Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcification may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Biomineralization). Signs and symptoms Calcification can manifest itself in many ways in the body depending on the location. In the pulpal structure of a tooth, calcification often presents asymptomatically, and is diagnosed as an incidental finding during radiographic interpretation. Individual teeth with calcified pulp will typically respond negatively to vitality testing; teeth with calcified pulp often lack sensation of pain, pressure, and temperature. Causes of soft tissue calcification Calcification of soft tissue (arteries, cartilage, heart valves, etc.) can be caused by vitamin K2 deficiency or by poor calcium absorption due to a high calcium/vitamin D ratio. This can occur with or without a mineral imbalance. A common misconception is that calcification is caused by excess amount of calcium in diet. Dietary calcium intake is not associated with accumulation of calcium in soft tissue, and calcification occurs irrespective of the amount of calcium intake. Intake of excessive vitamin D can cause vitamin D poisoning and excessive intake of calcium from the intestine, when accompanied by a deficiency of vitamin K (perhaps induced by an anticoagulant) can result in calcification of arteries and other soft tissue. Such metastatic soft tissue calcification is mainly in tissues containing "calcium catchers" such as elastic fibres or mucopolysaccharides. These tissues especially include the lungs (pumice lung) and the aorta. Mineral balance Dystrophic calcification, without a systemic mineral imbalance. Metastatic calcification, a systemic elevation of calcium levels in the blood and all tissues. Forms Calcification can be pathological or a standard part of the aging process. Nearly all adults show calcification of the pineal gland. Location Extraskeletal calcification, e.g. calciphylaxis Brain, e.g. primary familial brain calcification (Fahr's syndrome) Choroid plexus usually in the lateral ventricles Tumor calcification Arthritic bone spurs Kidney stones Gall stones Heterotopic bone Tonsil stones Pulp stone Breast disease In a number of breast pathologies, calcium is often deposited at sites of cell death or in association secretions or hyalinized stroma, resulting in pathologic calcification. For example, small, irregular, linear