ABSTRACT
Drinking water can contain fluoride which is effective in preventing dental caries at concentration of ≤1.5 mg/L however at concentrations ≥1.5 mg/L, it could lead to dental fluorosis. Dental fluorosis is a disorder that occurs due to excessive fluoride intake during the mineralization of the teeth, resulting in an uneven distribution of brown and yellow coloration. I assessed fluoride levels in 19 samples of natural water sources (such as boreholes, streams, and wells) and commercial drinking water sources (such as sachet and bottled water products) in Zing Local Government Area, Taraba State, northeastern Nigeria, I then determined the prevalence of dental fluorosis in 135 children, aged 10 to 17 years, who were born in Zing. Using cross tabulations and logistic regression modelling, I evaluated factors that might influence whether a child had dental fluorosis, such as dental care habits and drinking water source. Fluorosis occurred in 111 respondents. Fluoride levels exceeded the World Health Organization permissible limit of 1.0mg/L for tropical environments in most borehole samples, while most stream and well samples did not exceed this limit. The regression model showed that odds of a child having dental fluorosis were higher for
vii
those children who drank borehole water compared to those who do not (OR = 8.522), while the odds of having fluorosis decreases for children who drink from stream water (OR = 0.203). Consequently, community boreholes may need to be de-fluoridated and there should be community awareness about the sources of water with high fluoride concentrations.
Keywords: Boreholes, dental fluorosis, drinking water, fluoride, Nigeria, streams, wells
viii
TABLE OF CONTENTS
CERTIFICATION PAGE ……………………………………………………………………………..ii
APPROVAL PAGE …………………………………………………………………………………….iii
DEDICATION…………………………………………………………………………………………….iv
ACKNOWLEDGEMENTS …………………………………………………………………………..v
ABSTRACT……………………………………………………………………………………………….vi
TABLE OF CONTENTS …………………………………………………………………………..viii
LIST OF TABLES ……………………………………………………………………………………….x
LIST OF FIGURES …………………………………………………………………………………….xi
LIST OF ABBREVIATIONS………………………………………………………………………xii
CHAPTER 1 ………………………………………………………………………………………………..1
INTRODUCTION…………………………………………………………………………………………1
Signs of Dental Fluorosis……………………………………………………………………11
Sources of Fluoride in the Environment and Human Body …………………….11
Stages of Dental Fluorosis…………………………………………………………….21
Dental Fluorosis Correction………………………………………………………………..22
Methods of Water De-fluoridation….…….…………….…………………..23
HYPOTHESES………..………….…………………………….………………….25
AIMS AND OBJECTIVES…………………………………………………………………………..25
CHAPTER 2……………………………………………………………………………………………….26
MATERIALS AND METHODS ………………………………………………………………….26
Study Area ………………………………………………………………………………………26
Data Collection and Analysis ……………………………………………………………..26
Ethical Guidelines……………………………………………………………………….……31
CHAPTER 3 ……………………………………………………………………………………………….32
RESULTS…………………………………………………………………………………………………..32
CHAPTER 4 ……………………………………………………………………………………………….39
DISCUSSION………………………………………………………………………………………………39
Limitations of Study ………………………………………………………………………….42
Challenges………………………………………………………………………………………..43
Recommendations …………………………………………………………………………….43
CHAPTER 5 ………………………………………………………………………………………………44
ix
CONCLUSION …………………………………………………………………………………………..44
APPENDIX I ………………………………………………………………………………………………45
APPENDIX II………………………………………………………………………46
REFERENCES…………….……………………………………………………….48
x
LIST OF TABLES
Table 1. Prevalence of dental fluorosis in Estonia in respect to different concentrations of fluoride in drinking water………………………………………………………….7
Table 2. Fluoride concentration is several water sources studied across different countries……………………………………………………………………..….…….8
Table 3. Fluoride content and percentage of fluoride extracted in tea plants (extraction time)…………………………………………………………………………………..17
Table 4. Level of fluorosis according to Dean’s dental fluorosis index………………..21
Table 5. Number of water samples collected from different sources of water in each ward…………………………………………………………………………….28
Table 6. Frequencies of drinking water sources used by children in Zing LGA……..33
Table 7. Fluoride concentration in various water sources tested across different wards…………………………………………………………………..……………34
Table 8. Relationship between predictor variables measured in this study and the presence of dental fluorosis in children in Zing LGA…………………………….…35
Table 9. Frequencies of cases of dental fluorosis in relation to the ward where a child was born.…………………………………………………………………………… 36
Table 10. Likelihood-ratio estimates of logistic-regression parameters for the best-fit model……………………………………………………………………………..….37
xi
LIST OF FIGURES
Figure 1. Countries with endemic dental fluorosis due to excess fluoride in drinking water……………………………………………………………………..………….…8
Figure 2. Sources of drinking water in Nigeria………………………………………..9
Figure 3. Different local governments across the geopolitical zones in Nigeria where fluoride in drinking water exceeds 0.8ppm………………………………..…..….….10
Figure 4. Fluoride cycle……………………………………………….…………….12
Figure 5. Different stages of fluorosis…………………………….………….………22
Figure 6. Location of Taraba State in Nigeria and location of Zing LGA (far northeast) in Taraba State………………………………………………………………..……….27
xii
LIST OF ABBREVIATIONS
WHO – World Health Organization
UNICEF – United Nations Children Fund
ppm – Parts per million
mg/L – Milligram per liter
mg/kg – Milligram per kilogram
km – Kilometer
F+ – Fluorine ion
1
CHAPTER 1
INTRODUCTION
Water is a very important basic requirement for human life and that is why water quality is an important factor and a key area of concentration in public health. Fluoride, is an important element considered to be beneficial at low concentrations and toxic at high concentrations when present in water. Fluoride is toxic as a result of its strong affinity for calcium, this gives it the ability to react with structures that are made of calcium such as teeth and bones. The World Health Organization (WHO) guideline for permissible fluoride concentration in drinking water is set at 1.5 mg/L (WHO, 2011). However, the WHO has emphasized the need for national authorities to set national fluoride standards taking into consideration climatic condition, fluoride intake from alternative sources, and daily water intake (Lennon, Whelton, O’Mullane, & Ekstrand, 2005).
Common techniques used to detect fluoride levels include fluoride ion selective electrode method, calorimetric methods, ion chromatography methods, and use of photometer (Agency for Toxic Substances and Disease Registry, 2001).
For many years, there has been a global public health debate about both the beneficial and adverse effects of fluoride in water sources (UNICEF, 1999). This debate first came about in the 1930s and 1940s when a study revealed that fluoride concentrations below 1.5 mg/L in water is effective in preventing tooth decay, otherwise known as dental caries (Dean & Brandt Jr, 1974). According to jones et al. (2005), dental caries affects approximately 60-90% of school children in most
2
developed countries. In addition, Jones et al. (2005) also identified Latin American and Asia as the continents with the highest prevalence of dental caries.
According to Gussy et al. (2008), fluoride provides protection to the teeth in two ways; pre and post eruption. The pre-tooth eruption occurs while the tooth is still developing. Dental tissues, especially the enamel, are incorporated with fluoride giving them the ability to resist de-mineralization. The post-eruptive stage occurs when there is topical contact between the fluoride and erupted teeth enhances the ability of the teeth to replace surface minerals on the teeth. In addition, jones et al. (2005) highlighted that fluoride improves the chemical structure of the dental enamel and it also reduces the acid formation ability of plaque bacteria. All these properties further emphasized by gussy et al. (2008), makes fluoride an effective agent in preventing dental caries.
Despite the effectiveness of fluoride in combating dental caries, in high concentrations, fluoride could lead to a condition called dental fluorosis (Dean, 1934). Dental fluorosis, also referred to as Colorado brown stain, is a disorder that occurs during the mineralization of the teeth, resulting in an uneven distribution of brown and yellow coloration. McKay (1952) refers to dental fluorosis as the mottling of the enamel. The teeth appear opaque, disfigured, and discolored (Soto-Rojas et al., 2004). This defect occurs in children between the ages of 0 and 8 when the teeth is still developing (Beltran-Aguilar, Barker, & Dye, 2010).
Dean and Brandt Jr. (1974) were one of the first researchers to show the relationship between dental caries and dental fluorosis in respect to fluoride concentration in
3
community water. Their study showed that 4-5% of the 114 children in their study who drank from community water that had fluoride concentration of 0.6 – 1.5 ppm were dental caries free while 22-27% of the children who drank from community water of concentrations above 1.5 ppm were caries free and showed dental fluorosis. More studies have also shown the inverse relationship between dental fluorosis and dental caries. Marya et al. (2004) showed that in Haryana, India, as the level of fluoride rose from 0.5 – 1.13 ppm, the prevalence of dental caries reduced from 48.02% to 28.07% without very significant increase in prevalence of dental fluorosis. However, as fluoride concentrations continued to increase to 1.51 ppm, the prevalence of dental fluorosis increased as well (Marya et al., 2004).
In the last two decades, there has been a considerable reduction in the incidence of dental caries on the other hand, there has been reasonable increases in the number of cases of dental fluorosis (Buzalaf, Cury, & Whitford, 2001). These changes in the patterns of dental health are mainly due to the increased fluoridation of community water evident in countries like the United States, Australia (Fagin, 2008; Gussy et al., 2008). Research conducted in Australia showed that since the introduction of community water fluoridation, 90% of children (12 years of age) had experienced dental fluorosis. This number however, in 1994 had reduced to 42.5% and in 1999, it reduced to 35.5% (Gussy et al., 2008).
During the process of tooth formation, amelogenins: proteins that the build-up of hydroxyapatite crystals, are broken down and eliminated from the matured enamel after tooth development. When fluoride is ingested at higher concentrations than the normal, it interferes with tooth development causing amelogenins to remain in the
4
developing tooth longer than normal causing the crystalline structure of the enamel to be tampered with. When the enamel finally develops and erupts, the teeth is seen to have unevenly distribution of lines and color. At more severe situations, the teeth are pitted with brown or yellow coloration (Fagin, 2008). This is why dental fluorosis usually occurs in children (0-8 years) whose teeth are in the process of still developing. This results in an increased risk of having an aesthetic change or fluorosis in the permanent teeth when children are exposed to high levels of fluoride during this period (Alvarez, et al., 2009).
Dental fluorosis is a public health concern in places where the concentration of fluoride in water exceeds the prescribed levels (Soto-Rojas et al., 2004). Brown (2012) reports that 38% of children (15 years of age) in fluoridated Irish communities have shown signs of having dental fluorosis. Despite that dental fluorosis is mainly caused by naturally occurring fluoride in natural drinking water sources, it is also associated with wide use of fluoridated products, such as toothpaste, supplements, and nutrition (Akpata, Danfillo, Otoh, & Mafeni, 2009).
Many fluoridation programs have been implemented in several countries worldwide so as promote a decrease in dental caries. In some Latin American Countries, fluoridation of salt and water have been largely introduced (Jones et al., 2005). The total amount of fluoride obtained from other sources of consumption during tooth development contributes to the risk of having dental fluorosis (Buzalaf et al., 2001). The severity of dental fluorosis depends on the length of exposure to fluoride, response of the individual, nutritional factors, and physical activities. Some
5
researchers have also shown that living at high altitudes and climatic conditions also play a role in the prevalence of dental fluorosis (Soto-Rojas et al., 2004).
Climatic conditions also play a role in the prevalence of dental fluorosis in some regions. Although the WHO global recommendation for fluoride concentrations in water is ≤ 1.5 mg/L, the organization advises that permissible level is ≤ 1 mg/L in tropical regions (UNICEF, 1999). This is simply because in warmer climates, people perspire more and tend to drink more water, hence consuming more fluoride compared to people who live in temperate regions. In Africa, dental fluorosis has been associated with fluoride levels in natural drinking water sources as low as 0.1–0.4 mg/L (Akpata, 2014). In addition, research has shown that in southern parts of Ukraine where the climate is warmer than other parts of the country, fluorosis is evident at concentrations lower than 1.2 mg/L (Fordyce et al., 2007). Marya et al. (2014) suggested that in warm parts of the United States, fluoride content in water sources should range between 0.7 – 1.2 ppm.
Dental fluorosis is not a disease, but rather a defect hence various societies and cultures perceive it differently. It is considered to be an aesthetic problem because it changes the natural coloration of the teeth hence making individual with fluorosed teeth feel embarrassed by this condition. The smile greatly affects people’s view on attractiveness, it plays a role in a person’s confidence and self-esteem (Hassebrauck, 1998, as cited in Molina-Frechero, et al., 2017). In Brazil, there have been cases of people reported to be stigmatized and discriminated as result of the color of their teeth. These people were deprived of smiling and having a normal social life (Santa-Rosa et al., 2014). Brown (2012) conducted a study in order to determine the rate at
6
which individuals with fluorosed teeth perceive it as an aesthetic problem. The study revealed that cases categorized as “mild” or more were identified by the affected individuals as an aesthetic problem. Study conducted by Molina-Frechero et al (2017) in Durango city of Colorado showed that 68% of adolescent with dental fluorosis showed concern about the colour of their teeth. A study conducted in Palestine revealed that 87.5% of the 350 children with fluorosis studied do not accept the apearance of their teeth as a result of the colour, in addition, 99.7% of the children believe that the appearance of the teeth affects personality and aesthethic appearance (Abuhaloob & Abed, 2014).
Asides from dental fluorosis, high intake of fluoride leading into accumulation in bones can also result into skeletal fluorosis. This condition is characterized by joint pains and stiffness. Furthermore, much higher concentrations can cause atherosclerosis and other bone deformities. These conditions are very evident in communities such as the Rift Valley and in China where very high concentration of fluoride exists naturally in groundwater (WHO, 2010). Dan (2008) highlighted that the ability of fluoride to tamper with the crystalline structure of bone could lead to increased risks of fractures. Though there are few studies on this, fluoride intake has also been associated with hypersensitivity (Kaminsky, Mahoney, Leach, Melius, & Miller, 1990). Few studies have raised fears that fluoride could lead to proliferation of osteoblast cells (bone-building cells) and result into the formation of malignant tumors (Fagin, 2008). Sutton et al. (2012) suspects that exposure to high naturally occurring fluoride in water contributes to cardiovascular dysfunction. Animals who ingest these fluoride toxic substances also prone to fluorosis; fluoride toxicity is not
7
just harmful to human health but also affect animal husbandry, agricultural crops and plants in their natural habitat (Abugri & Pelig-Ba, 2011).
Research conducted by Indermitte et al. (2009) compared Estonia’s population exposure to different natural water sources with different fluoride concentrations and risk of dental fluorosis and the findings showed the increased risk of fluorosis in populations where the people were exposed to water with fluoride concentration higher than the WHO accepted value of 1.5 mg/L (Table 1).
Table 1. The prevalence of dental fluorosis in Estonia in respect to different concentrations of fluoride in natural drinking water sources. (Source: Indermitte, Saava, & Karro, 2009).
According to UNICEF (1999), dental fluorosis is endemic in more than 25 countries globally (Fig. 1), some of these countries affected globally include China, Japan, India, Kenya, Uganda and Mexico amongst others. In addition, UNICEF (1999) adds that dental fluorosis is endemic in 15 out of 32 states in India. Studies on dental fluorosis in relation to different concentrations of fluoride in drinking water have been conducted in various countries (Table 2).
8
Fig. 1. Countries with endemic dental fluorosis due to excess fluoride in drinking water (Source: UNICEF, 1999).
Table 2. Fluoride concentration is several water sources studied across different countries (Source: Lorna, Start, Dave, & Jamie, 2006).
9
Research conducted in Ghana and Tanzania showed that a good number of sources of water exceeded fluoride concentration of 20 ppm in central parts of Tanzania and 4 ppm in parts of Ghana. The water samples analyzed (23% and 57% in Ghana and Tanzania respectively) were all in excess of WHO permissible levels. Dental fluorosis is prevalent in these areas (Smedley et al., 2002).
In Nigeria, only a few studies have been conducted to determine the relationship between fluoride exposure and dental fluorosis. Akpata et al. (2009) conducted research so as to map out fluoride concentration in water sources that cut across Nigeria. From their findings, 62% of the 109 local governments had fluoride concentration of 0.3 ppm or less. Some water samples showed high fluoride content that exceeded 1.5 ppm and a certain well in their studies had maximum fluoride concentration of 6.7 ppm (Akpata et al., 2009).
Fig. 2.
Fig. 2. Sources of Sources of drinkingdrinking water in Nigeria (Source: Akpata et al., 2009).water in Nigeria (Source: Akpata et al., 2009).
10
Fig. 3. Different local governments across the geopolitical zones in Nigeria where fluoride in drinking water exceeds 0.8 ppm (Source: Akpata et al., 2009).
Dental fluorosis has been identified in many Nigerian cities, some of which include Abeokuta, Katsina, Maiduguri, and Yola (El Nadeef & Honkala, 1998). Water samples collected over different zones of Nigeria showed variations in fluoride content of water. In western Nigeria, water samples had between 0.0-0.4 ppm fluoride content. While in northern Nigeria, water samples tested between 0.0-1.2 ppm fluoride content (El Nadeef & Honkala, 1998). One of those researches conducted by El Nadeef and Honkala (1998) showed that in central Nigeria particularly Bauchi and Plateau states showed that fluoride concentrations detected were between 0.0-0.4 ppm and 51% of the subjects had dental fluorosis. Nigeria has a humid tropical climate where temperature ranges between 28-32ºC, this suggests in the results that temperature played a role (Akpata et al., 2009). Tropical regions where there is more daily water consumption often show dental fluorosis even at low concentrations of fluoride in drinking water. Despite that the WHO have set a
11
guideline of 1.5 ppm fluoride concentration in water, Brouwer et al. (2009) recommended a limit of 0.6 ppm fluoride concentration in drinking water in Senegal. In addition, Akpata et al. (2009) recommended a range of 0.3 – 0.6 ppm fluoride concentration in drinking water for a warm country like Nigeria. Drinking water in Nigeria is supervised by the Ministry of Health and it is responsible for ensuring that water consumed via different sources are up to required quality (Standard Organization of Nigeria, 2007)
Signs of Dental Fluorosis
The clinical symptoms as described by Cutress and Suckling (1990) are the presence of thin white lines observed across the surface of the teeth. These white lines are opaque and appear to align with the perikymata pattern. There may be complete opaqing of the incisal and cusps edges and the marginal ridges. In moderate fluorosis cases, the lines appear to be cloudy and unevenly scattered on the teeth surface. As the severity of the case increases, the whole teeth surface becomes opaque with some areas exhibiting brown/yellowish coloration (Cutress & Suckling, 1990).
Sources of Fluoride in the Environment and Human Body
There are several media through which fluoride gets circulated through the environment and human body. The diagram below was adopted by the World Health Organization to summarize several sources and means through which fluoride circulates the bio-geosphere. According to Bhat et al. (2015), there are two major channels that fluoride pollutes the environment: normal and anthropogenic. The major source of fluoride in the surface of the earth is rock minerals. This is the normal or in other words natural channel through which fluoride is exposed into the
12
environment. Another form of normal or natural channel is through volcano eruptions. Madison and Firehole rivers found at Yellowstone Park in the United States are geothermal areas where fluoride concentration ranges between 1 to 14 ppm. These regions with thermal waters such as New Zealand, Pyramid and walker lakes contain approximately 13 ppm fluoride concentration (Camargo, 2003).
Fig. 4. Fluoride circle. Fluoride circulation in the biosphere through various sources (Source: WHO, 2002).
Anthropogenic Factors
The anthropogenic channel is through human activities due to industrialization. The introduction of pesticides that contain fluoride have contributed to the presence of fluoride in soils and water surrounding water bodies. Burning of fossil fuels and motorization are also anthropogenic factors that have contributed to the presence of fluoride in the environment (Bhat et al., 2015). Studies in the Ukraine showed enhanced environmental concentrations of fluoride as a result of coal mining (Fordyce et al., 2007). Industries producing steel, zinc, fertilizers, glass and ceramic are sources of fluoride release into the environment (Bhat et al., 2015).
13
The development and the use of chemicals such as hydrogen fluoride (HF), fluorosilicic corrosive (H SiF), sulfur hexafluoride (SF), sodium fluoride (NaF), and phosphate composts (release fluoride into agricultural soils) have also become channels through which fluoride is released into the environment/human body (Bhat et al., 2015). The WHO (2010) revealed in their report that other channels through which fluoride gets into the environment is evident in large commercial laundries and semi-conductor industries who use hydrogen fluoride – which is very soluble in water and in fumigants made with sulfuryl fluoride.
In addition, WHO has added that in Canada and Netherlands, approximately 23,500 and 46,600 tons of fluoride are released to the environment via industrial sources (WHO, 2002). The Kitimat River and Sagueny River in Canada all contain approximately 10 times more fluoride concentration because aluminum smelters are situated close to these rivers (Camargo, 2003). According to Peterson et al. (2008), the coal burning in South-western China is the main cause of endemic dental fluorosis in the region. The coal burning in China has led to fluoride pollution in 14 Chinese provinces eventually leading to skeletal fluorosis and dental fluorosis suffered by 2.9 and 39 million people respectively in that those provinces (Peterson, Kwan, Zhu, Zhang, & Bian, 2008).
Studies by HanDong et al. (2011) in Guizhou China, showed that the cause of endemic fluorosis which include both dental and skeletal fluorosis alongside other deformities is as a result of coal burning. Fluorosis in this region is called coal-burning fluorosis (HanDong, Yanci, Joseph, Yatzor, & Ping, 2011).
14
Natural Fluoride in Water
Waters that are found naturally at rocky geographic locations are known to contain high fluoride content as a result of the mineral leaching from these rocks and mountains. Natural fluoride in water have often been associated to areas with high altitude due to presence of rocks and mountains. Studies conducted in Mexico, Kenya and Tanzania have shown that high prevalence of dental fluorosis is associated with high altitude (Soto-Rojas et al., 2004).
The Rift Valley in East Africa is known to have waters that contain high fluoride content naturally. Other geographical locations that are known to contain naturally very high fluoride content in their water include parts of Egypt, Algeria, Japan, Thailand and China among many others (O’Mullane et al., 2016). Due to the abundance of fluoride in the earth’s crust, waters are known to naturally contain fluoride in them just in different concentrations. Lakes and rivers are known to contain fluoride concentrations as low as 0.5 ppm and as high as 95 ppm (Recorded in Tanzania). A case study done in the Rift Valley revealed that Lake Nakuru contained the highest naturally existing fluoride concentration found to be 2800 ppm (O’Mullane et al., 2016).
High fluoride concentration occurring naturally in groundwater has become an area of concern. Countries such as Mexico, China, Argentina and India among many others are known to have high-fluoride containing groundwater. India, China and Mexico amongst these countries are estimated to have about 70, 45 and 5 million people suffering from severe endemic fluorosis respectively (Smedley et al., 2002). In addition, studies conducted in 19 Mexican states showed that 7 of those states
15
have naturally occurring high fluoride content in their drinking water (Soto-Rojas et al., 2004). Generally, fresh water that are not polluted contain fluoride content that range between 0.01 to 0.3 ppm meanwhile polluted salt waters contain fluoride content ranging between 1.2 to 1.5 ppm (Camargo, 2003)
Artificial Fluoridation of Water
The fluoridation of water has often been referred to a great achievement in the 20th century. This is largely because fluoridation of water has become effective in combating dental caries. The first community water fluoridation program was based in the United States in the year 1945. In the late 1960’s several states which include Indianapolis, Philadelphia, New York, San Francisco, Chicago, Detroit and Dallas implemented community water fluoridation (Jones et al., 2005). In the United States, two third of the general population drink water from water systems that are artificially fluoridated to combat dental caries. Despite its effectiveness, it has been argued to be a form of mass medication that is unethical (Gussy et al., 2008).
After the introduction of fluoridated water in the community, dental surgeons in the United States reported a dramatic 60% reduction in dental caries (Erdal & Buchanan, 2005). In 1998 in a paediatric clinic in Boston, in an area with fluoridated water, a study revealed that 69% of the children that were examined had dental fluorosis. Another research conducted in an area of North Carolina where the water is fluoridated showed that 78% prevalence of dental fluorosis while further researchers conducted in areas where there was almost no fluoridation of water showed a prevalence of 3-45% (Erdal & Buchanan, 2005).
16
Food
Fluoride may be present in various foods consumed by humans. Studies in Canada showed mean fluoride concentrations of 2.118 mg/kg in fish and 0.606 mg/kg in soup (Erdal & Buchanan, 2005). According to Bhat et al. (2015), 65% of the villages in India are exposed to risk of fluoride from food sources. In addition, Bhat et al. (2015) conducted a research in a village close to a smelter to determine the concentration of fluoride in vegetables grown in that area. Bhat et al. (2015) discovered a mean concentration of 0.71 ± 0.90 ppm in vegetables grown very close to the smelter and a mean fluoride concentration of 0.36 ± 0.69 ppm in vegetables grown 10 km from the smelter.
Abugri and Pelig-Ba (2011) showed that sandy soils are known to have low fluoride concentration especially in climates that are humid meanwhile high fluoride concentrations are found in clay soils. In addition, Abugri and Pelig-Ba (2011) also added that some of the common fluoride compounds found in soils include sodium fluoride (NaF), ammonium fluoride (NH4 F), aluminum fluoride (AlF3 ), calcium fluoride (CaF2) and aluminosilicates such as (Al2(SiF6)2).
In Chiang Mai, Thailand, McGrady et al. (2012) concluded that groundwater with high fluoride content that was used for cooking by the people caused severe pitting of the teeth, hypomineralization and the loss of surface enamel. In addition, 98% of the subjects of the research conducted by McGrady et al. (2012) consume rice as a regular meal.
17
Rice is very common in Thailand and it has the ability to absorb fluoride at the stage of cultivation to the stage of preparation. Buzalef et al. (2001) stated in their research that some cereals are known to contain high concentrations of fluoride. In Brazil, two types of commercially sold cereal products, namely Neston and Mucilon, had considerably high concentration of fluoride (6.2 and 2.44 ppm respectively). Cooking with fuels rich in fluoride, such as coal, can also result into the intake of fluoride from the prepared meals and through inhalation. In addition, the consumption of tea, which is very common in some parts of Asia, can result into the ingestion of fluoride because of the high fluoride content of tea leaves (WHO, 2010). Studies conducted by Singer et al. (1967), showed different species of tea leaves analyzed in order to determine the fluoride content (Table 3). Research in China showed that there is a respondents showed signs of dental fluorosis despite the fact that the drinking water in the region contains low concentrations of fluoride. The consumption of brick tea containing high fluoride concentrations was responsible for the prevalence of dental fluorosis in the region (Cao, Zhao, & Liu, 1997).
Table 3. Fluoride content and percentage of fluoride extracted in tea plants (4-5 min extraction time) (Source: Singer et al., 1967).
18
Fluoridation of Salt
Fluoridation of salt have been employed in several countries since identification of the effects of fluoride consumption in tackling dental caries. Salt fluoridation programs have been implemented in countries, such as Germany, Switzerland, Czech Republic, Colombia, Jamaica, Cuba and other countries (O’Mullane et al., 2016). In water fluoridation, citizens have little or no option asides from buying bottled water but to drink community fluoridated water. The only advantage that salt fluoridation has over community water fluoridation is the fact that fluoridated salt can be sold alongside non-fluoridated salt. Studies conducted in 1965-1985 in Hungary, Colombia, and Switzerland, showed that the effect of salt fluoridation produced similar results in tackling dental caries compared to water fluoridation (Jones et al., 2005). Since the introduction of salt fluoridation in Costa Rica, there have a 73% reduction in the prevalence of dental caries among 12-year-old children over the period of 15 years (Peterson et al., 2008). Salt fluoridation needs to be regulated especially in places where there are other sources of fluoride. A salt fluoridation program introduced in some Mexican states only allows salt fluoridation where fluoride concentration in water is below 0.7 mg/l (Soto-Rojas et al., 2004). Many countries are implementing such programs however, these programs contribute to the amount of fluoride ingested which might ultimately contribute to development of dental fluorosis.
Fluoridation of Milk
The artificial fluoridation of milk has also become one of the ways through which children receive fluoride at an early age so as to prevent the build-up of dental caries. This technique was first seen in Switzerland and later on spread to other countries
19
like Scotland, Hungary, Chile, and China. In Chile, milk-cereal was introduced to ensure that children are taking in enough fluoride to keep them safe from dental caries and in China, fluoridated milk would normally be sent to homes every weekend to ensure adequate fluoride intake (Jones et al., 2005). Research conducted in the United Kingdom by Busell et al. (2016) studied the fluoride content in infant milk and found very low concentration of fluoride in the infant milk widely used. Since the introduction of milk fluoridation in Bangkok, Thailand, in 2000, there has been a 30% decrease in prevalence of dental caries (Peterson et al., 2008). This has encouraged the fluoridation program and could contribute to fluoride intake which could ultimately contribute to development of dental fluorosis.
Other Fluoridated Products
Products such as toothpaste, bottled water, soft drinks, fruit juice, cow’s milk, and some beverages contain certain amounts of fluoride (Erdal & Buchanan, 2005). Many soft drinks and fruit juices are commercially prepared with fluoridated water as a result causing them to have significant concentrations of fluoride in them. Toothpaste is another major source of fluoride in the human body especially in children. Sodium fluoride is one of the most active ingredients in majority of the toothpaste produced in recent times. Fluoridation of toothpaste was first introduced in the 1960s and ever since, it has had a major role to play in the reduction in the prevalence of dental caries worldwide. Cows drink water with high fluoride concentration and feed on either grass or some sort of cow feed with high concentration of fluoride, and they ultimately produce milk that has certain concentrations of fluoride. This cow milk goes through further industrial processing
20
with fluoridated water. Whether fresh or processed, the cow milk will ultimately contain some concentration of fluoride (Erdal & Buchanan, 2005).
Supplements and Infant Formulas
Fluoride supplements and infant formulas have long been prescribed for children in areas that are fluoride deficient. These supplements and formulas, however, may contribute to the risk of dental fluorosis in both fluoridated and non-fluoridated areas. Infant formulas that are soy-based have shown to have considerably high fluoride content and this is because of the natural fluoride content of soy extract (Buzalaf et al., 2001).
Renal Insufficiency
Renal insufficiency in individuals contribute to increased fluoride levels in the body. Individuals who suffer renal insufficiency have increased chances of suffering from any form of fluorosis (dental and skeletal). Kaminsky et al. (2009) highlighted two cases where patients with renal insufficiency suffering from skeletal fluorosis and atherosclerosis had previously been exposed to water containing fluoride concentration between 2-3 mg/L.
Malnutrition
High risk of fluorosis has often been associated with not only presence of fluoride in water but also nutrition of people. Regions where meals have deficiencies in calcium, magnesium, and vitamins were associated with a higher risk of dental fluorosis. According to UNICEF (1999), a regular diet rich in vitamins and calcium can help
21
reduce risk of dental fluorosis. Massler and Schour (1952) added that intake of low levels of fluoride is harmful to malnourished children.
Stages of Dental Fluorosis
Fluorosis is categorized into several levels namely ‘normal’, ‘questionable’, ‘very mild’, ‘mild’, ‘moderate’, and ‘severe’ (Table 4).
Table 4. Level of fluorosis according to Dean’s dental fluorosis index (Source: Committee on Fluoride in Drinking Water, National Research Council, 2006).
22
Fig. 5. Different stages of fluorosis (Source: Brown, 2012).
Dental Fluorosis Correction
Individuals with fluorosed teeth often seek treatment for this defect so as to restore aesthetic value. For fluorosis-affected individuals, several dental procedures can be employed, such as bleaching, micro or macro abrasion, and veneer lamination (Brown, 2012). To restore the normal coloration of the enamel, the tooth has to under a form of bleaching or abrading of the subsurface porosity along with the stains through micro or macro abrasion. Mild cases of dental fluorosis are often treated by bleaching in the dental office or at home (Akpata, 2014). Lee et al. (2005) reported that in the year 2003, the sales of tooth-whitening products that were sold over the counter grew by 57%. The commonly used agents for bleaching are 10% carbamide peroxide and 35% hydrogen peroxide. Micro abrasion techniques often involve the use of hydrochloric acid applied on the area that has been discolored. The hydrochloric acid can be applied alone or sometimes in a pumice mixture (Dazell, Howes, & Hubler, 1995). In cases where there is severe fluorosis and the sub surface
23
porosity is deep, micro or macro abrasion cannot work because it will destroy the morphology of the tooth hence the need for veneering. In addition, cases where there has been a loss of 50% of the enamel, crowning of the fluorosed tooth/teeth is employed (Akpata, 2014).
Methods of De-fluoridation
In areas where fluoride is naturally high in water, different techniques, such as ion-exchange, coagulation-precipitation, nano-filtration, and adsorption, have been employed to reduce the fluoride content to reduce risk of dental fluorosis. Parts of India have employed a technique known as Nalgonda Technique (flocculation of fluoride ions with Alum) in order to reduce fluoride content of water (McGrady et al., 2012).
Parental vigilance is highly recommended for children while brushing their teeth in order to avoid excessive use of toothpaste and in many cases swallowing of toothpaste. Studies conducted in Malaysia showed that 50.7% of 373 children never get supervised by their parents while they brush their teeth (Tay, Zainudin, & Jaafar, 2011). The British Fluoridation Society (2004) advices that parents ensure that their kids apply only pea-sized amount of toothpaste and brush not more than twice a day.
Based on the literature, very few studies about dental fluorosis have been conducted in Nigeria. I am aware of only one study focused on the relationship between dental fluorosis and the concentration of fluoride in water sources. This study was conducted in Jos, Plateau State, north-central Nigeria (El Nadeef & Honkala, 1998). In another study in Borno State, researchers found that fluoride levels were high in
24
water (Waziri et al., 2012). However, the investigators did not also evaluate the prevalence of fluorosis and social impacts of the defect as part of their study. In Zing, Taraba State, local residents have long been aware of teeth discoloration among its inhabitants. However, this have never been specifically studied in the region. Therefore, I assessed fluoride levels in natural and commercial drinking water sources in Zing LGA to determine the prevalence of dental fluorosis in children who were born in Zing. I also assessed basic social impacts in children with the condition. The study will help raise awareness on dental health and drinking water in north-eastern Nigeria. In addition, I will share my findings with the local communities of Zing, government agencies, public health organizations, and dental societies in Nigeria.
25
HYPOTHESES AND AIMS & OBJECTIVES
Null Hypothesis (H0): Concentrations of fluoride in water sources in Zing LGA do not exceed WHO permissible limits.
Research Hypothesis (H1): Concentrations of fluoride in water sources in Zing LGA exceed WHO permissible limits.
Research Question: Is there a relationship between the fluoride concentration of drinking water sources in Zing Local Government Area (LGA), Taraba State, eastern Nigeria, and the prevalence of dental fluorosis among children in the community
Aims:
• To investigate the relationship between dental fluorosis in children and fluoride concentration in drinking water sources in Zing Local Government Area (LGA), a rural community in Taraba State, eastern Nigeria
• To access social impacts of dental fluorosis in children
Objectives:
• To identify drinking water sources used by people
• To determine fluoride concentrations in these water sources
• To compare observed fluoride concentrations with international permissible standards
• To identify social or emotional impacts associated with having dental fluorosis as a child
• To determine dental hygiene practices
• To share findings with governmental and non-governmental authorities situated in the area
26
DISCLAIMER: All project works, files and documents posted on this website, UniProjectTopics.com are the property/copyright of their respective owners. They are for research reference/guidance purposes only and some of the works may be crowd-sourced. Please don’t submit someone’s work as your own to avoid plagiarism and its consequences. Use it as a reference/citation/guidance purpose only and not copy the work word for word (verbatim). The paper should be used as a guide or framework for your own paper. The contents of this paper should be able to help you in generating new ideas and thoughts for your own study. UniProjectTopics.com is a repository of research works where works are uploaded for research guidance. Our aim of providing this work is to help you eradicate the stress of going from one school library to another in search of research materials. This is a legal service because all tertiary institutions permit their students to read previous works, projects, books, articles, journals or papers while developing their own works. This is where the need for literature review comes in. “What a good artist understands is that nothing comes from nowhere. All creative work builds on what came before. Nothing is completely original.” - Austin Kleon. The paid subscription on UniProjectTopics.com is a means by which the website is maintained to support Open Education. If you see your work posted here by any means, and you want it to be removed/credited, please contact us with the web address link to the work. We will reply to and honour every request. Please notice it may take up to 24 – 48 hours to process your request.
