collagen fiber long axis. The mimicry of doping Sr in PILP-mineralized collagen can help understand the doping of Sr in natural hard tissues and during treatment. The fibrillary mineralized collagen with Sr-doped HA will be explored in future work as biomimetic and bioactive scaffolds for regeneration of bone and tooth dentin.

Overview on postmenopausal osteoporosis and periodontitis: The therapeutic potential of phytoestrogens against alveolar bone loss

Osteoporosis and periodontitis are two major chronic diseases of postmenopausal women. The association between these two diseases are evident through systemic bone loss and alveolar bone loss. Both postmenopausal osteoporosis and periodontitis impose a considerable personal and socioeconomic burden. Biphosphonate and hormone replacement therapy are effective in preventing bone loss in postmenopausal osteoporosis and periodontitis, but they are coupled with severe adverse effects. Phytoestrogens are plant-based estrogen-like compounds, which have been used for the treatment of menopause-related symptoms. In the last decades, numerous preclinical and clinical studies have been carried out to evaluate the therapeutic effects of phytoestrogens including bone health. The aim of this article is to give an overview of the bidirectional interrelationship between postmenopausal osteoporosis and periodontitis, summarize the skeletal effects of phytoestrogens and report the most studied phytoestrogens with promising alveolar bone protective effect in postmenopausal osteoporosis model, with and without experimental periodontitis. To date, there are limited studies on the effects of phytoestrogens on alveolar bone in postmenopausal osteoporosis. Phytoestrogens may have exerted their bone protective effect by inhibiting bone resorption and enhancing bone formation. With the reported findings on the protective effects of phytoestrogens on bone, well-designed trials are needed to better investigate their therapeutic effects. The compilation of outcomes presented in this review may provide an overview of the recent research findings in this field and direct further in vivo and clinical studies in the future.

The association between sex hormones and periodontitis among American adults: A cross-sectional study

Introduction

After adulthood, as a person grows older, the secretion of sex hormones in the body gradually decreases, and the risk of periodontitis increases. But the relationship between sex hormones and periodontitis is still controversial.

Methods

We investigated the association between sex hormones and periodontitis among Americans over 30 years old. 4,877 participants containing 3,222 males and 1,655 postmenopausal females who had had periodontal examination and detailed available sex hormone levels, were included in our analysis from the 2009-2014 National Health and Nutrition Examination Surveys cycles. We applied multivariate linear regression models to estimate the connection between sex hormones and periodontitis after converting sex hormones into categorical variables through tertile. Additionally, to ensure the stability of the analysis results, we carried out a trend test, subgroup analysis, and interaction test.

Results

After fully adjusting the covariates, estradiol levels were not associated with periodontitis in both males and females with a P for trend = 0.064 and 0.064, respectively. For males, we found that sex hormone-binding globulin was positively associated with periodontitis (tertile3 vs tertile1: OR=1.63, 95% CI=1.17-2.28, p = 0.004, P for trend = 0.005). Congruously, free testosterone (tertile3 vs tertile1: OR=0.60, 95% CI=0.43-0.84, p = 0.003), bioavailable testosterone (tertile3 vs tertile1: OR=0.51, 95% CI=0.36-0.71, p < 0.001), and free androgen index (tertile3 vs tertile1: OR=0.53, 95% CI=0.37-0.75, p < 0.001) was found to be negatively associated with periodontitis. Moreover, subgroup analysis of age found a closer relationship between sex hormones and periodontitis in those younger than 50 years.

Conclusion

Our research suggested that males with lower bioavailable testosterone levels affected by sex hormone-binding globulin were at a higher risk of periodontitis. Meanwhile, estradiol levels were not associated with periodontitis in postmenopausal women.

Electroactive Biomaterials for Facilitating Bone Defect Repair under Pathological Conditions

Bone degeneration associated with various diseases is increasing due to rapid aging, sedentary lifestyles, and unhealthy diets. Living bone tissue has bioelectric properties critical to bone remodeling, and bone degeneration under various pathological conditions results in significant changes to these bioelectric properties. There is growing interest in utilizing biomimetic electroactive biomaterials that recapitulate the natural electrophysiological microenvironment of healthy bone tissue to promote bone repair. This review first summarizes the etiology of degenerative bone conditions associated with various diseases such as type II diabetes, osteoporosis, periodontitis, osteoarthritis, rheumatoid arthritis, osteomyelitis, and metastatic osteolysis. Next, the diverse array of natural and synthetic electroactive biomaterials with therapeutic potential are discussed. Putative mechanistic pathways by which electroactive biomaterials can mitigate bone degeneration are critically examined, including the enhancement of osteogenesis and angiogenesis, suppression of inflammation and osteoclastogenesis, as well as their anti-bacterial effects. Finally, the limited research on utilization of electroactive biomaterials in the treatment of bone degeneration associated with the aforementioned diseases are examined. Previous studies have mostly focused on using electroactive biomaterials to treat bone traumatic injuries. It is hoped that this review will encourage more research efforts on the use of electroactive biomaterials for treating degenerative bone conditions.

Mechanisms of estrogen deficiency-induced osteoporosis based on transcriptome and DNA methylation

Osteoporosis is a disease that impacts the elderly. Low estrogen is related to changes in DNA methylation and consequent alterations in gene expression, leading to a new direction in research related to the pathophysiology of osteoporosis. We constructed an Ovariectomized (OVX) mouse model in our study, and the mouse models had osteoporosis based on the phenotype and methylation levels in the mouse’s bone. Furthermore, the methylation level of the OVX mice was significantly changed compared to that of SHAM mice. Therefore, we performed genome-level analysis on the mouse model using transcriptome and Whole Genome Bisulfite Sequencing (WGBS) by combining the data of two omics and discovered that the changes in gene expression level caused by osteoporosis primarily focused on the decrease of bone and muscle development and the activation of the immune system. According to intersection analysis of methylation and transcriptome data, the differentially expressed genes and pathways are consistent with the differentially expressed methylation locations and regions. Further, the differentially expressed methylation sites were mainly concentrated in promoters, exons, and other critical functional regions of essential differentially expressed genes. This is also the primary cause of gene differential expression variations, indicating that estrogen deficiency might regulate gene expression by altering methylation modification, leading to osteoporosis. We demonstrated the clinical value of methylation modification research, and these findings would improve the current understanding of underlying molecular mechanisms of osteoporosis incidence and development and provide new ideas for early detection and treatment of osteoporosis.

Cellular Senescence and Periodontitis: Mechanisms and Therapeutics

Periodontitis is a chronic inflammatory disease which increases in prevalence and severity in the older population. Aging is a leading risk factor for periodontitis, which exacerbates alveolar bone loss and results in tooth loss in the elderly. However, the mechanism by which aging affects periodontitis is not well understood. There is considerable evidence to suggest that targeting cellular senescence could slow down the fundamental aging process, and thus alleviate a series of age-related pathological conditions, likely including alveolar bone loss. Recently, it has been discovered that the senescent cells accumulate in the alveolar bone and promote a senescence-associated secretory phenotype (SASP). Senescent cells interacting with bacteria, together with secreted SASP components altering the local microenvironment and inducing paracrine effects in neighboring cells, exacerbate the chronic inflammation in periodontal tissue and lead to more alveolar bone loss. This review will probe into mechanisms underlying excessive alveolar bone loss in periodontitis with aging and discuss potential therapeutics for the treatment of alveolar bone loss targeting cellular senescence and the SASP. Inspecting the relationship between cellular senescence and periodontitis will lead to new avenues of research in this field and contribute to developing potential translatable clinical interventions to mitigate or even reverse the harmful effects of aging on oral health.

Impact of seborrheic dermatitis on osteoporosis risk: A population‐based cohort study

Osteoporosis is a systemic bone-resorbing disease that easily causes subsequent risk of fracture. Hence, the substantial physical burden of osteoporosis makes it an important public health issue. Seborrheic dermatitis (SD) is a chronic, recurrent, inflammatory skin disease. Despite the advances in medication for treating osteoporosis, identifying undiagnosed osteoporosis patients is still challenging. Since osteoporosis and SD share a similar pathobiology, e.g. inflammation and hormonal imbalance, we aimed to investigate whether the existence of SD increases osteoporosis risk by using the Taiwan National Health Insurance Research Database. A total of 7831 patients aged 18-50 years with SD and a control group of 31 324 patients without SD matched by age, gender, Charlson Comorbidity Index, and index date at a ratio of 1:4 during 1996-2010 were recruited in the study. To measure the cumulative incidence and compare the hazard ratios of osteoporosis between each group, the Kaplan-Meier method and Cox proportional hazard regression models were utilized. It was found that 0.98% of SD patients had osteoporosis. Compared to the non-SD group, the SD group had a 5.95-fold higher osteoporosis risk after adjustment for variables. The impact of SD on osteoporosis risk was largest in the female and young age groups. In addition, the presence of hyperlipidemia, hyperthyroidism, and epilepsy synergistically increased osteoporosis incidence in the SD group. This first large cohort study demonstrated an association between SD and osteoporosis. Since the effect on bone health in SD patients with concomitant diseases is largest in early life, diet or lifestyle recommendations as well as regular bone examinations are advised during follow-up of SD.

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.