Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland

Teeth and alveolar bones as tracers of metals and radionuclides in inhabitants of a uranium region

Biodosimetry can define risks in inhabitants of areas with potential contaminants, ensuring environmental protection and living conditions due to toxic and radioactive effects. This study aimed to evaluate metals and radionuclides in dental structures and alveolar bones in residents of a uranium area in Paraíba and Pernambuco, Brazil. Eighty-nine specimens were pulverized, fractionated, and chemically prepared for analysis by EDXRF, FAAS, and ICP-MS. Levels of Ca, Cu, Fe, Si, Mn, Ni, Pb, Sr, Ti, V, Zn, K, Mn, Th, and U were investigated. Higher concentrations were measured for Ca, with an average of 272,986.4 mg kg-1. Ni presented in lower concentrations, with an average of 30.4 mg kg-1. For U, concentrations ranged from 1.5 to 145.0 mg kg-1, with more than 27% of the samples above the reference value of 8.1 μg kg-1. For Th, almost 38% of the results were above the limit of 3.5 μg kg-1. In the bone spicules, the contents of U and Th ranged from 45.1 to 1451.2 μg kg-1 and from 7.5 to 78.4 μg kg-1, in this order. The levels of radionuclides were more expressive for the teeth collected in São José do Sabugi, suggesting contamination through food and water consumption. In the bone spicules, the levels of U were up to 179 times higher than the safety limit. The results indicate a possible risk of contamination with probable induced radiobiological effects.

A Comparative Study to Explore the Variability of Heavy Metal Concentration in the Teeth of Residents of Non-gated Versus Gated Societies

Human populations face increasing exposure to heavy metals, which pose significant health risks. Dental tissues, such as dentin and enamel, provide a reliable biomarker for assessing long-term heavy metal exposure due to their stable nature. This study aims to explore the variability of heavy metal concentrations in the teeth dentine of residents living in gated versus non-gated societies near the Yamuna River around the Jamia Millia Islamia, New Delhi, India. Sixty-nine participants were enrolled, 27 from gated societies and 42 from non-gated societies. Participants underwent elective dental extraction, following which heavy metal concentrations were measured in extracted tooth dentine using atomic absorption spectrophotometry. Demographic data including age, gender, tooth types, and drinking water sources were recorded. Statistical analysis included Mann-Whitney's test, Spearman correlation heatmap, and principal component analysis (PCA). Residents of non-gated societies exhibited significantly (p < 0.005) higher mean concentrations of heavy metals compared to gated societies except for cadmium (p = 0.495). Subgroup analysis based on drinking water sources revealed significant (p < 0.001) variations in heavy metal concentrations, suggesting the influence of water quality on environmental exposure. PCA provided insights into underlying trends and correlations among heavy metal variables. This study provides valuable insights into heavy metal contamination among residents living near the Yamuna River, highlighting disparities in exposure based on residential environment and drinking water sources. Participants from non-gated societies exhibited higher mean concentrations of heavy metals compared to those from gated societies, emphasizing the influence of socio-economic factors, urban infrastructure and environmental management practices on heavy metal accumulation. The study's findings underscore the need for targeted interventions to address heavy metal exposure across diverse population groups, improve water quality standards, and enhance access to safe drinking water.

Comparative Analysis of Heavy Metal Content in Impacted Third Molars from Industrial and Non-Industrial Areas and Its Effect on the Isolation, Culture, and Proliferation of Dental Stem Cells (DSCs)

Background: This study investigates the impact of environmental pollution on the quality and viability of dental stem cells (DSCs) from impacted third molars. By comparing DSCs from patients in industrial areas with high air pollution and those from non-industrial regions, the research assesses the adverse effects of heavy metals on stem cell proliferation. Methods: Impacted lower third molars were collected from 28 patients-10 from industrial and 18 from non-industrial areas. Patients were divided into two age groups: 18-27 years and 28-38 years old. Dental pulp was extracted under sterile conditions, and DSCs were isolated and cultured. Heavy metal concentrations in dental tissues were measured using atomic absorption/emission spectrometry. Results: The study found significantly higher concentrations of copper and lead in the dental tissues of patients in industrial areas. Cell viability was lower in samples from these areas, with a statistically significant difference in average doubling time and the number of cells obtained after the first passage. There was no significant impact of gender on heavy metal content, except for higher iron levels in men. Conclusions: Exposure to industrial pollutants negatively affects the viability and proliferation of DSCs, but there are no differences in differentiation in the osteogenic medium regarding cell mineralization. These studies highlight the importance of environmental factors for oral health, suggesting that residents of polluted areas may face greater difficulties in dental and regenerative treatments. Further research is needed to develop strategies to mitigate the effects and improve clinical outcomes for affected populations.

Teeth as an Indicator of the Environmental Exposure of Silesia Province's Inhabitants in Poland to Metallic Trace Elements

(1) Background: The elemental composition of teeth can provide an estimate of environmental exposure to heavy metals. The aim of this study was to analyze the possibility of using teeth in the biomonitoring of environmental exposure to heavy metals as an indicator of contaminants present in the human residential environment. (2) Methods: The research materials were 110 samples of extracted teeth. The samples were taken from people living in three areas in the province of Silesia. The concentrations of cadmium, lead, and mercury in the samples were determined. (3) Results: The results of the chemical analysis of the collected samples showed a significant variation in the concentrations of heavy metals (Cd, Pb, and Hg) in the analyzed teeth. Furthermore, the mean concentrations of the analyzed heavy metals in the teeth varied according to the patient's place of residence, the type of tooth analyzed, the presence of caries in the patient, and the smoking or non-smoking status of the patient. (4) Conclusions: The results of the chemical analysis of the teeth of inhabitants of three cities in the most polluted region of Poland indicate that they can be used as an indicator of environmental exposure to cadmium, lead, and mercury.

Surface and Structural Studies of Age-Related Changes in Dental Enamel: An Animal Model

In the animal kingdom, continuously erupting incisors provided an attractive model for studying the enamel matrix and mineral composition of teeth during development. Enamel, the hardest mineral tissue in the vertebrates, is a tissue sensitive to external conditions, reflecting various disturbances in its structure. The developing dental enamel was monitored in a series of incisor samples extending the first four weeks of postnatal life in the spiny mouse. The age-dependent changes in enamel surface morphology in the micrometre and nanometre-scale and a qualitative assessment of its mechanical features were examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM). At the same time, structural studies using XRD and vibrational spectroscopy made it possible to assess crystallinity and carbonate content in enamel mineral composition. Finally, a model for predicting the maturation based on chemical composition and structural factors was constructed using artificial neural networks (ANNs). The research presented here can extend the existing knowledge by proposing a pattern of enamel development that could be used as a comparative material in environmental, nutritional, and pharmaceutical research.

Gradient bimetallic ion-based hydrogels for tissue microstructure reconstruction of tendon-to-bone insertion

Although gradients play an essential role in guiding the function of tissues, achieving synchronous regeneration of gradient tissue injuries remains a challenge. Here, a gradient bimetallic (Cu and Zn) ion-based hydrogel was first constructed via the one-step coordinative crosslinking of sulfhydryl groups with copper and zinc ions for the microstructure reconstruction of the tendon-to-bone insertion. In this bimetallic hydrogel system, zinc and copper ions could not only act as crosslinkers but also provide strong antibacterial effects and induce regenerative capacity in vitro. The capability of hydrogels in simultaneously promoting tenogenesis and osteogenesis was further verified in a rat rotator cuff tear model. It was found that the Cu/Zn gradient layer could induce considerable collagen and fibrocartilage arrangement and ingrowth at the tendon-to-bone interface. Overall, the gradient bimetallic ion-based hydrogel ensures accessibility and provides opportunities to regenerate inhomogeneous tissue with physiological complexity or interface tissue.

Toxic Metals Content in Impacted Third Molars and Adjacent Bone Tissue in Different Groups of Patients

The aim of the study was to determine the content of: Pb, Cd, Cr, Ni, Fe, Mn, Cu, Zn in the impacted third molars and a fragment of covering bone. Patients were divided according to following criteria: place of residence, age, gender, anatomical location of the removed tooth. Content of Cd, Pb, and Mn in the samples increases with age of the patient. The content of Cd and Pb in the tooth and bone was higher in patients living in Wroclaw. Residents of the Wroclaw had higher Cu content in the teeth, while they had a lower content in the jawbone. In contrast to Cd and Pb, an average of 68% higher concentration of Zn in the jawbone than in the tooth was noted. The content of Cr in tooth was lower by 33% than in the mandible bone and, similarly to the content of Ni, it decreased with age. In women, the Fe content in bone of the jaw was higher than in the removed tooth. The presence of Pb and Cd aggregates is confirmed in all hard tissues of the tooth and bone, in contrast to bioelements which show a stronger tendency to aggregate, essentially within the dentine.

Potential effects of noxious chemical-containing fine particulate matter on oral health through reactive oxygen species-mediated oxidative stress: Promising clues

Nowadays, air pollution which is dominated by fine particulate matter with aerodynamic diameter less than or equal to 2.5 µm resulting from rapid industrialization and urbanization combined with population explosion has become more and more severe problem to mankind and the whole planet because of its diversity of deleterious effects. The latest data estimated that exposure to fine particulate matter, or PM2.5, contributes to approximately 4 million deaths worldwide due to cardiopulmonary conditions such as heart disease and stroke, respiratory infections, chronic lung disease and lung cancer. During recent years, there has been growing concern about the adverse effects of this global threat on oral health which is one of key components of general health and quality of life. Although a few studies have reported such possible association, the findings are still far from conclusion. Moreover, the underlying mechanisms remain unclear. To our knowledge, the analysis of literature regarding this scope has yet been published. Thus, current work systematically assesses existing evidences on the potential association between exposure to PM2.5 and the development of various oral diseases as well as figures out the plausible paradigm of PM2.5-induced damages in the oral cavity through its toxic chemical constituents along with its ability to induce oxidative stress via reactive oxygen species production. This might partially provide the clues for new research ideas and progression in the field of oral health.

Characterization of Enamel and Dentine about a White Spot Lesion: Mechanical Properties, Mineral Density, Microstructure and Molecular Composition

The study focuses on in vitro tracing of some fundamental changes that emerge in teeth at the initial stage of caries development using multiple approaches. The research was conducted on a mostly sound maxillary molar tooth but with a clearly visible natural proximal white spot lesion (WSL). Values of mineral density, reduced Young's modulus, indentation hardness and creep as well as the molecular composition and surface microstructure of the WSL and bordering dentine area were studied. The results obtained were compared to those of sound enamel and dentine on the same tooth. A decrease of mechanical properties and mineral density both for the WSL and bordering dentine was detected in comparison to the sound counterparts, as well as increase of creep for the enamel WSL. Differences in molecular composition and surface microstructure (including the indenter impressions) were found and described. WSL induces a serious change in the state of not only the visually affected enamel but also surrounding visually intact enamel and dentine in its vicinity. The results provide the basis for future studies of efficacy of minimal invasive treatments of caries.

Health Effects Associated With Electronic Cigarette Use: Automated Mining of Online Forums

Background

Our previous infodemiological study was performed by manually mining health-effect data associated with electronic cigarettes (ECs) from online forums. Manual mining is time consuming and limits the number of posts that can be retrieved.

Objective

Our goal in this study was to automatically extract and analyze a large number (>41,000) of online forum posts related to the health effects associated with EC use between 2008 and 2015.

Methods

Data were annotated with medical concepts from the Unified Medical Language System using a modified version of the MetaMap tool. Of over 1.4 million posts, 41,216 were used to analyze symptoms (undiagnosed conditions) and disorders (physician-diagnosed terminology) associated with EC use. For each post, sentiment (positive, negative, and neutral) was also assigned.

Results

Symptom and disorder data were categorized into 12 organ systems or anatomical regions. Most posts on symptoms and disorders contained negative sentiment, and affected systems were similar across all years. Health effects were reported most often in the neurological, mouth and throat, and respiratory systems. The most frequently reported symptoms and disorders were headache (n=939), coughing (n=852), malaise (n=468), asthma (n=916), dehydration (n=803), and pharyngitis (n=565). In addition, users often reported linked symptoms (eg, coughing and headache).

Conclusions

Online forums are a valuable repository of data that can be used to identify positive and negative health effects associated with EC use. By automating extraction of online information, we obtained more data than in our prior study, identified new symptoms and disorders associated with EC use, determined which systems are most frequently adversely affected, identified specific symptoms and disorders most commonly reported, and tracked health effects over 7 years.

The effect of cadmium exposition on the structure and mechanical properties of rat incisors

Alterations in the structure and mechanical properties of teeth in adult Wistar rats exposed to cadmium were investigated. Analyses were conducted on two sets of incisors from female and male specimens, that were intoxicated with cadmium (n = 12) or belonged to the control (n = 12). The cadmium group was administered with CdCl2 dissolved in drinking water with a dose of 4mg/kgbw for 10 weeks. The oral intake of cadmium by adult rats led to the range of structural changes in enamel morphology and its mechanical features. A significant increase of cadmium levels in the teeth in comparison to the control, a slight shift in the colour and reduction of pigmented enamel length, higher surface irregularity, a decrease of hydroxyapatite crystals size in the c-axis and simultaneous increase in pigmented enamel hardness were observed. The extent of these changes was sex-dependent and was more pronounced in males.