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Year : 2020  |  Volume : 11  |  Issue : 2  |  Page : 66-71

Prevalence of dental fluorosis in 6–14 year old children in Greater Noida city, Uttar Pradesh – An epidemiological study

Department of Pedodontics and Preventive Dentistry, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India , India

Date of Submission25-Oct-2019
Date of Acceptance19-Mar-2020
Date of Web Publication08-Jul-2020

Correspondence Address:
Dr. Dhirja Goel
Department of Pedodontics and Preventive Dentistry, School of Dental Sciences, Sharda University, Greater Noida - 201 310, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/srmjrds.srmjrds_76_19

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Background: Endemic fluorosis is one of the major health problems in India. About 96% of the fluoride found in the body is in bones and teeth. When ingested in adequate quantities, fluoride is beneficial for teeth by reducing the level of dental caries, whereas the ingestion of fluoride in higher concentrations may cause fluorosis. Objectives: The objective of the study was to find the prevalence of dental fluorosis in school-going children of 6–14 years in Greater Noida City, residing there since birth. The severity of fluorosis was determined after estimating the fluoride concentration in drinkable groundwater. The distribution of dental fluorosis was then compared according to various variables. Materials and Methods: A sample of 1516 school-going children, residing in the Greater Noida since childhood and consuming the groundwater, were taken across various schools from all five directions. These children were examined for dental fluorosis according to the Dean's criteria for assessment. Results: The prevalence of dental fluorosis in 6–14-year-old school-going children was 69.9%. A stepwise increase in prevalence was noted with a corresponding rise in the water fluoride content in different zones of the city. Conclusion: The prevalence of dental fluorosis was found to be 69.9% with the groundwater concentration gradient ranging from 1.6 to 2.4 ppm.

Keywords: Dental fluorosis, prevalance, survey

How to cite this article:
Singh S, Goel D, Awasthi N, Khandelwal D, Sharma A, Singh N. Prevalence of dental fluorosis in 6–14 year old children in Greater Noida city, Uttar Pradesh – An epidemiological study. SRM J Res Dent Sci 2020;11:66-71

How to cite this URL:
Singh S, Goel D, Awasthi N, Khandelwal D, Sharma A, Singh N. Prevalence of dental fluorosis in 6–14 year old children in Greater Noida city, Uttar Pradesh – An epidemiological study. SRM J Res Dent Sci [serial online] 2020 [cited 2022 Dec 8];11:66-71. Available from:

  Introduction Top

Fluoride, a naturally occurring essential microelement, is required for proper growth and function of the body. It is most frequently found in underground water due to weathering and leaching of fluoride-containing minerals from sediments and rocks. India lies in the geographical fluoride belt,[1] and endemic fluorosis remains one of the major health problems in India. The endemic fluoride belts serve as natural laboratories to study the effect of fluoride concentration on dental fluorosis.[2]

The current scenario in India estimates that 62 million people including 6 million children have serious health problems due to the consumption of fluoride-contaminated water. About 96% of the fluoride found in the body is in bones and teeth.[3] When ingested in small quantities (<0.5 mg/L or 0.7 ppm), fluoride is beneficial for teeth as it helps in reducing dental caries, while its ingestion in higher concentrations (>1.5 mg/L) may lead to fluorosis, both dental as well as skeletal.

Therefore, it is necessary to explore the geographical distribution and present contamination of fluoride level in water and accordingly develop a strategy for safe drinking water source.[4] The present study aims to determine the prevalence of fluorosis in Greater Noida City, Uttar Pradesh, and to determine its relationship with fluoride levels in drinking water.

  Materials and Methods Top

The study aimed to estimate the prevalence and severity of dental fluorosis among 6–14-year-old school-going children of Greater Noida City, Uttar Pradesh, India. For the study purpose, the entire geographical area of the city was divided into five zones: North zone, West zone, South zone, East zone, and Central zone. Schools with an adequate number of pupils from these five zones were randomly selected as participants for the study. Care was taken to include almost equal number of subjects from each zone.

The sample size consisted of 1516 school-going children of both genders aged 6–14 years studying in Greater Noida City (Uttar Pradesh). The schools included were both private as well as government. An official permission was obtained from the administrative authority of each school for carrying out the study. The samples were selected using stratified random sampling. Children between the ages of 6–14 years who were born and brought up in the study area were included and who were temporary/new residents in the study area were excluded from the study. Children with a history of systemic disease were also excluded from the study. One school was taken from each of the five zones for water sample collection and then dental fluorosis was measured in children from that school. Water collected was then tested for fluoride level using a calibrated spectrometer.

The examination was done by a single examiner and assisted by a person for recording data throughout the study. The children were examined in an upright chair position in natural light, using a plain mouth mirror. Dental fluorosis was recorded on the basis of Dean's Index (1942), WHO criteria 2013.[5]

The codes and criteria were as follows:

  • 0 = Normal: The enamel surface is smooth, glossy, and usually a pale creamy white color
  • 1 = Questionable: The enamel shows slight aberrations from the translucency of normal enamel, which may range from a few white flecks to occasional spots
  • 2 = Very mild: Small, opaque, paper white areas scattered irregularly over the tooth but involving < 25% of the labial tooth surface
  • 3 = Mild: The white opacity of the enamel of the teeth more extensive than for code 2 but < 50% of the tooth surface
  • 4 = Moderate: The enamel surfaces of the teeth show marked wear and a brown stain is frequently a disfiguring feature
  • 5 = Severe: The enamel surfaces are badly affected and hypoplasia is so marked that the general form of the tooth may be affected. There are pitted or worn areas and brown stains are widespread; the teeth often have a corroded appearance.

No radiographs were taken for the clinical examination. The recording was made on the basis of the two teeth which were most affected. If the two teeth were not equally affected, then the score for the less affected was recorded. When teeth were scored, the examiner started at the higher end of the index (i.e. “severe”) and eliminated each score until arrived at the condition that was seen. If there was any doubt then lower score was given.

Data were entered into Microsoft Excel spreadsheet. They were analyzed using SPSS Version 21.0. Armonk, NY: IBM Corp. Continuous variables such as age were summarized as mean and standard deviation. Categorical variables were summarized as frequencies. Keeping in view the categorical nature of the variables, inferential statistics were performed using nonparametric tests of significance. The intergroup comparison of frequencies of various categorical variables was done using Chi-square test. The intergroup comparison of means of parameters was done using an independent test. The level of statistical significance was set at 0.05.

This study was reviewed by the Institutional Ethical Committee of School of Dental Sciences, Sharda University, and clearance was obtained (Ref no. IEC/2016/76-A/48). To ensure uniform interpretation, understanding and application by the examiner, of the grade and criteria for dental fluorosis, the examiner was calibrated and trained in the department.

  Results Top

In this study, a total of 1516 school-going children were examined. Dental fluorosis was seen in 69.9% and was absent in 30.1% of the study population. From the total population, 876 (57.8%) were male and 640 (42.2%) were female. When the gender-wise comparison of prevalence of dental fluorosis was seen, it turned out to be statistically nonsignificant [Table 1].
Table 1: Gender-wise comparison of prevalence of dental fluorosis

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The study was conducted by dividing the city into five zones, and the study population in each zone was recorded as follows: in North zone, 201 (13.3%), South zone: 266 (17.5%), East zone: 295 (19.5%), West zone: 343 (22.6%), and Central zone: 411 (27.1%) [Table 2]. Among the five zones, East zone showed the highest prevalence of dental fluorosis (85.1%), followed by South zone (82%), West zone (72.6%), Central zone (59.4%), and North zone (48.8%). When the area-wise comparison of prevalence of dental fluorosis severity was done using Chi-square test, then a statistically significant difference was found. The very mild form of dental fluorosis was seen in a maximum number of cases in all the five zones: East (36.3%), South (22.2%) West (38.5%), Central (22.1%), and North (22.9%). Questionable form of dental fluorosis was significantly highest in the East zone (20.0%). Very mild form was significantly highest in the West zone (38.5%). Mild, moderate, and severe form was significantly highest in the South zone (20.7%, 18.4%, and 4.9%, respectively) [Table 3] and [Graph 1].
Table 2: Distribution of the study population according to the different areas

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Table 3: Area-wise comparison of prevalence of different severity levels of dental fluorosis

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A stepwise increase in the prevalence was noted with a corresponding increase in the water fluoride content in different zones. The sample revealed an increase in the severity of dental fluorosis with an increase in groundwater fluoride concentration. The ground water fluoride concentration was found to be 1.6 ppm in North and Central zones (fluorosis present was 48.8% and 59.4%, respectively), 1.8 ppm in West zone (fluorosis present 72.6%), 1.9 ppm in East zone (fluorosis present 85.1%), and 2.4 ppm in South zone (fluorosis present 82%) [Table 4] and [Graph 2].
Table 4: Area-wise prevalence of dental fluorosis

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In the total study population, the proportion of 6 year old was 91 (6%), 7 year old was 88 (5.8%), 8 year old was 159 (10.5%), 9 year old was 164 (10.8%), 10 year old was 252 (16.6%), 11 year olds was 192 (12.7%), 12 year old was 227 (15%), 13 year old was 170 (11.2%), and 14 year old was 173 (11.4%). When the comparison of prevalence of severity of dental fluorosis was done according to different ages, using Chi-square test, a statistically significant difference was found (P < 0.0001). The maximum prevalence of fluorosis was seen in 14-year-old (78%) children and the least was seen in 6-year-old (40.7%) children.

The prevalence of “Normal” enamel was significantly more common among 6-year-old (59.3%) children, “Questionable dental fluorosis” among 14-year-olds (24.3%), “very mild” dental fluorosis among 7-year-olds (34.1%), “mild” dental fluorosis among 11-year-olds (17.2%), “moderate” dental fluorosis among 12-year-olds (13.7%), and “severe” dental fluorosis among 9-year-old (4.9%) children [Table 5].
Table 5: Age group-wise comparison of prevalence of different severity types of fluorosis

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  Discussion Top

Moderate-to-high fluoride level in groundwater is reported as one of the major environmental issues of various countries that include India as well, which affects an estimated population of 200 million people.[6]

Since India has numerous fluoride-rich belts, it represents itself as a good source for collecting data regarding the prevalence and severity of fluorosis in various regions affected. These data collected from various parts can help people globally to cater to the needs of patients suffering from fluorosis. Endemic fluorosis has been reported in 20 Indian states, spreading over 65% of the total rural habitations of the country. More than 65 million Indians including 6 million children are at risk due to the presence of fluoride beyond the desirable 1.5 mg/l in drinking water. High concentration of fluoride in underground water has been mainly reported from different regions of Uttar Pradesh, Assam, Andhra Pradesh, Bihar, Chhattisgarh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Odisha, Rajasthan, Telangana, and West Bengal.[6]

Almost 70%–80% of districts in Uttar Pradesh are affected by fluorosis,[7] but only from a very few areas in the state, the data have been reported. One such city which still remains unexplored in relation to the prevalence and severity of fluorosis in the population is Greater Noida City. Therefore, the present study was designed to study about the prevalence of fluorosis in 6–14-year-old school-going children of Greater Noida City (Uttar Pradesh) residing there since birth.

The various surveys conducted, in and around Greater Noida, suggest variable number of data regarding the prevalence of fluorosis. In a study done by Handa et al.,[8] in Gurgaon, it was seen that 46% of the population had dental fluorosis, in which 11.23% had moderate and 9.6% had severe fluorosis. Another study conducted by Tuli et al. in Meerut district reported a high prevalence (%) of Grade 2 fluorosis in schoolchildren.[7] Similarly, the studies conducted in the areas of Agra,[9] Kanpur,[1] Sonbhadra[10] (2009), and other parts of rural areas in Uttar Pradesh have significantly shown that these areas have high fluoride content in the water. Districts affected with high fluoride concentration also include Aligarh, Mathura, Ghaziabad, Rae Bareli, Rampur, and Unnao.[11] (2007).

Children which were going to school were included for the study because they can be easily examined and also review can be carried out if necessary.[12] The distribution of dental fluorosis was compared according to the gender and age. The severity of fluorosis prevailing in the child's teeth was assessed after estimating fluoride concentration in drinking groundwater. The age group from 6 to 14 years was selected as the permanent dentition starts to erupt and gets completed between this age span.

When the gender-wise comparison was done for the prevalence of fluorosis, it was found nonsignificant. These findings are in accordance with the findings reported by Kotha et al.,[13] Avocefohoun et al.,[14] Tuli et al.,[7] Franzolin Sde et al.,[15] and Venugopal.[16]

From the total population, 69.9% of the children were found to have dental fluorosis across all five zones of the study area. This was attributed to high levels of fluoride present in drinking groundwater that ranged from 1.6 ppm to 2.4 ppm. According to the WHO, the maximum permissible limits for drinking groundwater range from 0.7 to 1.2 ppm. It can be studied from the data that as the fluoride content of the drinking water increases, the prevalence of dental fluorosis also increases. Although the level of fluoride in drinking groundwater in the East zone (1.9 ppm) was lesser than South zone (2.4 ppm), still prevalence of fluorosis was found to be slightly more in East zone(85.1%) in comparison to south zone (82%). The possible contributing factor could be that for the study population in South zone, the school happened to be a private school and children carry their own water from home; thus, their intake of school water is very less as compared to the East zone which is a government school. Moreover, the schoolchildren in East zone reside in the same locality as the school consuming the same groundwater both at school and at home, unlike the schoolchildren of South zone who come from different localities. However, when the severity levels were compared, South zone had maximum cases of mild, moderate, and severe level of dental fluorosis.

When the age-wise comparison was done, the prevalence of fluorosis was seen highest in 14-year-old children (78%). The possible explanation for this can be that fluorosis becomes more severe with age, an observation which could be explained by subsurface porosities, which are created during the development of the enamel when the high concentration of fluoride is in the environment and disturbs the ameloblast in creating regular enamel walls. These subsurface porosities might change into pitting and elevate the definition of the fluorosis severity.[17] In a study carried out by Rwenyonyi et al.,[18] among children of age group 10–14 years, there was a significant increase in the severity of fluorosis with increasing age in a fluoride community having 2.5 ppm of fluoride level in drinking water.

Since, no study has been conducted in the Greater Noida area for the estimation of dental fluorosis in children, there is a shortage of data in this regard. Hence, further studies are required to substantiate these findings, as the results of this study show that a significant number of children are affected with dental fluorosis.

Fluoride concentration in the groundwater of the study area varied from 1.6 to 2.4 ppm. Awareness programs for the impact of fluoride on general and dental health should be emphasized through education of the public and community participation. The study recommends extensive screening of groundwater sources for fluoride levels. Controlling the fluoride intake is the best preventive measure for dental fluorosis. Newer government policies should be employed to make a central water defluoridation unit in area with high fluoride level. Moreover, creating more public awareness on the various home defluoridation techniques is also equally required. This requires the synergistic action of health planners, health administrators, water supplying agencies, and government.

  Conclusion Top

  • The prevalence of dental fluorosis was found to be 69.9% in 6–14-year-old school-going children in Greater Noida City, Uttar Pradesh. There was a significantly strong positive correlation between the Dean's index and fluoride concentration in drinking water
  • The fluoride concentration in the groundwater of Greater Noida City ranged from 1.6 to 2.4 ppm
  • The prevalence of dental fluorosis was not statistically significant according to the gender distribution.

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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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