Copper deficit as a potential pathogenic factor of reduced bone mineral density and severe tooth wear

The impact of copper on bone metabolism

Copper is an essential trace element for the human body. Abnormalities in copper metabolism can lead to bone defects, mainly by directly affecting the viability of osteoblasts and osteoclasts and their bone remodeling function, or indirectly regulating bone metabolism by influencing enzyme activities as cofactors. Copper ions released from biological materials can affect osteoblasts and osteoclasts, either directly or indirectly by modulating the inflammatory response, oxidative stress, and rapamycin signaling. This review presents an overview of recent progress in the impact of copper on bone metabolism. Translational potential of this article: The impact of copper on bone metabolism can provide insights into clinical application of copper-containing supplements and biomaterials.

Risk factors of tooth wear in permanent dentition: A scoping review

BACKGROUND

Tooth wear (TW) prevalence is high and increasing and has important consequences on the patient's quality of life. Knowledge of risk factors is crucial to promote diagnosis, prevention strategies and timely interceptive treatment. Many studies have identified TW risk factors.

OBJECTIVE

This scoping review aims to map and describe suspected available factors associated with TW in permanent dentition based on quantitative measurement.

METHODS

The scoping review was conducted using the PRISMA extension of the Scoping Reviews checklist. The search was conducted in October 2022 from the Medline® (PubMed® interface) and Scopus® databases. Two independent reviewers selected and characterised the studies.

RESULTS

2702 articles were identified for assessment of titles and abstracts, and 273 articles were included in the review. The results show a need to standardise TW measurement indices and the study design. The included studies highlighted various factors, classified into nine domains: sociodemographic factors, medical history, drinking habits, eating habits, oral hygiene habits, dental factors, bruxism and temporomandibular disorders, behavioural factors, and stress. Results related to chemical TW (erosion) risk factors underline the importance of eating disorders, gastroesophageal reflux and lifestyle, particularly drinking and eating behaviours, which supports developing public health information campaigns and interventions. Besides chemical, this review identifies evidence of several mechanical TW risk factors, such as toothbrushing and bruxism; the influence of this last factor needs to be further explored.

CONCLUSIONS

TW management and prevention require a multidisciplinary approach. Dentists are in the first line to detect associated diseases such as reflux or eating disorders. Consequently, practitioners' information and guideline diffusion should be promoted, and a TW risk factors checklist (the ToWeR checklist) is proposed to help diagnostic approaches.

The Homoleptic Curcumin-Copper Single Crystal (ML2): A Long Awaited Breakthrough in the Field of Curcumin Metal Complexes

The first single crystal structure of the homoleptic copper (II) ML2 complex (M=Cu (II), L = curcumin) was obtained and its structure was elucidated by X-ray diffraction showing a square planar geometry, also confirmed by EPR. The supramolecular arrangement is supported by C-H···O interactions and the solvent (MeOH) plays an important role in stabilizing the crystal packing Crystallinity was additionally assessed by XRD patterns. The log P value of the complex (2.3 ± 0.15) was determined showing the improvement in water solubility. The cytotoxic activity of the complex against six cancer cell lines substantially surpasses that of curcumin itself, and it is particularly selective against leukemia (K562) and human glioblastoma (U251) cell lines, with similar antioxidant activity to BHT. This constitutes the first crystal structure of pristine curcumin complexed with a metal ion.

Evaluation of the concentration of selected elements in serum patients with intervertebral disc degeneration

Quantitative analysis of the trace element content of human intervertebral discs (IVDs) is essential because it can identify specific enzymes or metabolites that may be related to human intervertebral disc degeneration (IVDD). The goal of this study was to assess the concentrations of copper (Cu), iron (Fe), manganese (Mn), lead (Pb), zinc (Zn), sodium (Na), magnesium (Mg), potassium (K), phosphorus (P), and calcium (Ca) in serum samples obtained from patients with IVDD in comparison to healthy volunteers (a control group). The study group consisted of 113 Caucasian patients qualified by a specialist neurosurgeon for microdiscectomy. The control group consisted of 113 healthy volunteers who met the eligibility criteria for blood donors. The examined clinical material was the serum samples obtained from both groups.Based on the quantitative analysis of selected elements, there were statistically significantly (p 0.05) higher concentrations of Cu (1180 μg/L±800 μg/L vs. 1230 μg/L±750 μg/L), Zn (790 μg/L±300 μg/L vs. 850 μg/L±200 μg/L), and Mg (21730 μg/L±4360 μg/L vs. 23820 μg/L±4990 μg/L) in the serum of healthy volunteers compared to those in the study group. In addition, statistically significant changes were not detected in the concentrations of any elements among either sex in either the study or control group or in their body mass index (BMI) values (p > 0.05). In the serum samples from the study group, the strongest relationships were noted between the concentrations of Zn and Pb (r = 0.61), Zn and P (r = 0.69), Zn and Ca (r = 0.84), Zn and Cu (r = 0.83), Mg and Ca (r = 0.74), and Ca and P (r = 0.98).It has been indicated that, above all, the concentrations of Cu, Zn, Ca, and Mg depend on the advancement of radiological changes, according to the Pfirrmann scale. However, no influence on pain intensity was found, depending on the concentration of the assessed elements.The analysis indicates that the determination of serum Cu, Zn, Ca, and Mg concentrations may have diagnostic significance in predicting the onset of lumbosacral IVDD. The predictive evaluation of changes in the concentrations of selected elements in patients with degenerative lumbar IVD lesions appears to be a promising, cost-effective strategy.

Copper modified cobalt-chromium particles for attenuating wear particle induced-inflammation and osteoclastogenesis

The nature of aseptic prosthetic loosening mainly relates to the wear particles that induce inflammation and subsequent osteoclastogenesis. The ideal approach to impede wear particle-induced osteolysis should minimize inflammation and osteoclastogenesis. In this work, Co29Cr9W3Cu particles were used as a research model for the first time to explore the response of Co29Cr9W3Cu particles to inflammatory response and osteoclast activation in vitro and in vivo by using Co29Cr9W particles as the control group. In vitro studies showed that the Co29Cr9W3Cu particles could promote the generation of M2-phenotype macrophages and increase the expression level of anti-inflammatory factor IL-10, while inhibiting the formation of M1-phenotype macrophages and down-regulating the expression of inflammatory factors TNF-α, IL-6 and IL-1β; More importantly, the Co29Cr9W3Cu particles reduced the expression of NF-κB and downstream osteoclast related-specific transcription marker genes, such as TRAP, NFATc1, and Cath-K; In vivo results indicated that the Co29Cr9W3Cu particles exposed to murine calvarial contributed to decreasing the amount of osteoclast and osteolysis area. These findings collectively demonstrated that Cu-bearing cobalt-chromium alloy may potentially delay the development of aseptic prosthetic loosening induced by wear particles, which is expected to provide evidence of Co29Cr9W3Cu alloy as an alternative material of joint implants with anti-wear associated osteolysis.

The contemporaneous epidemic of chronic, copper deficiency

The classical deficiency diseases have nearly disappeared from the industrialised world and are thought to be found largely in sub-Saharan Africa and South Asia. More than 80 collected medical articles, mostly from Europe and North America, describe more than 9000 people with low concentrations of copper in organs or tissues or impaired metabolic pathways dependent on copper. More than a dozen articles reveal improved anatomy, chemistry or physiology in more than 1000 patients from supplements containing copper. These criteria are diagnostic of deficiency according to The Oxford Textbook of Medicine. Alzheimer's disease, ischaemic heart disease and osteoporosis receive major emphasis here. However, impaired vision, myelodysplastic syndrome and peripheral neuropathy are mentioned. Copper deficiency probably causes some common, contemporaneous diseases. Advice is provided about opportunities for research. Seemingly authoritative statements concerning the rarity of nutritional deficiency in developed countries are wrong.

The Abundance of Trace Elements in Human Bone Relative to Bone Type and Bone Pathology

As the global population ages and the proportion of individuals afflicted with musculoskeletal disease spirals upward, there is an increasing interest in understanding and preventing bone-related diseases. Bone diseases, such as osteoporosis and osteoarthritis, are known to be influenced by a variety of factors including age, gender, nutrition, and genetics, but are also inherently linked to the human body's ability to produce biominerals of suitable quality. Because the crystal lattice structure and mineralogy of bone hydroxyapatite is surprisingly analogous to geological hydroxyapatite, trace element levels and exposure have long been proposed to influence the structure of biominerals as they do geological minerals (e.g., strontium substitution changes the crystal lattice of bone minerals, while toxic lead disrupt bone cellular processes leading to bone disease). Here, we explore the distribution of trace elements in human bones to evaluate the distribution of these elements with respect to bone type (cortical vs. trabecular) and bone disease (osteoarthritis vs. osteoporosis). We find higher concentrations of many metabolically active transition metals, as well as lead, in cortical bone compared to trabecular bone. When compared to patients who have osteoarthritis, and thus presumably normal bone minerals, osteoporosis patients have higher concentrations of scandium and chromium (Cr) in trabecular bone, and Cr and lead in cortical bone. Lower concentrations of barium and titanium are associated with osteoporotic trabecular bone. This survey is an exploratory cross-sectional geochemical examination of several trace element concentrations previously understudied in human bone minerals.

Characterization of Physical and Biological Properties of a Caries-Arresting Liquid Containing Copper Doped Bioglass Nanoparticles

Silver diamine fluoride (SDF) is an outstanding dental material for arresting and preventing caries, but some drawbacks, such as high flowability due to low viscosity and cytotoxicity to the pulp, have been reported. To overcome these problems, copper-doped bioactive glass nanoparticles (CuBGns) were combined with SDF. After synthesis, CuBGns were examined by physical analysis and added in SDF at different weight/volume% (SDF@CuBGn). After assessing physical properties (viscosity and flowability) of SDF@CuBGn, physicochemical properties (morphology before and after simulated body fluid (SBF) immersion and ion release) of SDF@CuBGn-applied hydroxyapatite (HA) discs were evaluated. Biological properties were further evaluated by cytotoxicity test to pulp stem cells and antibacterial effect on cariogenic organisms (Streptococcus mutans and Staphylococcus aureus). Combining CuBGns in SDF increased the viscosity up to 3 times while lowering the flowability. More CuBGns and functional elements in SDF (Ag and F) were deposited on the HA substrate, even after SBF immersion test for 14 days, and they showed higher Cu, Ca, and Si release without changing F and Ag release. Cell viability test suggested lower cytotoxicity in SDF@CuBGn-applied HA, while CuBGns in SDF boosted antibacterial effect against S. aureus, ~27% in diameter of agar diffusion test. In conclusion, the addition of CuBGn to SDF enhances viscosity, Ag and F deposition, and antibacterial effects while reducing cell toxicity, highlighting the role of bioactive CuBGns for regulating physical and biological effects of dental materials.

Effect of masseter muscle activity during wakefulness and sleep on tooth wear

PURPOSE

To investigate the effect of masseter muscle activity during wakefulness and sleep on tooth wear.

METHODS

Sixteen participants with no or mild tooth wear (NMTW group) and sixteen participants with moderate-to-severe tooth wear (MSTW group) were enrolled. The severity of tooth wear was evaluated using the occlusal and incisal indices of the tooth wear index. Surface electromyography was performed to record the electrical activity of the left masseter muscle during wakefulness and sleep. Electromyographic activity was detected using an electromyographic threshold of 5% and 20% of maximal voluntary clenching (MVC). The total duration of electromyographic activity and bruxism episodes were calculated.

RESULTS

The mean ages of the NMTW and MSTW groups were 71.75 ± 7.61 years and 71.69 ± 7.49 years, respectively. The mean cumulative duration of electromyographic activity during wakefulness using a threshold of >5% MVC was 6.44 ± 4.52 min/h and 13.62 ± 10.08 min/h for the NMTW and MSTW groups, respectively (p=0.048). The mean total durations of electromyographic activity during wakefulness and sleep using a threshold of >20% MVC were 1.08 ± 1.70 min/h and 1.05 ± 3.02 min/h, respectively, in the NMTW group and 4.78 ± 6.37 min/h and 1.61 ± 1.79 min/h, respectively, in the MSTW group (p=0.048 and p=0.003, respectively).

CONCLUSION

These results suggest that masseter electromyographic activity during wakefulness and sleep may be related to the severity of tooth wear.

Do Only Calcium and Vitamin D Matter? Micronutrients in the Diet of Inflammatory Bowel Diseases Patients and the Risk of Osteoporosis

Osteoporosis is one of the most common extraintestinal complications among patients suffering from inflammatory bowel diseases. The role of vitamin D and calcium in the prevention of a decreased bone mineral density is well known, although other nutrients, including micronutrients, are also of extreme importance. Despite the fact that zinc, copper, selenium, iron, cadmium, silicon and fluorine have not been frequently discussed with regard to the prevention of osteoporosis, it is possible that a deficiency or excess of the abovementioned elements may affect bone mineralization. Additionally, the risk of malnutrition, which is common in patients with ulcerative colitis or Crohn's disease, as well as the composition of gut microbiota, may be associated with micronutrients status.

Tuning osteoporotic macrophage responses to favour regeneration by Cu-bearing titanium alloy in Porphyromonas gingivalis lipopolysaccharide-induced microenvironments

Guided bone regeneration in inflammatory microenvironments of osteoporotic patients with large alveolar bone defects remains a great challenge. Macrophages are necessary for alveolar bone regeneration via their polarization and paracrine actions. Our previous studies showed that Cu-bearing Ti6Al4V alloys are capable of regulating macrophage responses. When considering the complexity of oral microenvironments, the influences of Cu-bearing Ti6Al4V alloys on osteoporotic macrophages in infectious microenvironments are worthy of further investigations. In this study, we fabricated Ti6Al4V-Cu alloy by selective laser melting technology and used Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) to imitate oral pathogenic bacterial infections. Then, we evaluated the impacts of Ti6Al4V-Cu on osteoporotic macrophages in infectious microenvironments. Our results indicated that Ti6Al4V-Cu not only inhibited the P.g-LPS-induced M1 polarization and pro-inflammatory cytokine production of osteoporotic macrophages but also shifted polarization towards the pro-regenerative M2 phenotype and remarkably promoted anti-inflammatory cytokine release. In addition, Ti6Al4V-Cu effectively promoted the activity of COMMD1 to potentially repress NF-κB-mediated transcription. It is concluded that the Cu-bearing Ti6Al4V alloy results in ameliorated osteoporotic macrophage responses to create a favourable microenvironment under infectious conditions, which holds promise to develop a GBR-barrier membrane for alveolar bone regeneration of osteoporosis patients.

The associations between serum trace elements and bone mineral density in children under 3 years of age

We examined the associations of age and serum magnesium, iron, lead, copper, and zinc levels with bone mineral density (BMD) in 2412 children under 3 years of age in order to find a tool to monitor BMD in children without the use of expensive imaging techniques. One-way ANOVA and chi-square tests were used to determine the associations of age and serum trace elements with BMD. Multivariable logistic regression analysis was used to test the correlation of five serum trace elements with BMD after adjustments for potential confounding factors in children under 3 years of age. Significant associations between age and four serum trace elements and BMD were found. Compared to the group with the lowest serum levels detected, the adjusted odds ratio (OR) for the incidence of normal bone mineral density in the third magnesium concentration tertile, the third iron concentration tertile, the fifth copper concentration quintile, the third zinc concentration quintile, and the fifth zinc concentration quintile were 1.30 (95% confidence interval (CI) 1.02–1.67), 1.43 (95% CI 1.11–1.84), 1.42 (95% CI 1.04–1.94), 1.46 (95% CI 1.05–2.04), and 1.48 (95% CI 1.06–2.06), respectively. However, there was no significant correlation between serum lead level and BMD in this study. Age and serum magnesium, iron, copper, and zinc levels are positively associated with BMD in children under 3 years old.

Salivary Content Might be Associated With Skeletal Status in Postmenopausal Women: SilesiaOsteoActive Study Results

AIM

The aim of the study was to investigate whether salivary mineral content may be associated with bone status in women after menopause.

MATERIAL AND METHODS

The study group consisted of 125 postmenopausal women aged 64.3 ± 6.9 yr, derived from the epidemiological SilesiaOsteoActive Study. All participants underwent hip and spine bone densitometry using dual energy X-ray absorptiometry, dental examination, and saliva content analysis. Data for salivary pH, copper, calcium, phosphorus, and zinc concentrations were evaluated.

RESULTS

Mean femoral neck bone mineral density (BMD) was 0.739 ± 0.118 g/cm², total hip BMD 0.891 ± 0.14 g/cm², and spine BMD 0.868 ± 0.14 g/cm². Salivary pH was significantly lower in women with spinal osteoporosis defined as T-score below -2.5, compared to individuals with normal BMD (pH: 6.65 ± 0.67 vs 6.96 ± 0.58, p < 0.05). There was a significant though weak inverse correlation between Ca concentration in saliva and femoral neck BMD (r = -0.23, p < 0.05).

CONCLUSIONS

High salivary calcium content and low salivary pH may be indicative of low hip and decreased spine BMD, respectively. These associations may reflect demineralization process (calcium redistribution) influencing bone, and a negative effect of acidity on mineral tissues, although causal pathway remains not clear.

The Impact of Trace Minerals on Bone Metabolism

Bone is a metabolically active tissue that responds to alterations in dietary intake and nutritional status. It is ~ 35% protein, mostly collagen which provides an organic scaffolding for bone mineral. The mineral is the remaining ~ 65% of bone tissue and composed mostly of calcium and phosphate in a form that is structurally similar to mineral within the apatite group. The skeletal tissue is constantly undergoing turnover through resorption by osteoclasts coupled with formation by osteoblasts. In this regard, the overall bone balance is determined by the relative contribution of each of these processes. In addition to macro minerals such as calcium, phosphorus, and magnesium which have well-known roles in bone health, trace elements such as boron, iron, zinc, copper, and selenium also impact bone metabolism. Effects of trace elements on skeletal metabolism and tissue properties may be indirect through regulation of macro mineral metabolism, or direct by affecting osteoblast or osteoclast proliferation or activity, or finally through incorporation into the bone mineral matrix. This review focuses on the skeletal impact of the following trace elements: boron, iron, zinc, copper, and selenium, and overviews the state of the evidence for each of these minerals.

Copper-Modified Ti6Al4 V Suppresses Inflammatory Response and Osteoclastogenesis while Enhancing Extracellular Matrix Formation for Osteoporotic Bone Regeneration

Copper has been reported to promote bone regeneration by increasing osteogenesis and decreasing inflammation and osteoclastogenesis. However, information on the effects of copper on osteoporotic cells involved in bone regeneration is scarce in the literature. In the current study, Ti6Al4 V-6 wt %Cu (Ti6Al4 V-Cu) was fabricated by selective laser melting (SLM) technology, and the effects of copper on the behaviors of osteoporotic and nonosteoporotic macrophages, osteoclasts, and osteoblasts were evaluated by comparison with Ti6Al4 V. Our results showed that Ti6Al4 V-Cu inhibited the activation, viability, and pro-inflammatory cytokine secretion of osteoporotic macrophages and decreased osteoclast formation and down-regulated osteoclast differentiation-related genes and proteins of osteoporotic osteoclasts. Furthermore, the bone extracellular matrix formation of osteoporotic osteoblasts was up-regulated by Ti6Al4 V-Cu. In conclusion, SLM-fabricated Ti6Al4 V-Cu exhibited excellent anti-inflammation and antiosteoclast capability, optimized extracellular matrix formation, and holds great potential for bone regeneration in osteoporotic patients.

The Coordination Abilities of Three Novel Analogues of Saliva Peptides: The Influence of Structural Modification on the Copper Binding

Three novel analogues of salivary peptides as sialorphin (QHNPR) and opiorphin (QRFSR) were synthesized by the solid-phase method. The sequences of these ligands were following: AHNPR, QANPR and QRFPR. The aim of our work was investigation in what way some structural modifications may impact on coordination abilities of studied peptides. In this work we presented the interaction of pentapeptides with copper(II) ions in wide range of pH. To determine the coordination model of ligands there were carried out several studies by spectroscopy (UV–Vis, CD) methods and potentiometric measurements.

Trace elements have beneficial, as well as detrimental effects on bone homeostasis

The protective role of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well understood. In addition, integrity of the skeleton is positively influenced by certain trace elements (e.g. zinc, copper, manganese, magnesium, iron, selenium, boron and fluoride) and negatively by others (lead, cadmium, cobalt). Deficiency or excess of these elements influence bone mass and bone quality in adulthood as well as in childhood and adolescence. However, some protective elements may become toxic under certain conditions, depending on dosage (serum concentration), duration of treatment and interactions among individual elements. We review the beneficial and toxic effects of key elements on bone homeostasis.

Copper, iron, and selenium dietary deficiencies negatively impact skeletal integrity: A review

Nutrients have been known to have a significant role in maintaining the health of the skeleton, both bone and cartilage. The nutrients that have received the majority of the attention are Vitamin D and calcium. However, limited attention has been directed toward three trace elements that may have mechanistic impact upon the skeletal tissues and could compromise skeletal health resulting from inadequate intakes of copper, iron, and selenium. The role of copper and selenium has been known, but the role of iron has only received recent attention. Copper deficiency is thought to impact bone health by a decrease in lysyl oxidase, a copper-containing enzyme, which facilitates collagen fibril crosslinking. Iron deficiency impact upon bone has only recently been discovered but the exact mechanism on how the deficient states enhance bone pathology is speculative. Selenium deficiency has an impact on cartilage thereby having an indirect impact on bone. However, several studies suggest that a mycotoxin when consumed by humans is the culprit in some cartilage disorders and the presence of selenium could attenuate the pathology. This review summarizes the current knowledge base with respect to skeletal integrity when each of these three trace elements are inadequate in diets of both animals and humans.

Microscopic structure of dental hard tissues in primary and permanent teeth from individuals with Prader-Willi syndrome

OBJECTIVE

severe tooth wear, in terms of both erosive wear and attrition, is a significant problem in individuals with Prader-Willi syndrome (PWS). The purpose of the present study was to describe the structure of enamel and dentine in primary and permanent teeth from individuals with PWS.

DESIGN

thirty-two primary and 10 permanent teeth representing 16 individuals with PWS were investigated in the study. The enamel surface was studied using scanning electron microscopy (SEM). The microscopic structure of enamel and dentine was studied using SEM, microradiography and light microscopy.

RESULTS

the microscopic structure of enamel and dentine was found to be normal with the exception of a slight increase of interglobular dentine (IGD). Severe erosive defects were observed in primary teeth and also in permanent teeth with long exposure to the oral environment.

CONCLUSION

the erosive enamel defects in individuals with PWS seem more related to the factors in the oral environment than to enamel structure which appeared normal. The occurrence of IGD indicate deficient mineralization but is probably of minor clinical significance. Gastro-oesophageal reflux is worthy of further investigation in individuals with Prader-Willi syndrome.

Implant-Supported Prosthetic Rehabilitation of a Patient with Localized Severe Attrition: A Clinical Report

Patients usually adapt to their existing occlusal vertical dimension (OVD). It is essential to resolve each of the problems associated with decreased vertical dimension as a result of attrition. This report describes the multidisciplinary dental treatment of a 40-year-old male patient who had severe tooth wear, resulting in reduced vertical dimension. After clinical evaluations, extraoral examination showed a reduction of the lower facial height, drooping, and overclosed commissures. Ten dental implants were placed into the maxillary and mandibular alveolar processes. During the osseointegration period, an interim removable partial denture was made at increased OVD to use in the first stage of rehabilitation. It was used for 3 months as a guide for preparing the definitive restorations. The patient's adaptation to the increased OVD was evaluated. During this period, he was asymptomatic. Following the evaluation period, the provisional fixed restoration was used for 3 months. Then, full-mouth definitive prostheses supported by a combination of implants and teeth were fabricated to upper and lower jaws. Osseointegration of the implants, peri-implant mucosa health, prosthesis function, and esthetics were assessed after 1 week and 1, 3, and 6 months. After 3 years of follow-up, no functional or esthetic difficulties with the implants and restorations were noted.