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

SUMMARY: The study evaluated if men and women with severe tooth wear were at increased risk of general bone loss. Enamel biopsies obtained from 50 subjects aged 47.5 ± 5 years showed decreased copper content, which was associated with reduced spine bone mineral density, suggesting deficits of this trace element contributing to bone demineralization, enamel attrition, and deteriorated quality of mineralized tissues. INTRODUCTION: The objective of this cross-sectional study was to assess associations between enamel trace minerals and bone mineral density (BMD) in severe tooth wear. We hypothesized that similar factors contributed to both the excessive abrasion of dental enamel and reduced BMD in subjects with tooth wear. METHODS: Fifty patients aged 47.5 ± 5 years with severe tooth wear and 20 age-, sex-, and body mass index (BMI)-matched healthy volunteers with normal dental status were studied regarding dietary intakes of trace elements, serum and salivary copper (Cu), zinc (Zn), and calcium (Ca) concentrations, and serum PTH, osteocalcin, and hydroxyvitamin D levels. Tooth wear was determined using clinical examination based on standard protocol according to Smith and Knight. In all subjects, acid biopsies of the maxillary central incisors were carried out to assess mineral composition of the enamel. Atomic absorption spectroscopy with an air/acetylene flame was used to measure Ca and Zn, and graphite furnace atomic absorption spectroscopy was used to analyze Cu content. BMD was examined using dual energy X-ray absorptiometry. RESULTS: Tooth wear patients had reduced lumbar spine, but not femoral, BMD relative to controls (p < 0.001). No differences were found in enamel Ca concentration and Zn content was slightly higher in tooth wear patients than in controls whereas Cu content was significantly decreased in the patients: 19.59 ± 16.4 vs 36.86 ± 26.1 μg/l (p = 0.01) despite similar levels of Cu in serum and saliva. The differences were independent of serum 25-OH-D, osteocalcin concentrations or PTH either. CONCLUSION: Severe tooth wear is associated with reduced spinal BMD. Enamel in adult individuals with severe tooth wear is low in copper content. Therefore, further work is needed to determine whether copper plays a role in bone pathophysiology in these patients

The evaluation of zinc and copper content in tooth enamel without any pathological changes &ndash; an in vitro study

Elzbieta Klimuszko,1 Karolina Orywal,2 Teresa Sierpinska,1 Jarosław Sidun,3 Maria Golebiewska1 1Department of Prosthetic Dentistry, Medical University of Bialystok, Bialystok, Poland; 2Laboratory of Biochemical Diagnostics Department, Medical University of Bialystok, Bialystok, Poland; 3Department of Materials Science and Biomedical Engineering, Bialystok University of Technology, Bialystok, Poland Objectives: The objectives of the study were to evaluate the content of copper and zinc in individual layers of tooth enamel and to analyze the relationships between the study minerals in individual layers of tooth enamel. Patients and methods: Fifteen human permanent teeth were cut off every 150 &micro;m alongside the labial surface. Acid biopsy of each layer was performed. The zinc content was determined using the air&ndash;acetylene flame method. The copper content was determined using the electrothermal technique with argon. Results: The mean zinc concentrations increased significantly starting from the outer enamel surface, with the maximum concentration in the 150&ndash;300 &micro;m layer. The mean copper concentrations increased substantially from the outer enamel surface to a depth of 150 &micro;m, and then a slight downward trend of this mineral levels was seen, down to a depth of 450 &micro;m. Strong positive correlation was found between the zinc and copper concentrations at depths of 150&ndash;300, 450&ndash;600 and 600&ndash;750 &micro;m. Conclusion: The levels of zinc and copper in the outer enamel layers may have an effect on the increased content of unipolar minerals at deeper enamel layers. The content of the study elements determined may reflect the process of mineralization and maturation of enamel in the pre-eruption period. Keywords: zinc, copper, ename