Keywords: Dental fluorosis; Haryana; Thylstrup-Fejerskov index; endemic areas.

Introduction

Dental fluorosis is a major endemic oral disease characterized by hypomineralization of enamel caused due to consumption of water containing high concentration of fluoride during developmental stages of teeth.[1]

Fluoride is considered an essential element required for prevention of dental caries. World Health Organization (WHO) has set the upper limit of fluoride concentration in drinking water at 1.5 mg/l[2] and the Bureau of Indian Standards, has therefore, laid down Indian standards as 1.0 mg/l as maximum permissible limit of fluoride with further remarks as “lesser the better.” Intake of fluoride higher than the optimum level is associated with dental and skeletal fluorosis.[3],[4]

Caries preventive effect of fluoride at concentration of 1 ppm has been well documented[5],[6] but at the same time ill effects of chronic fluoride toxicity in the form of dental fluorosis and skeletal fluorosis is also a matter of concern.

Dental fluorosis is prevalent in many areas of Asia and Africa where the ground water contains higher concentration of fluoride. More than 23 countries in the world are endemic fluoride areas in which approximately 100 million people are suffering from dental fluorosis.[7]

In India, 15 out of 32 states have been affected by the burden of dental fluorosis. It is more prevalent in the state of Bihar, Tamil Nadu, Andhra Pradesh, Gujarat, Rajasthan, Punjab and Haryana which is due to consumption of drinking water containing high concentration of fluorides.[8]

Majority of the rural population in India are dependent on the ground water for drinking purposes hence they are at risk of developing dental fluorosis.

In Haryana state, almost all districts except 6 (Panchkula, Yamunanagar, Ambala, Kurukshetra, Kaithal and Panipat) have ground water with medium to high fluoride concentration.[9] Prevalence of dental fluorosis among children in ranged from 30% to 94.85% in the high-fluoride villages and from 8.80% to 28.20% in the low/normal-fluoride villages.[10]

There is limited amount of information about the prevalence and severity of dental fluorosis in school children of endemic fluoride areas of Haryana. Hence the study was undertaken with the aim to assess the prevalence of dental fluorosis among 11-14 years school children in endemic fluoride areas of Haryana and to find their treatment needs.

 Materials and Methods

A cross-sectional study was conducted among 11-14 years old School children in endemic fluoride areas of Haryana (India) for a period of six months from October 2015 to March 2016. The study protocol was reviewed by Institutional Ethics Review Board and ethical clearance was granted (PGIDS/IEC/2015/56). An official permission was obtained from the District Education Officer and also from all the concerned school authorities.

After explaining the purpose and details of the study, written informed consent was obtained from the parents of all children aged 11-14 years. The 11-14 years children who were permanent residents of their village since birth were included in this study. Children who were uncooperative, with systemic diseases and developmental anomalies and whose parents did not give consent were excluded.

Depending upon the prevalence of severe dental fluorosis 25% which was obtained in pilot study the sample size was calculated using the standard formula z2pq/l2 seeking results at 95% confidence interval for which the value of z = 1.96, margin of error was taken as 10%. As the sampling technique employed was cluster random sampling, thus a design effect of 1.8 was used to adjust sample size. The minimum sample size was determined to be 2075. And the participants of pilot study were not included in the main study.

The sampling frame consisted of schools in endemic fluoride areas based on the data provided by central ground water board, Haryana. There are 14 districts that are declared as endemic areas for fluoride. Cluster random sampling was employed in which 3 districts were selected out of 14 districts. In each district 2 tehsils were selected based on simple random sampling procedure. In each tehsil six schools were selected out of which 4 schools from the rural areas and 2 schools from urban areas were selected and from each school approximately 40-60 children were selected with 50 as average cluster size.

Prior to conducting the study, the investigator was trained in the Department of Public Health Dentistry, Post Graduate Institute of Dental Sciences Rohtak. Intra-examiner reliability was found to be 0.82.

A single examiner conducted the examination where children were examined in school rooms with the help of mouth mirror and natural light as a source of illumination. Prior to examination buccal and facial surface of all the teeth was cleaned and dried with gauze in order to remove debris and biofilm. Type III examination was done in which dental fluorosis was recorded by the Thylstrup-Fejerskov index (TF index) given by Thylstrup A, Fejerskov O, 1978.[11] The children were educated about the importance of oral health and various oral hygiene habits. Children requiring immediate care were referred to the Department of Public Health Dentistry PGIDS Rohtak for further treatment.

Statistical analysis

Data entry and analysis were performed using Statistical Package of Social Sciences (SPSS) software version 18.0. Descriptive statistics were used to describe the prevalence and severity of dental fluorosis. Chi square test was used to find association between TFI scores and gender, age categories. p value of <0.05 was taken to indicate the statistical significance.

 Results

The present study was a cross-sectional study conducted in endemic fluoride areas of Haryana, India in which 2200 subjects between ages 11-14 years were recruited for the present study out of which 997 (45.3.%) were males and 1203 (54.7%) were females. The mean age of study population was 12.38 ± 1.074 [Table 1].{Table 1}

Prevalence of dental fluorosis (TFI) reached 96.6% with most children falling in TFI score 2, 3, 4 and 5 categories There was significant difference between different age groups and prevalence of dental fluorosis (P = 0.05). Children of 13-14 years age group were found to have the highest prevalence of dental fluorosis i.e (TFI score 5-9) [Table 2].{Table 2}

Mean TFI score of study population was found to be 3.19 ± 1.551. There was significant difference found between gender and prevalence of dental fluorosis (P = 0.00). Among males and females majority of TFI scores found were 2, 3, 4 which is 67.5% and 65.4% respectively [Table 3].{Table 3}

According to Mabelya L, et al.[12] TFI scores can be compared with Dean’s fluorosis index modified criteria. After categorization of TFI scores on ordinal scale according to Dean’s fluorosis modified index it was found that around 40% of children had very mild to moderate dental fluorosis and 18.6% of children have severe dental fluorosis [Table 4].{Table 4}

About 30.8% of children with TFI scores (1, 2) needed bleaching of their teeth. Around 47% of children having mild to moderate fluorosis (TFI scores 3, 4) require microabrasion on their teeth. 18.3% of children with dental fluorosis (TFI scores 5-7) required laminates and veneers on their teeth. And those children (0.4%) with severe dental fluorosis (TFI scores 8-9) required crown on their teeth [Table 5].{Table 5}

Discussion

Dental fluorosis is one among the major public health problems in many parts of the world including India. Since its first reporting as “mottled enamel” by Fredrick McKay, dental fluorosis is extensively described by investigators as the visible sign of chronic fluoride toxicity.[13] Endemic dental fluorosis is caused by the excessive ingestion of fluorides (>1 ppm) due to the contamination of soil, air and water.[14],[15]

Dental fluorosis is a developmental condition having a dose-response relationship. The severity of dental fluorosis is dependent on the quantity and timing of fluoride ingestion during developmental period.[16]

The clinical appearance of the teeth vary from barely noticeable changes to an ugly brown stain with more pronounced pitting and loss of architecture.[17]

Ground water has been a significant source for domestic consumption, irrigation and industrial use in India. More than 85% of rural and 50% of urban domestic water requirements is met from ground water resources.[18] As Haryana is a major endemic fluoride area where ground water fluoride concentration is high, there is scarcity of data regarding prevalence of dental fluorosis and treatment needs. Hence, the present study was conducted.

Our study revealed that most of the children were diagnosed with TFI score 2, 3, 4 and 5 categories (Equivalent to mild to severe degree of dental fluorosis according to modified Dean’s Fluorosis Index (1942).[19] 44.8% of children had a score of TFI >4 which was characterized by brown staining and opacities covering more than 50% of tooth structure. In our study, 11.6% had questionable or very mild fluorosis (19.2%); and 21.0% had mild (26.1%), moderate (12.1%), and severe (6.6%) fluorosis.

Milder form of dental fluorosis was more common than its severe form and similar results were found by Aguilar-Diaz et al.[20] Onoriobe U, et al.[21] Tellez M, et al.[22] and in contrast to study conducted by Do LG, et al.[23]

The fluoride concentration in the present study ranged from 0.23 ppm to 25.7 ppm which was directly proportional to the TFI scores. Majority of the school children at present used purified tap water for drinking purpose but consumed ground water with increased concentration of fluoride during their developmental stages and this may be the reason for occurrence of dental fluorosis. The Government of Haryana has made provision of supply of tap water to most of the villages which have reduced the risk of dental fluorosis.

Our study revealed that the prevalence of dental fluorosis was 96.6%. Similar results were found by Vuhahula et al.[24] in Tanzania. In a similar study conducted by Mann et al.[25] prevalence of dental fluorosis was found to be 100%. In another study conducted by Onoribe U, et al.[21] it was found that 28.2% of the children were affected by fluorosis; which was similar to the study conducted in Kanpur, Uttar Pradesh (18%.)[26] As Haryana is one among the endemic fluoride areas in India, the prevalence of dental fluorosis ranged from 30% to 94.85% in the high-fluoride villages and from 8.80% to 28.20% in the low/normal-fluoride villages.[10],[27],[28]

The data from present study revealed that prevalence of moderate to severe dental fluorosis (TFI 4 to 8) among the female subjects was found to be higher than their male counterparts. This finding is in contrast with the studies conducted by Khan SQ, et al.[29] Kotecha PV, et al.[30]

In the present study around 30.8% of children fell in the categories of TFI scores (1, 2) who required bleaching of their teeth. Around 47% of children having mild to moderate fluorosis (TFI scores 3, 4) required microabrasion on their teeth and this may be followed by bleaching by sodium hypochlorite or carbamide peroxide. Satisfactory results were obtained in study conducted by Gupta et al.[31] Penumatsa NV, et al.[32] Those children effected by severe dental fluorosis can be managed by giving laminates/veneers or crown. The present study used TFI index for measuring the level of dental fluorosis which can be used to measure wide spectrum of dental fluorosis in epidemiological surveys.

Limitations

The present study has some limitation of cross-sectional nature of this research. Further data regarding diet history was not taken which might affect the prevalence of dental fluorosis because vegetables grown in endemic fluoride area also affects the dental fluorosis. Considering the mentioned limitations, further research is required in this field.

Conclusion

In conclusion, our findings showed the increased prevalence of dental fluorosis in endemic fluoride areas with mild to moderate level of dental fluorosis. There was an urgent need to reduce the fluoride concentration of drinking water using appropriate defluoridation techniques and esthetic management of dental fluorosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1	Chaudhry M, Prabhakar I, Gupta B, Anand R, Sehrawat P, Thakar SS. Prevalence of dental fluorosis among adolescents in schools of Greater Noida, Uttar Pradesh. J Indian Assoc Public Health Dent 2017;15:36-41.
2	Guideline for drinking water quality. World Health Organization (WHO) 2011.
3	Arlappa N, Aatif Qureshi I, Srinivas R. Fluorosis in India: An overview. Int J Res Dev Health 2013;1:97-102.
4	Zhang BO, Hong M, Zhao Y, Lin X, Zhang X, Dong J. Distribution and risk assessment of fluoride in drinking water in the west plain region of Jilin Province, China. Environ Geochem Health 2003;25:421-31.
5	Dean HT. Endemic fluorosis and its relation to dental caries. Public Health Rep 1938;53:1443-52.
6	Budipramana ES, Hapsoro A, Irmawati ES, Kuntari S. Dental fluorosis and caries prevalence in the fluorosis endemic area of Asembagus, Indonesia. Int J Paediatr Dent 2002;12:415-22.
7	Mollert IJ. Endemic dental fluorosis. In: Prabhu SR, Wilson DF, Daftary DK, Johnson NW, editors. Oral Diseases in the Tropics. Delhi: Oxford University Press; 1993. p. 68.
8	Susheela AK. Fluorosis: Indian Scienario: A Treatise on Fluorosis. New Delhi, India: Fluorosis Research and Rural Development Foundation; 2001.
9	Central ground water board north western region Chandigarh. Available from: http://cgwbchd.nic.in/qulhar.htm. [Last accessed 2016 Dec 6].
10	Yadav JP, Lata S, Sudhir K, Kumar S. Fluoride distribution in groundwater and survey of dental fluorosis among school children in the villages of the Jhajjar District of Haryana, India. Environ Geochem Health 2009;31:431-8.
11	Thylstrup A, Fejerskov O. Clinical appearance of dental fluorosis in permanent teeth in relation to histological changes. Community Dent Oral Epidemiol 1978;6:315-28.
12	Mabelya L, van’t Hof MA, König KG, van Palenstein Helderman WH. Comparison of two indices of dental fluorosis in low, moderate and high fluorosis Tanzanian populations. Community Dent Oral Epidemiol 1994;22:415-20.
13	Black GV, Mckay FS. Mottled teeth-An endemic developmental imperfection of the teeth heretofore unknown in the literature of dentistry. Dent COSMOS 1916;58:129-56.
14	Velazquez LNM, Fantinel LM, Ferreira EF, Castilho LS. Dental fluorosis endemism related to natural groundwater contamination by fluorine in Mid Sao Francisco basin, Minas Gerais State, Brazil. Fourth International Conference on Safe water, Rio de Janeiro. Safe Water 2006; p. 1-21.
15	Yadav KA, Khan P. Fluoride and fluorosis status in groundwater of Todarai Singh area of district Tonk (Rajasthan, India). Int J Chem Environ Pharm Res 2010;1:6-11.
16	Bhagavatula P, Levy SM, Broffitt B, Weber-Gasparoni K, Warren JJ. Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth. Community Dent Oral Epidemiol 2016;44:32-45.
17	Bharati P, Kubakabaddi A, Rao M. Clinical symptoms of dental and skeletal fluorosis in Gadag and Bagalkot districts of Karnataka. J Hum Ecol 2005;18:105-7.
18	Mamatha P, Rao MS. Geochemistry of fluoride rich in groundwater in Kolar and Tumkur districts of Karnataka. Environ Earth Sci 2010;61:131-42.
19	Dean HT. The investigation of physiological effects by the epidemiological method. In: Moulton FR, editor. Fluorine and Dental Health. Washington DC: American Association for the Advancement of Science; 1942. p. 23-32.
20	Anguilar-Díaz FC, Irigoyen-Camacho ME, Borges-Yáñez SA. Oral-health-related quality of life in schoolchildren in an endemic fluorosis area of Mexico. Qual Life Res 2011;20:1699-706.
21	Onoriobe U, Rozier R, Cantrell J, King R. Effects of enamel fluorosis and dental caries on quality of life. J Dent Res 2014;93:972-9.
22	Tellez M, Santamaria RM, Gomez J, Martignon S. Dental fluorosis, dental caries and quality of life factors among schoolchildren in a Colombian fluorotic area. Community Dent Health 2012;29:95-9.
23	Do LG, Spencer A. Oral health-related quality of life of children by dental caries and fluorosis experience. J Public Health Dent 2007;67:132-9.
24	Vuhahula EAM, Masalu JRP, Mabelya L, Wandwi WBC. Dental fluorosis in Tanzania great rift valley in relation to fluoride levels in water and in ‘Magadi’ (Trona). Desalination 2009;248:610-5.
25	Mann J, Tibi M, Sgan-Cohen HD. Fluorosis and caries prevalence in a community drinking above-optimal fluoridated water. Community Dent Oral Epidemiol 1987;15:293-5.
26	Bhalla A, Malik S, Sharma S. Prevalence of dental fluorosis among school children residing in Kanpur City, Uttar Pradesh, India. Eur J Gen Dent 2015;4:59-63.
27	Singh A, Laura JS, Rana A. Fluoride distribution in groundwater and prevalence of dental fluorosis among school children in villages of Jind district, Haryana (India). Int J Current Res 2013;5:998-1002.
28	Dahiya S, Kaur A, Jain N. Prevalence of fluorosis among school children in rural area, district Bhiwani: A case study. Indian J Environ Hlth 2000;42:192-5.
29	Khan SQ, Moheet IA, Farooq I, Farooqi FA, ArRejaie AS, Al Abbad MA, et al. Prevalence of dental fluorosis in school going children of Dammam, Saudi Arabia. J Dent Allied Sci 2015;4:69-72.
30	Kotecha PV, Patel SV, Bhalani KD, Shah D, Shah VS, Mehta KG. Prevalence of dental fluorosis and dental caries in association with high levels of drinking water fluoride content in a district of Gujarat, India. Indian J Med Res 2012;135:873-7.
31	Gupta A, Dhingra R, Chaudhuri P, Gupta A. A comparison of various minimally invasive techniques for the removal of dental fluorosis stains in children. J Indian Soc Pedod Prev Dent 2017;35:260-8.
32	Penumatsa NV, Sharanesha RB. Bleaching of fluorosis stains using sodium hypochlorite. J Pharm Bioallied Sci 2015;7(Suppl 2):S766-8.

*Original full-text article online at https://www.ijdr.in/printarticle.asp?issn=0970-9290;year=2021;volume=32;issue=1;spage=110;epage=114;aulast=Shyam