Effects of smoking on trace metal levels in saliva

Salivary Chromium and Cobalt Concentrations in Patients with Dental Metallic Restorations-A Pilot Study

Introduction: Metal ions, released from dental alloys due to corrosion, come in contact with the cells of the surrounding tissues and may spread throughout the body via the gastrointestinal system, thus inducing dose-dependent cytopathological effects. This study aimed to assess and compare the salivary cobalt and chromium concentrations in individuals aged 18-65 years with and without dental restorations containing metal alloys. Methods: Participants were divided into two main groups according to the existence of metal alloys in the oral cavity-18 patients had fixed prosthetic restorations made of metal alloys, and 17 patients had no metal objects in their oral cavity. Each main group was subdivided into two subgroups according to the type of saliva sample-with or without additional stimulation. Salivary cobalt and chromium concentrations were measured by inductively coupled plasma mass spectrometry. A non-parametric Mann-Whitney test and Spearman's rank correlation coefficient were applied, and the level of significance was set to p < 0.05. Results: The results showed that the chromium level in non-stimulated saliva was higher in the group of patients with metal dental restorations. No statistical difference was found in cobalt levels. There was no statistical difference in Co or Cr concentrations in stimulated saliva between the studied groups. A positive correlation was found between Cr and Co concentrations in non-stimulated saliva and between cobalt concentrations in stimulated and non-stimulated saliva. Conclusions: Metal alloys in the oral cavity induced elevated chromium levels in non-stimulated saliva, and a correlation between chromium and cobalt ion concentration was found. A detailed examination of patients and their medical history prior to prosthetic treatment is advisable in order to avoid any undesired health effects.

Insights into the Chemistry, Structure, and Biological Activity of Human Salivary MUC7 Fragments and Their Cu(II) and Zn(II) Complexes

Mucin 7 (MUC7) is one of the salivary proteins whose role in the innate immune system is widely known, but still, neither its mechanism of action nor the impact of its metal coordination is fully understood. MUC7 and its fragments demonstrate potent antimicrobial activity, serving as a natural defense mechanism for organisms against pathogens. This study delves into the bioinorganic chemistry of MUC7 fragments (L1─EGRERDHELRHRRHHHQSPK; L2─EGRERDHELRHRR; L3─HHHQSPK) and their complexes with Cu(II) and Zn(II) ions. The antimicrobial characteristics of the investigated peptides and their complexes were systematically assessed against bacterial and fungal strains at pH 5.40 and pH 7.40. Our findings highlight the efficacy of these systems against Streptococcus sanguinis, a common oral cavity pathogen. Most interestingly, Zn(II) coordination increased (or triggered) the MUC7 antimicrobial activity, which underscores the pivotal role of metal ion coordination in governing the antimicrobial activity of human salivary MUC7 fragments against S. sanguinis.

[Oral microbiota and liver]

The liver has many important biological functions for the body, as it is involved in the storage and distribution of nutrients (carbohydrates to glycogen, lipids to triglycerides), the digestion of fats, the synthesis of blood proteins, and the detoxification of alcohol and drugs. The liver can be affected by various diseases such as viral or drug-induced hepatitis, fibrosis and cirrhosis, in which damaged hepatocytes are progressively replaced by scar tissue.

Environmental tobacco smoke exposure is associated with increased levels of metals in children's saliva

BACKGROUND

Exposure to environmental tobacco smoke (ETS) has been associated with detectable levels of cotinine (a nicotine metabolite) in children's saliva. However, tobacco smoke also contains toxic and essential trace metals, including chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn).

OBJECTIVE

The current study examines whether there is a relationship between ETS exposure, as gauged by salivary cotinine, and salivary levels of these metals in a subset (n = 238) of children from the Family Life Project.

METHODS

Using inductively-coupled-plasma optical emission spectrophotometry, we measured levels of metals in saliva from children at ~90 months of age. Salivary cotinine was measured using a commercial immunoassay.

RESULTS

We found that Cr, Cu, Mn, and Zn were detected in most samples (85-99%) with lower levels of detection for Pb and Ni (9.3% and 13.9% respectively). There were no significant differences in any of the metal concentrations between males and females, nor were levels associated with body mass index, although significant differences in salivary Cr and Mn by race, state and income-to-needs ratio were observed. Children with cotinine levels >1 ng/ml had higher levels of Zn (b = 0.401, 95% CI: 0.183 to 0.619; p = 0.0003) and Cu (b = 0.655, 95% CI: 0.206 to 1.104; p = 0.004) compared to children with levels <1 ng/ml, after controlling for multiple confounders, including sex, race, BMI and income-to-needs ratio. Further, we show that children whose cotinine levels were >1 μg/L were more likely to have detectable levels of Pb in their saliva (b = 1.40, 95% CI: 0.424 to 2.459; p = 0.006) compared to children with cotinine levels <1 ng/ml, also considering confounders.

IMPACT STATEMENT

This is the first study to demonstrate significant associations between salivary cotinine and salivary levels of Cu, Zn and Pb, suggesting that environmental tobacco smoke exposure my be one source of increased children's exposure to heavy metals. This study also demonstrates that saliva samples can be used to measure heavy metal exposure, and thus serve as a non-invasive tool for assessing a broader range of risk indicators.

Determination of 14 trace elements in blood, serum and urine after environmental disaster in the Doce River basin: Relationship between mining waste and metal concentration in the population

BACKGROUND

Exposure to chemical substances after an environmental disaster can cause both toxic effects and changes in the health status of people who live in or have proximity to environments of this nature, so that the concern with populations is growing.

METHODS

In this cross-sectional study, blood, serum and urine samples were collected from 100 volunteers from Santo Antônio do Rio Doce, eight from Ilha das Pimentas and 50 from the control group; and analyzed by inductively coupled plasma mass spectrometry for biomonitoring of Al, As, Ba, Cd, Co, Cu, Cr, Fe, Hg, Mn, Ni, Se, Pb, Zn. In addition, a comprehensive questionnaire was applied to collect demographic and socioeconomic information, as well as lifestyle.

RESULTS

The concentrations of As, Al, Cd, Ni and Mn were above the reference value in some biological matrices, with more pronounced exposure in Ilha das Pimentas. The concentrations of As, Cd, Cu, Co, Pb and Zn showed statistical differences regarding gender in the different biological matrices. The trace elements in the blood, serum and urine showed significant correlations when considering age and habits such as the consumption of cigarettes, alcoholic beverages and fish. The main correlations were observed between Co, Cr, Mn, Ni and Pb in the blood and cigarette consumption.

CONCLUSION

This is the first study in these regions after the environmental disaster and confirmation of the diagnosis and health care of the participants should be promoted for clinical investigation and the eventual need for treatment. Human biomonitoring demonstrated high concentrations of some toxic elements, with more accentuated exposure in Ilha das Pimentas.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Correlation between Metal Ions and Cytokines in the Saliva of Patients with Oral Lichenoid Lesions

PURPOSE

We aimed to investigate the effect of metal ions from oral prostheses (OPs) released into the saliva of patients with oral lichenoid lesions (OLLs).

MATERIALS AND METHODS

Subjects (n=183) were divided into four groups according to the presence or absence of OLL and OP. Concentrations of the metal ions titanium, chromium (Cr), cobalt (Co), nickel (Ni), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), and zirconium (Zr) were measured using a laser-ablation microprobe inductively coupled to a plasma mass spectrometer. Saliva levels of interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor-α were detected using an enzyme-linked immunosorbent assay. The reticulation/keratosis, erythema, and ulceration (REU) scoring system was used to assess the severity of OLL.

RESULTS

Mean concentrations of IL-6 and IL-8 were statistically higher in OLL patients with OPs. The concentration of Ni was high in OLL groups. The concentrations of Cr, Ni, and Au ions in the saliva were positively correlated with IL-8. REU scores were positively correlated with salivary concentrations of IL-6 and IL-8, as well as with concentrations of Cr, Ni, and Au.

CONCLUSION

Increased concentrations of metal ions, especially Ni, in saliva were positively correlated with IL-8 and showed positive correlations with the severity of OLL.

Serum Magnesium and Fractional Exhaled Nitric Oxide in Relation to the Severity in Asthma-Chronic Obstructive Pulmonary Disease Overlap

Serum concentrations of magnesium and manganese may be associated with increased chronic obstructive pulmonary disease exacerbation risk. However, associations with other aspects of asthma-chronic obstructive pulmonary disease overlap, pulmonary function test results and health status, have been studied less extensively. The aim of this study was to investigate the associations between serum concentrations of trace elements and T lymphocyte subsets, FeNO, and COPD-related questionnaire scores in individuals with ACO and the potential impact of these parameters on lung function. All the patients met the diagnostic criteria of ACO and were divided into two groups (group A, mild-moderate; group B, severe-very severe) by their specific characteristics. Pulmonary function testing and serum Mg and serum Mn and FeNO were measured. Four hundred sixty-five patients were screened, and 42 were included. Group A had significantly higher Mg and Fe concentrations than group B. No significant differences were seen in the serum concentration of any other trace element between the two groups. Serum Mg and Mn were correlated with FEV1% predicted (p < 0.01). Group A had a significantly higher FeNO concentration than group B (p = 0.005). The scores on CAT (p = 0.011) and mMRC (p = 0.008) in group A were lower than in group B. The low-FeNO group had a significantly lower concentration of serum Mg than the high-FeNO group (p = 0.03). Pulmonary function declined faster (p < 0.05) in the low-FeNO group than the high-FeNO group. Serum Mg concentration may indicate protective effects against lung function loss in ACO. This implies that FeNO might be a biomarker for identifying individuals with ACO who might benefit from inhaled corticosteroid therapy. Serum Mg and FeNO were associated with ACO severity. However, their role in guiding personalised treatment of individuals with ACO needs to be further investigated.

Use of toenail-bounded heavy metals to characterize occupational exposure and oxidative stress in workers of waterpipe/cigarette cafés

Tobacco smoke is known for releasing metals in indoor air of waterpipe/cigarette cafés. However, the worker exposure to metals, and its association with oxidative stress in these cafés are still unclear. To this end, 54 workers and 38 customers from waterpipe/cigarette cafés (the exposed group), 30 workers from non-smoking cafés (the control group 1 (CG_1)) and 32 individuals from the general population (the control group 2 (CG_2)) were selected and toenails samples were then taken from them. Our findings revealed a significant difference in terms of toenail-bounded metal levels between the exposure and control groups (CG_1 and CG_2) (Mann-Whitney U test, Pvalue < 0.05). This study has also indicated that "type of tobacco" could be considered as a predictor for toenail-bounded heavy metals. Furthermore, our research's results suggest that toenail-bounded heavy metals are positively and significantly correlated with urinary levels of 8- hydroxy-2'-deoxyguanosine (8-OHdG, as a biomarker for the degradation of deoxyribonucleic acid (DNA) oxidative stress). Therefore, it can be concluded that workers of waterpipe/cigarette cafés are at high risks of adverse health of DNA oxidative degradation.

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

ICP-Mass-Spectrometry Ionic Profile of Whole Saliva in Patients with Untreated and Treated Periodontitis

Over the past decade, there has been growing interest in the association between macro and trace minerals in body fluids and systemic diseases related to chronic inflammation and oxidative stress. Due to the paucity of data in the literature on periodontitis, the aim of this cross-sectional study was to assess the relationship between mineral elements in saliva and periodontal status in patients with untreated and treated periodontitis compared to periodontally healthy controls. Salivary samples from 66 nonsmoker healthy patients (20 periodontally healthy, 24 untreated severe periodontitis and 22 treated severe periodontitis) were analyzed by using inductively coupled plasma mass-spectrometry (ICP-MS). Significant increases in copper (Cu), sodium (Na), iron (Fe) and manganese (Mn) concentrations occurred in saliva of severe periodontitis subjects compared to periodontally healthy controls. No differences were detected between healthy controls and treated periodontitis patients apart from levels of zinc (Zn) and lithium (Li) that were found to be increased and reduced, respectively, in periodontitis group. Most subjects were correctly separated by cluster analysis into active periodontitis and periodontally healthy individuals. Treated periodontitis individuals were classified as healthy subjects. Based on these preliminary results, the assessment of salivary concentration of mineral elements might be useful in discriminating periodontal health and disease.

Candida albicans Interactions with Mucosal Surfaces during Health and Disease

Flexible adaptation to the host environment is a critical trait that underpins the success of numerous microbes. The polymorphic fungus Candida albicans has evolved to persist in the numerous challenging niches of the human body. The interaction of C. albicans with a mucosal surface is an essential prerequisite for fungal colonisation and epitomises the complex interface between microbe and host. C. albicans exhibits numerous adaptations to a healthy host that permit commensal colonisation of mucosal surfaces without provoking an overt immune response that may lead to clearance. Conversely, fungal adaptation to impaired immune fitness at mucosal surfaces enables pathogenic infiltration into underlying tissues, often with devastating consequences. This review will summarise our current understanding of the complex interactions that occur between C. albicans and the mucosal surfaces of the human body.

Analysis of the Relationship Between Hemorheologic Parameters, Aluminum, Manganese, and Selenium in Smokers

Smoking is a significant risk factor in fatal pathologies including cardio-cerebrovascular and respiratory diseases. Aluminum (Al) is a toxic element without known biological function, but with recognized toxic effects. Manganese (Mn) and selenium (Se) are essential trace elements involved in cellular antioxidant defense mechanisms. Al, Mn, and Se carry out their metabolic activities via blood flow and tissue oxygenation. The structure and number of red blood cells (RBC) play important role in tissue oxygenation throughout blood flow. Increased hematocrit (Hct) as a result of probable hypoxia induces disturbed blood flow, RBC aggregation (RBC Agg), RBC deformability index (Tk), and oxygen delivery index (ODI). Therefore, we aimed to investigate the effects of altered Al, Mn, and Se levels on number, structure, and function of RBCs (Hct, blood and plasma viscosity (BV and PV, respectively), RBC Agg, Tk, ODI) in smokers without diagnosis of chronic obstructive pulmonary disease (COPD) in a study group (n = 128) categorized as ex-smokers (ES), smokers (S), and healthy controls (HC). Elements were analyzed in serum using ICP-OES. BV and PV were measured via Brookfield and Harkness viscometers at 37 °C, respectively. Smokers had statistically higher serum Al and Mn levels, BV, RBC, Hgb, Hct, PV, fibrinogen, RBC Agg, Tk₄₅, and pulmonary blood flow rate, but lower serum Se levels and ODI₄₅ values versus HC. In conclusion, increased Al, Mn, and hemorheological parameters and decreased Se and ODI₄₅ might result from inflammatory response in defense mechanism in smokers without diagnosis of COPD. Our results point out that serum Al, Mn, and Se with hemorheological parameters may be beneficial markers of tissue oxygenation and defense mechanism before the clinic onset of COPD in smokers.

Quantification of 71 detected elements from Li to U for aqueous samples by simultaneous-inductively coupled plasma-mass spectrometry

Quantitative analysis of multi-element concentrations in aqueous solutions, such as water, beverages and biofluids, has long been performed by sequential inductively coupled plasma-mass spectrometry. Recently, a fully simultaneous mass spectrum monitoring ICP-MS instrument that fits a compact Mattauch-Herzog geometry (MH-ICP-MS) with a permanent magnet and a large, spatially resolving semiconductor ion detector has been introduced. This technology allows coverage of the complete inorganic relevant mass range from 6Li to 238U in a single measurement, which helps to mitigate the restriction on the number of inorganic elements whose concentrations may be routinely measured from one sample, thus reducing operational assay times and aqueous sample volumes for evaluations across the breadth of the periodic table. We report here on a detailed method for utilizing MH-ICP-MS to detect all elements of the relevant inorganic spectrum in aqueous samples; 7 types of water, 4 types of beverage, and 4 biofluid biological samples. With this method 71 elements can be routinely detected simultaneously in seconds and in as little as 1-4 mL sample, when using a specific set of calibration and internal standards. Quantitative results reveal distinct element patterns between each sample and within types of samples, suggesting that different types of aqueous solutions can be recognized and distinguished by their elemental patterns. The method has implications for understanding elemental distribution and concentration for many fields, including nutrition, studies of the biosphere, ecological stoichiometry, and environmental health fields, among others, where broad elemental information is actually required.

Body burden of toxic metals and rare earth elements in non-smokers, cigarette smokers and electronic cigarette users

Smoking is considered an important source for inorganic elements, most of them toxic for human health. During the last years, there has been a significant increase in the use of e-cigarettes, although the role of them as source of inorganic elements has not been well established. A cross-sectional study including a total of 150 subjects from Brasov (Romania), divided into three groups (non-smokers, cigarette smokers and electronic cigarettes smokers) were recruited to disclose the role of smoking on the human exposure to inorganic elements. Concentration of 42 elements, including trace elements, elements in the ATSDR's priority pollutant list and rare earth elements (REE) were measured by ICP-MS in the blood serum of participants. Cigarette smokers showed the highest levels of copper, molybdenum, zinc, antimony, and strontium. Electronic cigarette (e-cigarette) users presented the highest concentrations of selenium, silver, and vanadium. Beryllium, europium and lanthanides were detected more frequently among e-cigarette users (20.6%, 23.5%, and 14.7%) than in cigarette smokers (1.7%, 19.0%, and 12.1%, respectively); and the number of detected REE was also higher among e-cigarette users (11.8% of them showed more than 10 different elements). Serum levels of cerium and erbium increased as the duration of the use of e-cigarettes was longer. We have found that smoking is mainly a source of heavy metals while the use of e-cigarettes is a potential source of REE. However, these elements were detected at low concentrations.

Cadmium Profiles in Dental Calculus: a Cross-Sectional Population-Based Study in Hunan Province of China

We aimed to investigate whether the cadmium concentrations differ in human dental calculus obtained from the residents with no smoking living in the contaminated area and those with no smoking living in noncontaminated area. In total, there were 260 samples of dental calculus from the adults (n = 50) with no smoking living in contaminated area, the adults (n = 60) with no smoking living in mountainous area, and the adults (n = 150) with no smoking living in low altitude area in Hunan province of China. All samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for cadmium levels. The cadmium levels in dental calculus were significantly higher in the adults with no smoking living in contaminated area than those living in mountainous area and in low altitude area (p < 0.01). The cadmium levels in dental calculus were also higher in the adults with no smoking living in low altitude area than those living in mountainous region (p < 0.01). The results suggested that measuring cadmium levels in dental calculus may be a useful noninvasive method for analysis of environmental exposure to cadmium in the human oral cavity. The low altitude region may have an area contaminated with cadmium in Hunan province of China.

Clinical and radiographic periodontal status and whole salivary cotinine, IL-1β and IL-6 levels in cigarette- and waterpipe-smokers and E-cig users

The aim was to compare the clinical (plaque index [PI], bleeding on probing [BOP], probing pocket depth [PPD] and clinical attachment loss [CAL]) and radiographic (marginal bone loss [MBL]) periodontal parameters and whole salivary cotinine, interleukin (IL)-1β and IL-6 levels among cigarette-smokers, waterpipe-smokers, E-cig users and never-smokers. In total, 154 male individuals (39 cigarette-smokers, 40 waterpipe-smokers, 37 E-cig users and 38 never-smokers) were included. Full mouth PI, BOP, PPD and CAL were measured on all teeth (excluding third molars); and MBL was measured in digital intra-oral radiographs. Unstimulated whole salivary flow rate (UWSFR) and whole salivary cotinine, IL-1β and IL-6 levels were measured. Group comparisons were performed using one way analysis of variance and Bonferroni post-hoc tests. P-values less than 0.05 were considered statistically significant. There was no difference in UWSFR among the groups. Cotinine levels were significantly higher among cigarette- (P < 0.001) and waterpipe-smokers (P < 0.001) and E-cig users (P < 0.001) than never-smokers. IL-1β (P < 0.01) and IL-6 (P < 0.01) levels were significantly higher among cigarette- and waterpipe-smokers than E-cig users and never-smokers. There was no difference in PPD, CAL, mesial and distal MBL and whole salivary IL-1β and IL-6 levels among E-cig users and never-smokers. In conclusion, clinical and radiographic parameters of periodontal inflammation were poorer in cigarette and waterpipe smokers than E-cig users and never-smokers; and whole salivary cotinine levels were similar in all groups. Whole salivary IL-1β and IL-6 levels were higher in cigarette- and waterpipe-smokers than E-cig users and never-smokers.

Salivary metals, age, and gender correlate with cultivable oral Candida carriage levels

Background: Little is known about the normal range of metal levels in unstimulated saliva, nor whether these might impact Candida carriage in healthy individuals. Both are important in determining which populations are at risk for candidiasis, as the availability of metal ions can influence the growth and pathogenesis of Candida albicans.

Objective: We quantified salivary metals of healthy individuals to determine the correlation with C. albicans oral colonization.

Design: Unstimulated whole saliva was collected from healthy adults and plated to determine fungal carriage, and metal content was measured using ICP-mass spectrometry (ICP-MS).

Results: Zinc was most abundant, followed by iron, copper, manganese, and nickel. Cultivable oral Candida carriage was found in 48% of people. Total protein levels did not differ in salivas from donors with or without carriage. However, innate fungicidal activity was increased in donors with carriage; correlations between levels of several metals were stronger in salivas with fungal carriage, indicating a shift in the oral environment. Concentrations of copper and manganese, as well as age and gender, were significantly predictive of carriage levels in a multiple regression model.

Conclusions: Salivary copper and manganese content along with age and gender could be used as a predictive metric for individuals that are more susceptible to Candida overgrowth.

Infection Transmission by Saliva and the Paradoxical Protective Role of Saliva

Saliva is produced by both major (parotid and submandibular and sublingual) and minor (located in the mouth) glands, with different constituents and properties between the two groups. In the mouth saliva is a colorless, odorless, tasteless, watery liquid containing 99% water and 1% organic and inorganic substances and dissolved gases, mainly oxygen and carbon dioxide. Salivary constituents can be grouped into proteins (e.g., amylase and lysozyme), organic molecules (e.g., urea, lipids, and glucose mainly), and electrolytes (e.g., sodium, calcium, chlorine, and phosphates). Cellular elements such as epithelial cells, leukocytes and various hormones, and vitamins have also been detected. The composition of saliva is modified, depending on factors such as secreted amount, circadian rhythm, duration and nature of stimuli, diet, and medication intake, among others.

Essential and Toxic Metals in Oral Fluid-a Potential Role in the Diagnosis of Periodontal Diseases

Recently, many studies have investigated the relationship between the level of metals in the body and various diseases. The objective of this study was to examine any possible influence of periodontal disease upon the concentration of metals in oral fluid and blood and to explore the usability of applying cluster analysis coupled with the analysis of selected elements in oral fluid, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), cadmium (Cd) and lead (Pb), for effectively distinguishing people affected by periodontitis from healthy individuals. The quantification of eight metals in oral fluid and blood samples was performed by two inductively coupled plasma techniques-inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Most of the examined elements were detected at elevated concentration in the oral fluid of periodontal patients. However, the differences were statistically significant in the case of three metals: Cu, Mg and Mn (p < 0.05). Approximately, fivefold increase in the concentration of Cu, threefold-elevated levels of Mn and a twofold increase in the concentration of Mg were found in the oral fluid of the periodontal patients compared to the controls. Cluster analysis confirmed the statistical significance of the differences in the level of metals in the oral fluid between the two groups in most cases, plus enabled the correct classification of the subjects into patients and controls. The relationship between concentrations of metals and periodontal disease may in the future serve to prevent the development of such disease.

Trace metal levels in serum and urine of a population in southern Brazil

This study aimed to evaluate serum and urine concentrations of several trace metals of a non-directly exposed population in southern Brazil and establish reference values. Serum and urine samples were obtained from 240 volunteers (175 males and 65 females, age ranging from 18 to 74 years old). Levels of arsenic, chromium, cobalt, copper, lead, nickel, manganese and zinc were determined by means of dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS). Comparison between genders resulted in no significant difference for all metals but serum copper, as concentrations are higher in females than males. For most metals assessed, a negative correlation between serum concentrations and age was found, but no significant correlation was found between urine concentrations and age.

Age and Smoking Related Changes in Metal Ion Levels in Human Lens: Implications for Cataract Formation

Age-related cataract formation is the primary cause of blindness worldwide and although treatable by surgical removal of the lens the majority of sufferers have neither the finances nor access to the medical facilities required. Therefore, a better understanding of the pathogenesis of cataract may identify new therapeutic targets to prevent or slow its progression. Cataract incidence is strongly correlated with age and cigarette smoking, factors that are often associated with accumulation of metal ions in other tissues. Therefore this study evaluated the age-related changes in 14 metal ions in 32 post mortem human lenses without known cataract from donors of 11 to 82 years of age by inductively coupled plasma mass spectrometry; smoking-related changes in 10 smokers verses 14 non-smokers were also analysed. A significant age-related increase in selenium and decrease in copper ions was observed for the first time in the lens tissue, where cadmium ion levels were also increased as has been seen previously. Aluminium and vanadium ions were found to be increased in smokers compared to non-smokers (an analysis that has only been carried out before in lenses with cataract). These changes in metal ions, i.e. that occur as a consequence of normal ageing and of smoking, could contribute to cataract formation via induction of oxidative stress pathways, modulation of extracellular matrix structure/function and cellular toxicity. Thus, this study has identified novel changes in metal ions in human lens that could potentially drive the pathology of cataract formation.

Assessment of toxic metals in groundwater and saliva in an arsenic affected area of West Bengal, India: A pilot scale study

Communities in many parts of the world are unintentionally exposed to arsenic (As) and other toxic metals through ingestion of local drinking water and foods. The concentrations of individual toxic metals often exceed their guidelines in drinking water but the health risks associated with such multiple-metal exposures have yet to receive much attention. This study examines the co-occurrence of toxic metals in groundwater samples collected from As-rich areas of Nadia district, West Bengal, India. Arsenic in groundwater (range: 12-1064 µg L(-1); mean ± S.D: 329±294 µg L(-1)) was the most important contaminant with concentrations well above the WHO guideline of 10 µg L(-1). Another important toxic metal in the study area was manganese (Mn) with average concentration of 202±153 µg L(-1), range of 18-604 µg L(-1). The average concentrations (µg L(-1)) of other elements in groundwater were: Cr (5.6±5.9), Mo (3.5±2.1), Ni (8.3±8.7), Pb (2.9±1.3), Ba (119±43), Zn (56±40), Se (0.60±0.33), U (0.50±0.74). Saliva collected from the male participants of the area had mean concentrations of 6.3±7.0 µg As L(-1) (0.70-29 µg L(-1)), 5.4±5.5 µg Mn L(-1) (0.69-22 µg L(-1)), 2.6±3.1 µg Ni L(-1) (0.15-13 µg L(-1)), 0.78±1.0µg Cr L(-1) (<DL-5.9 µg L(-1)), 0.94±0.90 µg Pb L(-1) (<DL-4.2 µg L(-1)), 0.56±0.37 µg Se L(-1) (0.11-1.5 µg L(-1)) and 194±54 µg Zn L(-1) (112-369 µg L(-1)). The high concentrations of salivary As and Mn are believed to be indicative of intake from the groundwater. The clustering of salivary As and Mn in principal component analysis further indicated influence of the common exposure source. Zinc and selenium comprised a separate component presumably reflecting the local deficiencies in intakes of these essential elements from drinking water and foodstuff. Thus the study reveals that the concentration of other metals beside As must be monitored in drinking water before implementation of any policies to provide safe water to the affected communities.

Saliva as the Sole Nutritional Source in the Development of Multispecies Communities in Dental Plaque

Dental plaque is a polymicrobial biofilm that forms on the surfaces of teeth and, if inadequately controlled, can lead to dental caries or periodontitis. Nutrient availability is the fundamental limiting factor for the formation of dental plaque, and for its ability to generate acid and erode dental enamel. Nutrient availability is also critical for bacteria to grow in subgingival biofilms and to initiate periodontitis. Over the early stages of dental plaque formation, micro-organisms acquire nutrients by breaking down complex salivary substrates such as mucins and other glycoproteins. Once dental plaque matures, dietary carbohydrates become more important for supragingival dental plaque, and gingival crevicular fluid forms the major nutrient source for subgingival microorganisms. Many species of oral bacteria do not grow in laboratory monocultures when saliva is the sole nutrient source, and it is now clear that intermicrobial interactions are critical for the development of dental plaque. This chapter aims to provide an overview of the key metabolic requirements of some well-characterized oral bacteria, and the nutrient webs that promote the growth of multispecies communities and underpin the pathogenicity of dental plaque for both dental caries and periodontitis.

Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples

Human biomonitoring has become an important tool for the assessment of internal doses of metallic and metalloid elements. These elements are of great significance because of their toxic properties and wide distribution in environmental compartments. Although blood and urine are the most used and accepted matrices for human biomonitoring, other non-conventional samples (saliva, placenta, meconium, hair, nails, teeth, breast milk) may have practical advantages and would provide additional information on health risk. Nevertheless, the analysis of these compounds in biological matrices other than blood and urine has not yet been accepted as a useful tool for biomonitoring. The validation of analytical procedures is absolutely necessary for a proper implementation of non-conventional samples in biomonitoring programs. However, the lack of reliable and useful analytical methodologies to assess exposure to metallic elements, and the potential interference of external contamination and variation in biological features of non-conventional samples are important limitations for setting health-based reference values. The influence of potential confounding factors on metallic concentration should always be considered. More research is needed to ascertain whether or not non-conventional matrices offer definitive advantages over the traditional samples and to broaden the available database for establishing worldwide accepted reference values in non-exposed populations.

Noninvasive biomarkers of manganese exposure and neuropsychological effects in environmentally exposed adults in Brazil

Manganese (Mn), an essential element to humans, in excess can cause neurotoxic damage. So far, Mn exposure assessment has no ideal biomarker. This study aims to investigate the association between Mn exposure, using noninvasive biomarkers, and neuropsychological effects in environmentally exposed adults. The residents of two communities near to a ferromanganese refinery in Bahia, Brazil were evaluated. Volunteers aged 15-55 of both sexes provided scalp hair, axillary hair, fingernail and saliva specimens for Mn determination by electrothermal absorption spectrometry. Several neuropsychological tests were used to evaluate cognitive, attention, memory, motor and executive functions. Significant correlations were observed between Mn in hair (MnH, median 8.95 μg/g), axillary hair (MnAxH,18.49 μg/g) and fingernail (MnFN, 6.91 μg/g) with the performances in several neuropsychological tests. No association was observed between manganese levels in saliva (MnSal, 4.2 μg/L) and any neuropsychological function. Multiple regression analysis detected an inverse association between Log MnH and IQ (β=-4.76 [CI 95% -9.17 to -0.36]) and between Log MnFN and visual working memory (β=-3.33 [CI 95% -6.15 to -0.52]). Direct association was observed between Log MnFN and time of completion in the cognitive flexibility task (β=56.29 [CI 95% 2.41-110.18]). The Mn biomonitoring using noninvasive biomarkers was able to detect high exposure levels, which were associated with detrimental neuropsychological effects in adults exposed to industrial emissions.

Simultaneous determination of chromium, cadmium, and lead and evaluation of the correlation between chromium and cotinine in Chinese smokers

Heavy metals in tobacco caused wide public concern. To study the impact of heavy metals in smokers, 193 smokers and 58 nonsmokers were surveyed, and their urinary levels of chromium (UCr), lead (UPb), and cadmium (UCd) were assayed. In this study, UCr, UPb, and UCd in smokers (33.41 ± 14.99, 3.21 ± 1.34, 0.38 ± 0.64 μg/24 h, respectively) and nonsmokers (27.45 ± 10.49, 3.02 ± 0.88, 0.20 ± 0.16 μg/24 h, respectively) were determined by inductively coupled plasma mass spectrometry. The results showed that the content of UCr, UPb, and UCd in smokers were higher than in nonsmokers. Further analyses of correlations between the levels of urinary chromium and cotinine revealed positive relationship (correlation coefficient r = 0.51).

Zinc in the mouth, its interactions with dental enamel and possible effects on caries; a review of the literature

Zinc is an essential trace element. In the mouth, it is present naturally in plaque, saliva and enamel. Zinc is formulated into oral health products to control plaque, reduce malodour and inhibit calculus formation. It has good oral substantivity, and elevated concentrations can persist for many hours in plaque and saliva following delivery from mouthrinses and toothpastes. Although low concentrations of zinc can both reduce enamel demineralisation and modify remineralisation, during caries clinical trials, the addition of zinc to fluoride toothpastes has not affected their ability to reduce caries. Mechanistic studies may help explain this apparent contradiction. Zinc is readily desorbed from hydroxyapatite by calcium, which is plentiful in plaque and saliva. Where crystal-growth sites remain occupied by zinc despite this, they may simply be 'over-grown' by remineralisation initiated at unoccupied sites. Further, under certain conditions, low concentrations of zinc can enhance remineralisation of enamel lesions, by retarding lesion arrestment. Although this may help to explain the apparent lack of an overall zinc effect on caries, it seems unlikely that any negative effects would be countered exactly by positive effects. Further mechanistic studies, complementing well-designed in vitro and in situ caries studies, should lead to further understanding of the zinc-enamel interactions relevant to demineralisation and remineralisation.