The most common cause of brown teeth in this part of the world is,
DENTAL FLUOROSIS. This results from consuming high levels of fluoride in early childhood - a time when the permanent teeth are still developing inside the bone of the child. During the normal development of teeth, minerals such as calcium and phosphates are taken up by the tooth from the blood to form enamel and dentine. Other minerals such as sodium, potassium, magnesium and fluoride are taken up in much smaller quantities. A combination of these minerals in their right concentrations within the enamel and dentine gives the tooth its normal characteristics. When fluoride is in excess in the body, it is taken up by the developing tooth, causing other minerals not to be absorbed in their right quantities. This makes the overall mineral content lower. Such teeth usually grow with a normal appearance or an overly chalky-white look, then with time turn brown because of the porous nature of such teeth, which tend to pick up stain from the food and drink we consume.
Fluoride is a mineral found in the soil and in water. The levels vary depending on soil type and composition in a given area. For example in areas with volcanic soil, levels tend to be very high, and hence the ground water in such areas will also have high fluoride. Since the soil has high fluoride, any food grown in such soil will also take up and have excessive fluoride. Areas in the Rift Valley of Kenya tend to have the highest fluoride levels, as well as parts of Central Kenya
Excessive fluoride usually affects permanent teeth at the stage where they are developing within the bone before eruption- between ages 3 months to 6 years. If your siblings moved to a high fluoride area after this age, then they will likely not suffer from dental fluorosis.
The fluoride in toothpaste is actually good for your teeth as it strengthens them against tooth decay. Your dentist may even apply fluoride on your teeth if you are prone to tooth decay. The optimal level of fluoride in drinking water is also good for teeth and bones.
Firstly it is important to test your drinking/cooking water for fluoride levels especially if using borehole water or living in a high-fluoride area. Levels above 1.5mg/L are considered excessive. Excess fluoride in water can be reduced by use of special de-fluoridation filters. The ordinary commercial water filters do not remove excess fluoride. See http://cdnwaterquality.co.ke/ for more information on fluoride filters.
Yes, there is treatment for dental fluorosis. The severity of the condition will determine treatment.
MILD MODERATE MODERATE SEVERE
Finally it is important to prevent fluorosis where possible by avoiding the consumption of high fluoride. Where the condition is already established, please visit your dentist for review to discuss your options for restoring a beautiful, healthy smile.