By Antony Gitonga

A common joke in Naivasha is that one can tell who hails from there, from the colour of their teeth.

Why? With the high level of fluoride in water consumed in the lakeside town, dental fluorosis, or the browning of teeth, has affected nearly half of the population.

Fluorosis is an irreversible condition that can lead to permanent damage to the teeth and bone formation.

In its milder form, fluorosis appears as tiny specks that are often unnoticeable. In its severest form, which is also called mottling of dental enamel, it is characterised by black and brown stains, as well as cracking of the teeth.

The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, as well as other factors, such as nutrition.

The recommended level of fluoride in water, according to World Health Organisation, is 0.5 to 1.0 milligrams per litre (mg/L). Yet in some parts of Naivasha, the fluoride level is 25 times more at 12mg/L, hence the hundreds of cases of fluorosis.

According to some medics, the water drunk in Naivasha is not healthy for livestock, leave alone human consumption.

Statistics from the Naivasha District Hospital paint a grim picture, with 95 per cent of the patients in the Dental Unit suffering from fluorosis.

According to the hospital’s dental surgeon, Dr Jane Murugi, they attend to over 700 patients monthly.

Weak Enamel

"Fluorosis problem in Naivasha is very serious and we have noticed that it is caused by the water used for drinking," Murugi says, adding the age of the patients range from eight years to adulthood.

The doctor says that when fluoride goes to bones and the teeth, the enamel does not grow as it should, leaving it very weak.

Her sentiments are echoed by Dr Ndunu Chege, another dentist based in Naivasha.

Ndunu says he attends to about eight cases every week, all related to fluorosis.

"High levels of fluoride do not only affect the teeth, but also leaves bones very weak and prone to fracture," Chege says.

So serious is the problem, he says, it also affects self-esteem among youths who cannot smile in public.

Chege recalls a case of a teenage girl who dropped out of school after teasing from her peers on account of the colouring of her teeth.

"The classmates called her ‘brownie’ due to the colour of her teeth and she became withdrawn as she didn’t want to mingle with her classmates due to the ridicule," Chege says, adding that the process of repairing fluorosis is expensive and few people can afford it.

According to the doctor, temporarily masking coloured tooth costs around Sh1,700.

Unbothered Men

"For those seeking a permanent fix, they go for crowning, which costs Sh5,000."

Ndunu adds that the majority of his patients are girls and young women.

"It appears men are not bothered about the condition," he chuckles.

Although dental fluorosis is permanent and cannot be reversed, there are ways of concealing the damage. Treatment depends on the severity of the damage. When fluorosis is mild, the common approach is to sand off the layer of the enamel, a process known as abrasion.

In other instances, Ndunu says, composite bonding is done to change the damaged enamel to match the colour of the teeth. In severe cases, porcelain veneers are used to cover the surface of the teeth that have been damaged, but this is an expensive option.

During the recent army recruitment exercise in Naivasha, 70 per cent of the youths were rejected due to the nature of their teeth.

According to councillor Simon Wanyoike Wanango, the youth were denied a chance to serve their country for a problem that is way above them.

"Out of ten people in Naivasha, six people have a problem with their teeth and it’s unfair to have sent home these youths because of their teeth," he says.

The Lakeview ward councillor admits fluorosis is a major problem that requires joint initiative of the Government and donors to tackle.