**5. Types of fluorosis in Yemeni regime**

Fluoride is one of the few chemicals that have been proven to have harmful effects on people when consumed through drinking water. Fluoride in drinking water has beneficial effects on teeth at low concentrations, but excessive exposure to fluoride in drinking water, alone or in combination with fluoride from other sources, can cause a variety of problems. As the level and duration of exposure increase, these range from mild dental fluorosis to crippling skeletal fluorosis.

The chemical characteristics of the drinking water from the study reflect high fluoride contamination above the permissible limits of Yemeni, and WHO standers and most of them are poor whoever, their nutritional status is expected to be very poor. These factors including the high concentration of Na- and HCO3 − and low concentration of Ca2+ions will increase the severity of fluorosis.

The visual observations in some selected Yemeni villages identify that there are two types of fluorosis recognized, they are:

#### **5.1 Dental fluorosis**

Mottling of teeth is one of the most easily recognized symptoms from different Yemeni governorates especially Taiz and Al Dhalla. The teeth of the children in the affected areas lose their normal creamy white translucent color and become rough, opaque, and chalky white. Some of the local inhabitants indicated that their teeth have be extracted and replaced with dentures. The dental fluorosis ranges from mild to severe fluorosis. The photographs represent some of dental fluorosis from the different areas in Yemen. High percentage dental fluorosis among the children has been observed in Taiz and Al-Dhala basins (**Figure 3A** and **B**).

Dental fluorosis is the most common fluoride ailment identified in the afflicted areas, according to visual observations from selected villages. Fluorosis in the teeth can range from mild to severe.

In general, there is a link between fluoride in the water and the occurrence of dental fluorosis in the Taiz and Al-Dhala regions. A published research paper concluded that there is a positive relationship between fluoride in water and the occurrence of dental fluorosis in Sanhan, Taiz, and Al-Dhala regions [7]**.**

#### **Figure 3.**

*Figures present severe dental fluorosis (A) and moderate dental fluorosis (B) in Yemeni children in the affected area, after Alamry (2009) [7]***.**

*Origin and Hydrogeochemistry of Fluoride in the Context of the Yemen Regime DOI: http://dx.doi.org/10.5772/intechopen.104255*

**Figure 4.** *A group of children showing skeletal deformation from Al-Dhalla region Yemen.*

## **5.2 Skeletal fluorosis**

Fluorapatite is 1000 times less soluble than hydroxyapatite, the most common mineral found in bone. The F− ion aggressively substitutes for the OH− ion, resulting in an accumulation of F− in bone tissue and skeletal fluorosis [20]**.**

The patient often complains of a vague discomfort in the limbs and trunk early on in the development of fluorotic changes in the skeleton. Back pain and stiffness, particularly in the lumbar region, follow. Fluorosis in the teeth is frequently visible with the naked eye and is easy to detect even by laypeople. On the other hand, even with the assistance of appropriate equipment, skeletal fluorosis and nonskeletal fluorosis are difficult to diagnose. Radiography is frequently used to detect symptoms such as joint enlargements or minor bone deformations.

There are no any publications presenting the problem of the skeletal fluorosis among children in the affected Yemeni places, while I have seen children in Al-Dhalla villages showing skeletal deformation, and these cases among children could be considered as cases of skeletal fluorosis unless proved otherwise, as it is shown in **Figure 4**.
