Dental fluorosis is a condition that causes discolouration or mottling of the teeth, giving them a permanent, brownish colour.

It not only affects teeth, but also bone structure and density, leading to defects and skeletal weakness. Whereas low levels of fluoride can help to strengthen teeth, excessively high levels can be very damaging.

Fluorosis first attracted attention in the early 20th Century. Researchers were surprised by the high prevalence of what was called “Colorado Brown Stain” on the teeth of native-born residents of Colorado Springs, USA.

Further research discovered the stains were caused by naturally high levels of fluoride in the local water supply. It is caused by overexposure to fluoride during the first eight years of life.

This is the time when most permanent teeth are being formed. Locally, areas around Nakuru, Naivasha and Baringo have historically been known to have high fluoride levels in their water sources. This has since changed.

Many children in Kenya are at risk of fluorosis because of high levels of fluoride in their drinking water. In urban areas where population explosion has put a lot of pressure on fresh water sources like natural springs, home owners and developers are increasingly turning to borehole water for their supplies. This water, in some places, carries excessive and dangerous amounts of fluoride.

The risk is made worse by the fact that, as the rest of the world moves to treated and piped water systems, more than half of Kenyans (56 per cent) still rely on underground water, which the Kenya National Bureau of Statistics (KNBS) defines, among others, as water fetched from wells and boreholes.

Scientists say most of Kenya’s underground water contains fluoride levels that are higher than the 1.5 milligrammes per litre recommended by the World Health Organisation.

Data from Kenya Society for Fluoride Research further shows that 19 million Kenyans suffer from fluorosis, affecting the teeth and/or skeleton, depending on the length of time one has been exposed to water with a high concentration of fluoride, and their geographical location.

So when does the effect of fluorosis begin? It begins within the first six weeks of pregnancy when the teeth and bones are being formed in the womb.

White markings

When the baby’s teeth begin to show, those affected by fluorosis may appear mildly discoloured. For instance, there may be tiny white markings that only dentists can detect.

In more severe cases, however, the teeth may have stains ranging from yellow to dark brown, surface irregularities or pits that are highly noticeable.

The effects can be more severe where children can prematurely lose their teeth due to weakening.

There are other causes of fluorosis. For example, dental products like toothpaste or mouthwash that contain high amount of fluoride. Sometimes, children enjoy the taste of fluoridated toothpaste so much that they swallow it instead of spitting it out.

Another source are fluoride supplements taken during childhood. We cannot justify taking fluoride supplements or fluoride-fortified fruit juices and soft drinks when we already have fluoridated drinking water as we do in Kenya.

This may result in consumption more fluoride than is healthy. If one is considering taking these supplements, dental health professionals can advise if this is necessary.

So what’s the solution?

For expectant mothers (or those hoping to be soon), getting your drinking water tested should be the first step in preventing your child from the effects of fluorosis.

Mothers should limit their drinking of bottled water to those that indicate a safe level of fluoride. Alternatively, one can run water across activated alumina-Aluminium oxide, which captures the fluoride, or drink distilled water.

Other alternatives include the installation of water purifiers in cases where the primary source of water is a borehole or a well. Although fluorosis is not a disease, its effects can be psychologically distressing and difficult to treat. There are a number of companies that offer water purification systems. At Kenya Orthodontics we use Pureflow Nairobi to make sure our water purification is just right.

Families are also advised to make regular visits to the dentist, at least twice a year, for observation and general dental care. If you notice that your child’s teeth have white streaks or spots or if you observe one or more discoloured teeth, contact a dentist.

If you suspect your child’s permanent teeth are not developing normally, seeing a specialist orthodontist is advisable for adequate and timely action. This is best done from the time the permanent teeth start to come through, at around six years of age.

Dr Wandia is a Specialist Orthodontist at Kenya Orthodontics