dental fluorosis chemistry and biology pdf books

Dental Fluorosis Chemistry And Biology Pdf Books

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This study was conducted to investigate the high incidence of mottled teeth among residents of an area with hot springs in the Choma District of the Southern Province of Zambia.

Water fluoridation is the controlled adjustment of fluoride to a public water supply solely to reduce tooth decay. Fluoridated water contains fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride. Although fluoridation can cause dental fluorosis , which can alter the appearance of developing teeth or enamel fluorosis , [3] the differences are mild and usually not an aesthetic or public health concern. Drinking water is typically the largest source; [14] other methods of fluoride therapy include fluoridation of toothpaste, salt, and milk. The Australian government states that water fluoridation is the most effective way to achieve fluoride exposure that is community-wide.

Water fluoridation

This study was conducted to investigate the high incidence of mottled teeth among residents of an area with hot springs in the Choma District of the Southern Province of Zambia. It was analysed for fluorides and other drinking water quality parameters. Fluoride concentrations ranged from 5. Fluoride levels in water from hot spring water samples exceeded the 1. We conclude that the high prevalence of mottled teeth among residents of the study area is a case of endemic dental fluorosis associated with drinking water from hot springs containing high concentrations of fluoride.

Dental fluorosis, or mottled enamel, is a common disorder of teeth associated with drinking water containing high concentrations of fluoride. Dental fluorosis has been reported in communities living in areas where drinking water contains fluorides at concentrations as low as 1. In Zambia, dental fluorosis is not very common and is generally not well documented. However, an area with hot springs in the Choma District of the Southern Province of Zambia has a high incidence of people with discoloured and mottled teeth.

Residents of the area have long suspected this problem to be associated with the drinking of water from hot springs. Prior to this study, no scientific investigation had been conducted to determine whether there was any link between the occurrence of discoloured and mottled teeth among residents of the area in Choma with hot springs and consumption of water from the springs. This study was conducted to establish whether there was an association between the incidence of discoloured teeth among residents of this area and the sources of drinking water in the area, and whether the incidence of discoloured teeth was associated with levels of fluoride in drinking water.

Much of the Choma District is underlain by granite rocks that are part of the large granitoid mass known as the Choma—Kalomo batholith, which extends for several tens of kilometres between the Choma and Kalomo Districts Newton, The Choma District is in the dryer part of Zambia, locally referred to as the medium rainfall region, which in the past two decades has experienced frequent dry spells and droughts.

Availability of water for domestic and agricultural use is often a problem in this region, particularly in the hot dry months of August—October, when most seasonal streams dry up. During such periods, people depend on water from deep wells or have to travel long distances to get it.

In locations with hot springs, residents have used water from the springs for their domestic requirements, livestock and irrigating crops in the dry season. The majority of the residents in our study area are workers on commercial tobacco farms and ranches, while others are small-scale farmers, engaged in growing maize or rearing cattle.

Our target group in the study was the children of this low income group, who are the main victims of the problem of mottled and discoloured teeth. A survey involving pupils at a Basic School in the study area was conducted, using a structured questionnaire.

Results of the dental examination, indicating whether or not pupils had clinical manifestation of dental fluorosis and the degree of severity of the symptoms were captured on the same sheet that had other data on the background. After the survey water samples were collected from main drinking water sources at locations where the majority of the pupils interviewed had lived between birth and age 7. The water samples were collected in triplicate at each location in 1-l polyethylene bottles and transported to the lab.

The water temperature, pH and electrical conductivity were measured on site using a portable pH, EC Temperature, multiparameter analyser, model Eijkelkamp The following day, the water samples were analysed for fluoride concentrations using an Ion selective electrode and for other drinking water quality parameters following standard methods outlined in Clesceri, Greenberg, and Eaton Furthermore, samples were collected from rock outcrops, at hot spring sites, at locations where outcrops were present at or near the hot springs.

Thin sections of rock samples were made and studied using a Reichert Neovar-Pol petrographic microscope, in order to determine the mineralogy of the rocks. To test whether there was an association between the incidence of discoloured teeth among pupils and main sources of drinking water between birth and the age of 7 a Chi-squared test was used to analyse the data obtained from the survey.

To establish whether there was a significant difference between the levels of fluorides in water from hot springs and that from other drinking water sources, a t test was used. The statistical analyses were carried out using the software packages SPSS version The overall incidence of moderate to severe dental fluorosis at the school was More specifically, the statistics indicated that the occurrence of clinical symptoms of dental fluorosis was associated with drinking of water from hot springs, while the absence of symptoms of dental fluorosis was associated with drinking water from other non-hot springs sources.

The temperature of water from hot springs measured in the field ranged from In general, water with higher temperatures contained higher fluoride concentrations than that with lower temperatures. There was, however, no statistically significant relationship between water temperature and the concentration of fluoride in the water. The range of fluoride concentrations of water samples from hot springs and from other water sources is shown in Fig.

In contrast, fluoride concentrations in water from other sources are generally far below the WHO guideline, except for samples collected from a shallow well at Miller Farm, which is less than a kilometre away from a hot spring. Fluoride concentrations in water from hot springs and other drinking water sources in the study area Choma District. The hot springs of the study area emanate from within granitic rocks that make up the large granitoid mass called the Choma—Kalomo batholith.

The granites are poorly exposed at the sites where most of the hot springs are located, except at Chibimbi, where there are more extensive outcrops. Two varieties of granite were observed in the field. The most common variety is a pink medium to coarse grained porphyritic granite that varies in composition from leucocratic K-feldspar granite to mesocratic biotite granite.

The second variety is a grey, porphyritic, coarse to medium-grained biotite-hornblende granite. Both rock types are weakly to strongly foliated and in the more strongly deformed parts, the preferred orientation of the minerals, particularly biotite, give the rock a gneissic appearance. The surfaces of rock outcrops close to the hot springs appear whitish due to weathering of the feldspars.

The granite is a coarse grained rock that consists of potassium and sodium feldspars, biotite, hornblende and quartz with accessory apatite and iron ore. All the hot springs are located along fault structures in the granite. Faulting is indicated by sheared granite where the rocks are exposed at the surface.

The microcline is subhedral to anhedral and shows moderate to strong alteration to sericite. Plagioclase occurs as a ground mass mineral with anhedral to subhedral grain shapes showing deformation twinning and moderate to strong kaolinisation and epidotisation.

The biotite is green and occurs as unevenly distributed clots and flakes scattered in the rock. Hornblende occurs as isolated euhedral to subhedral green pleochroic crystals associated with biotite. The granite from Chibimbi hot springs is pink in colour and in the main fault zone has been transformed into mylonite, resembling quartzite.

In the thin section, the rock consists of microcline, sodic plagioclase and quartz, all of which show a high degree of recrystallisation and granulation. Accessory minerals include iron oxide, epidote and apatite. The grey granite also displays varying degrees of alteration of the feldspars to sericite and kaolinite. The quartz in both rocks occurs as anhedral grains and shows undulose extinction indicative of the deformation suffered by the rocks.

All the hot springs in the study area are located at edges of gently sloping topographic highs that separate shallow, broad valleys that characterize the drainage pattern in the area.

In all the areas investigated, the hot springs were observed to be located along faults that have been identified using both satellite imagery and field observations.

In the field, the presence of faults is indicated by the presence of fault breccia, silicification and shearing of the granite. Figure 3 shows the location of hot springs at Miller and Ross Farms, and at Semahwa River, in relation to the geology and occurrence of faults in the area.

It is important to mention that the study area is in a rural district with no industrial activity that could possibly serve as an anthropogenic source of fluoride. Additionally, the study area and its surrounding environment are very sparsely populated. With the exception of the few locations with human dwellings, most of the area is under the natural Miombo woodland that characterises much of the plateau region of Zambia.

Consequently, the mostly likely major sources of fluoride for the residents of this area are the water they drink and the food they eat. Considering that the majority of children included in the study are the offspring of farm workers and peasant farmers, much of the food they eat is locally produced. Furthermore, because the majority of the children in this study came from poor families who often cannot afford toothpaste and therefore do not usually use it, fluoridated dental products are not likely to be significant sources of fluoride in this population.

There is no fluoridation of water in Zambia, so the consumption of municipally fluoridated water cannot be considered a possible source of fluoride either. Results of this study have shown that the high incidence of discoloured teeth among the residents of the area of the Choma District with its hot springs is strongly associated with the drinking of water from hot springs that contain high levels of fluoride.

Mamuse reports a similar observation in the Chimanimani District in Eastern Zimbabwe in an area with hot springs where the incidence of dental fluorosis among school children is Our estimate of daily fluoride intakes for children in the study area drinking hot spring water with an average concentration of 6.

These fluoride intake values are much higher than the 0. On the other hand, children drinking water from other sources with an average F concentration of 0. In view of the above discussions and of the fact that fluoride concentrations in water samples from hot springs are much higher than the suggested maximum limit for drinking water of 1. Biotite, hornblende and apatite are all present in granite samples obtained from sites where the hot springs are located.

The high fluoride levels in water from hot springs are most probably due to the chemical weathering of fluoride-bearing minerals, which happens upon contact with the hot water.

Dissanayake has also attributed the high levels of fluoride in fluorosis-affected regions of Sri Lanka to the presence of high-grade metamorphic rocks containing fluorine-bearing minerals such as micas, hornblende and fluorite. Our studies have revealed evidence of chemical weathering of granitic rock at sites with hot springs. Results of petrographic analyses of thin sections of rocks show that hydrothermal alteration has occurred in rocks at hot springs, as evidenced by the transformation of K- feldspars to sericite and the alteration of plagioclase to epidote and kaolinite.

In addition, the fluorine-bearing minerals biotite and hornblende have also been altered to various degrees and have completely disappeared in the fault rocks. We think that the chemical alteration of the rocks has been facilitated by fault structures that serve as easy channels for water movement over a larger surface area of exposed minerals. Alarcon-Herrera, T. Well water fluoride, dental fluorosis and bone fractures in Guadiana Valley of Mexico.

Fluoride, 34 2 , — Google Scholar. Aoba, T. Dental fluorosis: chemistry and biology. Critical Reviews in Oral Biology and Medicine, 13 2 , — Appelo, C. Geochemistry, Groundwater and Pollution. Rotterdam: Balkema, p. Billings, R. Pediatrics , 4 , — Clesceri, L. Dalal-Clayton, D. A Geomorphic Legend for Zambia. Technical Guide No. Soil Survey Unit. Research Branch.

Water fluoridation

These metrics are regularly updated to reflect usage leading up to the last few days. Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts. The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric. Find more information on the Altmetric Attention Score and how the score is calculated. Advances in biosensor engineering have enabled the design of programmable molecular systems to detect a range of pathogens, nucleic acids, and chemicals.

Akuno, G. Nocella, E. Milia, L. Gutierrez; Factors influencing the relationship between fluoride in drinking water and dental fluorosis: a ten-year systematic review and meta-analysis. J Water Health 1 December ; 17 6 : — The relationship between naturally fluoridated groundwater and dental fluorosis has received large attention from researchers around the world. Despite recognition that several factors influence this relationship, there is a lack of systematic studies analyzing the heterogeneity of these results.

Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Aardema, M. Sodium fluoride-induced chromosome aberrations in different cell cycle stages. Abboud, T.

Fluoride in Volcanic Areas: A Case Study in Medical Geology

DOI: Abstract PDF. Dental fluorosis is a chronic fluoride —induced condition in which an excess of fluoride is incorporated in the developing tooth enamel and disrupt the enamel formation of the tooth. Prevalence of dental fluorosis due to high levels of fluoride in drinking water is an endemic global problem.

Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. The aim of our research was to review the literature about fluoride toxicity and to inform physicians, dentists and public health specialists whether fluoride use is expedient and safe. Data we used in our review were systematically searched and collected from web pages and documents published from different international institutions.

Volcanic regions have always attracted many people worldwide because of the high fertility of their soils. However, human proximity to volcanoes can lead to several health problems as consequence of the chronic exposure to the materials released from the volcanic activity.

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INTRODUCTION

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FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH

Стратмор кивнул: - Совершенно .

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