aging

Gum Disease More Common With Old Age

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A recent study which appeared in Nature Immunology shows that the deterioration in gum health which occurs with increasing age is associated with a drop in the level of a chemical called Del-1. Periodontitis is a disease of the gums which causes bleeding and bone loss which can, over time, lead to loss of teeth. Periodontitis  is caused by an over-active immune response to bacteria that grow in the mouth. As people age they are more likely to suffer from inflammatory diseases, including gum disease. The new research investigated gum disease in young and old mice and found that an increase in gum disease in the older animals was accompanied by a drop in the level of Del-1. Del-1 is known to restrain the immune system by stopping white blood cells from sticking to and attacking mouth tissue. In mice that had … Read more

Aging Causes Fracture Toughness Reduction in Dentin

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Researchers led by Dr. Dwayne D. Arola of the University of Maryland, have recently examined the role of aging and its affect on the reduction in fracture toughness of human dentin. The article appears on the Journal of the Mechanical Behavior of Biomedical Materials (October 2009 issue, pages 550-559). Dr. Arola and colleagues found that the average fracture toughness of  old dentin was approximately 30% lower than young dentin. The researchers observed that the fracture toughness seemed to depend on the number of lumens, which is important in determining the mineral-to-collagen ratio and the variation in the degree of age-related sclerosis, or embrittlement, throughout dentin. They were able to do this by examining the crack growth resistance of human coronal dentin using tissue obtained from patients 18 to 83 years of age and for crack extension oriented perpendicular to the … Read more