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Kim, Jung, Kim, Jun, Kim, Kim, Han, Jeong, and Kim: Cost-benefit analysis of a water fluoridation program for 11 years in Jinju, Korea
Original Article

J Korean Acad Oral Health 2014;38(2):118-128.

Published online: 12 June 2014

DOI: https://doi.org/10.11149/jkaoh.2014.38.2.118

Cost-benefit analysis of a water fluoridation program for 11 years in Jinju, Korea

Man-Kyong Kim1, Ji-In Jung1, Min-Ji Kim1, Eun-Joo Jun1, Han-Na Kim1, Se-Yeon Kim1, Dong-Hun Han2, Seung-Hwa Jeong1, Jin-Bom Kim1

1Department of Preventive and Community Dentistry, Pusan National University School of Dentistry, Yangsan, Korea

2Department of Preventive and Social Dentistry, Seoul National University School of Dentistry, Seoul, Korea

Corresponding Author: Jin-Bom Kim Department of Preventive and Community Dentistry, Pusan National University School of Dentistry, 49 Busandaehak-ro, Mulgeum-eup, Yangsan 626-870, Korea Tel: +82-51-510-8223 Fax: +82-51-510-8221 E-mail: jbomkim@pusan.ac.kr

Received 3 June 2014       Revised 16 June 2014       Accepted 19 June 2014

Copyright © 2014 Journal of Korean Academy of Oral Health

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives

The aim of this study was to estimate the economic costs and benefits of a water fluoridation program in the city of Jinju, Korea.

Methods

In 2009, dental surveys were conducted on 2,315 children aged 6-12 years in Jinju, which had been fluoridated for 11 years. The decayed/missing/filled teeth (DMFT) scores of children in Jinju were compared to the DMFT scores of same-aged children in non-fluoridated small- and medium-sized cities in the fourth Korean National Health and Nutrition Examination Survey conducted from 2007 to 2009 by the Korea Centers for Disease Control and Prevention. The reduced number of decayed permanent teeth by the water fluoridation program was estimated as the difference between the DMFT scores of children in Jinju and those in non-fluoridated small- and medium-sized cities. The economic benefits were estimated by the savings from reduced dental treatment costs by using the reduced number of decayed permanent teeth from the water fluoridation program. All annual costs and benefits were calculated from 1998 to 2009. The social rate and untreated rate of decayed teeth were applied as 3% and 20%, respectively. The annual benefit-cost ratio was estimated by using the annual benefits and cumulative program costs.

Results

The economic benefit in 2009 from a water fluoridation program was estimated as 57,496,000,000 Korean Won (KRW), and the cumulative cost in 2009 was estimated as 1,387,000,000 KRW. The net present value in 2009 from a water fluoridation program was 56,109,000,000 KRW. The benefit-cost ratio in 2009 was estimated as 41.4.

Conclusions

The economic benefit of a water fluoridation program in Jinju city was evaluated as excellent.

Keywords: Benefit, Cost, Dental caries, DMFT index, Fluoridation, Prevention

References

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Fig. 1.
Estimated cumulative cost and benefit from water fluoridation program in Jinju at the assumption of 20% untreated rate.
jkaoh-38-118f1.tif
Fig. 2.
Estimated benefit and cost ratio (B/C ratio) in 2009 from water fluoridation program in Jinju at the assumption of untreated rate, 0%, 20%, 30%; social discount rate, 2%, 3%, 5%.
jkaoh-38-118f2.tif
Table 1.
Number of surveyed children for DMFT scores
Age Jinju Control*
Total 2,315 791
6 302 105
7 341 118
8 314 131
9 313 104
10 324 111
11 344 109
12 377 113

*Surveyed children living in downtown (dong) districts of small and medium cities at the Fourth Korea National Health and Nutrition Examination Survey in 2007-2009 conducted by Korea Center for Disease Control and Prevention.

Table 2.
Estimated cost of water fluoridation program in Jinju*
Year Total Fluoride feeder amortization† Purchase cost Fluoride feeder repair cost Program evaluation cost
Fluoride chemical Fluoride level test reagent Component of fluoride level test kit
All 1,195,871 443,965 527,306 50,264 14,883 82,453 77,000
1997 12,000 - - - - - 12,000
1998 85,461 27,150 50,282 3,029 - - 5,000
1999 81,861 27,150 40,705 2,145 4,455 2,406 5,000
2000 79,270 27,150 40,471 2,027 941 3,680 5,000
2001 80,583 27,150 42,900 3,392 1,426 715 5,000
2002 81,035 27,150 42,511 2,888 2,243 1,243 5,000
2003 94,820 27,150 51,890 6,314 2,233 2,233 5,000
2004 83,351 27,150 33,590 3,395 1,726 12,490 5,000
2005 78,870 27,150 14,442 3,395 1,859 27,024 5,000
2006 64,865 29,262 - 15,610 - 14,993 5,000
2007 143,670 65,833 67,667 990 - 4,180 5,000
2008 154,162 65,833 76,248 7,080 - - 5,000
2009 155,923 65,833 66,600 - - 13,490 10,000

*Thousand Korean Won.

† Annual amortization included the cost of new fluoride feeder design in 2006-2009.

Table 3.
Population of tap water supply by year
Age 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
6 4,387 4,473 4,347 4,220 4,093 3,966 3,840 3,666 3,540 3,364 3,187
7 4,479 4,625 4,561 4,497 4,433 4,369 4,305 4,067 3,881 3,639 3,397
8 4,440 4,503 4,498 4,493 4,488 4,483 4,478 4,232 4,042 3,793 3,544
9 4,381 4,392 4,423 4,455 4,487 4,519 4,550 4,375 4,258 4,080 3,902
10 4,326 4,317 4,416 4,516 4,616 4,716 4,816 4,689 4,626 4,497 4,369
11 4,430 4,265 4,336 4,407 4,477 4,548 4,619 4,497 4,436 4,312 4,189
12 4,479 4,206 4,314 4,421 4,529 4,637 4,745 4,693 4,706 4,655 4,603

Note 1. Tap water supply rate (%) was 93.9% in 2006 and 95.2% in 2007. 2. Tap water supply rate (%) from 1997 to 2005 was assumed as same as 2006. 3. Tap water supply rate (%) from 2008 to 2009 was assumed as same as 2007.

Table 4.
Reduction value of DMFT index in Jinju compared to control
Age DMFT index Reduced value (C)*
Control (A) Jinju (B)
6 0.08 0.04 0.04
7 0.39 0.17 0.22
8 0.71 0.37 0.34
9 1.01 0.62 0.39
10 1.02 0.70 0.32
11 1.60 0.94 0.66
12 1.80 1.43 0.37

*C=B-A.

Table 5.
Estimation of reduced DMFT index* and total reduced DMFT scores† by year
Age 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Reduced DMFT index*
6 0.00 0.01 0.01 0.01 0.02 0.02 0.03 0.03 0.03 0.04 0.04
7 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22
8 0.03 0.06 0.09 0.12 0.15 0.19 0.22 0.25 0.28 0.31 0.34
9 0.04 0.07 0.11 0.14 0.18 0.21 0.25 0.28 0.32 0.35 0.39
10 0.03 0.06 0.09 0.12 0.15 0.17 0.20 0.23 0.26 0.29 0.32
11 0.06 0.12 0.18 0.24 0.30 0.36 0.42 0.48 0.54 0.60 0.66
12 0.03 0.07 0.10 0.13 0.17 0.20 0.24 0.27 0.30 0.34 0.37
Total number of reduced DMFT†
6 16 33 47 61 74 87 98 107 116 122 127
7 90 185 274 360 443 524 603 651 699 728 747
8 137 278 417 555 694 831 969 1,047 1,124 1,172 1,205
9 155 311 470 632 795 961 1,129 1,241 1,359 1,447 1,522
10 126 251 385 526 671 823 981 1,091 1,211 1,308 1,398
11 266 512 780 1,058 1,343 1,637 1,940 2,159 2,395 2,587 2,764
12 151 283 435 595 762 936 1,117 1,263 1,425 1,566 1,703

*The amount of reduced DMFT index was estimated as same every year for 11 years since the initiation of water fluoridation program in 1998.

† Reduced value of DMFT index by age × population of tap water supply by age.

Table 6.
Dental filling rate (%) in 2009 by material*
Age Number of filling surfaces Amalgam (%)† Composite resin (%) Gold inlay (%)
Mean SD Mean SD Mean SD
6 14 20.0 44.72 80.00 44.72 0.00 0.00
7 76 16.7 37.90 81.67 38.24 1.67 9.13
8 139 19.2 39.80 78.85 41.24 1.92 13.87
9 236 28.3 44.00 68.53 45.74 3.17 15.68
10 269 31.5 45.96 65.24 46.75 3.28 15.92
11 420 36.7 47.32 57.85 48.65 5.49 22.06
12 707 30.0 42.43 61.79 44.55 8.18 24.15

*Results from 2009-year dental survey in Jinju.

† The number of filled teeth with other materials except for amalgam, light-cured composite resin and gold inlay were included in the number of filled teeth with amalgam as the highest filling rate with other materials was 3.33% at age 7.

Table 7.
Percentage estimation of filled teeth with amalgam* and light-cured composite resin† among all filled teeth by year
Age 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
% filled teeth with amalgam*
6 100.0 92.0 84.0 76.0 68.0 60.0 52.0 44.0 36.0 28.0 20.0
7 98.3 90.2 82.0 73.8 65.7 57.5 49.3 41.2 33.0 24.8 16.7
8 98.1 90.2 82.3 74.4 66.5 58.7 50.8 42.9 35.0 27.1 19.2
9 96.8 90.0 83.1 76.3 69.4 62.6 55.7 48.9 42.0 35.2 28.3
10 96.7 90.2 83.7 77.1 70.6 64.1 57.6 51.1 44.5 38.0 31.5
11 94.5 88.7 82.9 77.2 71.4 65.6 59.8 54.0 48.2 42.4 36.7
12 91.8 85.6 79.5 73.3 67.1 60.9 54.7 48.6 42.4 36.2 30.0
% filled teeth with light-cured composite resin†
6 0.0 8.0 16.0 24.0 32.0 40.0 48.0 56.0 64.0 72.0 80.0
7 0.0 8.2 16.3 24.5 32.7 40.8 49.0 57.2 65.3 73.5 81.7
8 0.0 7.9 15.8 23.7 31.5 39.4 47.3 55.2 63.1 71.0 78.9
9 0.0 6.9 13.7 20.6 27.4 34.3 41.1 48.0 54.8 61.7 68.5
10 0.0 6.5 13.0 19.6 26.1 32.6 39.1 45.7 52.2 58.7 65.2
11 0.0 5.8 11.6 17.4 23.1 28.9 34.7 40.5 46.3 52.1 57.9
12 0.0 6.2 12.4 18.5 24.7 30.9 37.1 43.3 49.4 55.6 61.8

*All dental filling materials except for light-cured composite resin and gold inlay in 1999 were conservatively assumed to be amalgam. A same amount of filling rate with amalgam was estimated to be reduced every year from 1999 to 2009.

† The light-cured composite resin not covered by national health insurance was conservatively assumed not to be used as dental filling material in 1999. A same amount of filling rate with light-cured composite resin was estimated to increase every year from 1999 to 2009.

Table 8.
Fees of filling treatments per tooth by material and year (thousand KRW)
Material Age 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Amalgam <8 20,210 20,410 28,720 28,710 29,260 30,320 31,200 32,280 33,120 33,410 32,990
8-12 17,870 19,500 24,230 24,340 24,760 25,690 26,450 27,250 28,080 27,640 27,930
Light-cured composite resin 6-12 55,000 57,500 60,000 62,500 65,000 67,500 70,000 72,500 75,000 77,500 80,000
Gold inlay 6-12 238,334 247,501 256,668 265,835 275,002 284,169 293,336 302,503 311,670 320,837 330,000

Note. 1. In the estimation of fees for fillings with amalgam covered by national health insurance, number of filled teeth was assumed to be same at upper and lower dentition. Rate of one or twosurface among filled teeth was assumed as same (Reference. Kim JB and Kim JB, 1988).2. Dental filling fees with light-cured composite resin or gold inlay not covered by health insurance were surveyed from general dental practitioners at Jinju in 1998 and 2009. A same amountof fees was assumed to change every year from 1999 to 2009.3. KRW, Korean Won.

Table 9.
Estimation of total savings from filling treatments (million KRW)
Age 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
6 26 61 128 181 242 313 390 468 555 638 720
7 171 403 824 1,179 1,597 2,086 2,632 3,112 3,640 4,112 4,564
8 243 598 1,146 1,689 2,345 3,135 4,044 4,815 5,678 6,439 7,209
9 309 731 1,374 2,014 2,782 3,707 4,772 5,726 6,825 7,833 8,910
10 253 592 1,126 1,670 2,335 3,148 4,100 4,972 5,995 6,964 8,031
11 637 1,401 2,568 3,741 5,137 6,808 8,725 10,480 12,525 14,426 16,506
12 433 917 1,660 2,435 3,362 4,473 5,758 7,006 8,488 9,939 11,555

Note. 1. The untreated rate of total decayed teeth was assumed as 20%. 2. Total savings from filling treatments were estimated using total number of reduced DMFT and filling fees. 3. KRW, Korean Won.

Table 10.
Estimation of converted cost to present value in 2009 required at water fluoridation program
Year Annual total cost* Converted cost to present value (thousand KRW)†
Annual cost Annual cumulative cost
1997 12,000 17,109 17,109
1998 85,461 118,298 135,408
1999 81,861 110,014 245,422
2000 79,270 103,429 348,851
2001 80,583 102,081 450,931
2002 81,035 99,662 550,593
2003 94,820 113,221 663,814
2004 83,351 96,627 760,441
2005 78,870 88,769 849,210
2006 64,865 70,879 920,089
2007 143,670 152,419 1,072,508
2008 154,162 158,787 1,231,295
2009 155,923 156,923 1,387,218

*Sum of annual fluoride feeder amortization and purchase cost of fluoride chemical and reagent to check the fluoride level and others.

† Converted present value in 2009 using 3% of social discount rate.

Table 11.
Benefit cost ratio (B/C ratio) from water fluoridation program
Age Present value in 2009 (million KRW) B/C ratio (R)
Benefit (B) Cumulative cost (C) Net present value (NPV)
1997 17 ―17 -
1998 135 ―135 -
1999 2,783 245 2,538 11.3
2000 6,136 349 5,787 17.6
2001 11,179 451 10,728 24.8
2002 15,876 551 15,325 28.8
2003 21,256 664 20,592 32.0
2004 27,441 760 26,681 36.1
2005 34,239 849 33,390 40.3
2006 39,970 920 39,050 43.4
2007 46,368 1,073 45,295 43.2
2008 51,859 1,231 50,628 42.1
2009 57,496 1,387 56,109 41.4

Note 1. R=B/C, 2. NPV=B-C, 3. Benefit was estimated at the assumption of the untreated rate, 20%; social discount rate, 3%.

Table 12.
Benefit cost ratio (B/C ratio) at the assumption of 0%, 20% and 30% untreated rate (million KRW)
Year 2%* 3%* 5%*
Benefit (B) Cum. cost† (C) B/C ratio Benefit (B) Cum. cost† (C) B/C ratio Benefit (B) Cum. cost† (C) B/C ratio
0% untreated rate
1999 3,156 221 14.3 3,479 245 14.2 4,217 301 14.0
2000 7,025 316 22.2 7,669 349 22.0 9,119 424 21.5
2001 12,925 410 31.5 13,974 451 31.0 16,298 543 30.0
2002 18,535 504 36.8 19,845 551 36.0 22,705 657 34.6
2003 25,059 610 41.1 26,569 664 40.0 29,819 784 38.0
2004 32,669 702 46.5 34,302 760 45.1 37,764 891 42.4
2005 41,160 788 52.3 42,798 849 50.4 46,221 986 46.9
2006 48,521 857 56.6 49,962 920 54.3 52,929 1,062 49.9
2007 56,840 1,006 56.5 57,960 1,073 54.0 60,233 1,220 49.4
2008 64,195 1,163 55.2 64,824 1,231 52.6 66,083 1,382 47.8
2009 71,870 1,319 54.5 71,870 1,387 51.8 71,870 1,538 46.7
20% untreated rate
1999 2,525 221 11.4 2,783 245 11.3 3,374 301 11.2
2000 5,620 316 17.8 6,136 349 17.6 7,295 424 17.2
2001 10,340 410 25.2 11,179 451 24.8 13,039 543 24.0
2002 14,828 504 29.4 15,876 551 28.8 18,164 657 27.6
2003 20,047 610 32.8 21,256 664 32.0 23,855 784 30.4
2004 26,135 702 37.2 27,441 760 36.1 30,211 891 33.9
2005 32,928 788 41.8 34,239 849 40.3 36,976 986 37.5
2006 38,817 857 45.3 39,970 920 43.4 42,343 1,062 39.9
2007 45,472 1,006 45.2 46,368 1,073 43.2 48,187 1,220 39.5
2008 51,356 1,163 44.1 51,859 1,231 42.1 52,866 1,382 38.3
2009 57,496 1,319 43.6 57,496 1,387 41.4 57,496 1,538 37.4
30% untreated rate
1999 2,209 221 10.0 2,435 245 9.9 2,952 301 9.8
2000 4,917 316 15.6 5,369 349 15.4 6,383 424 15.1
2001 9,047 410 22.0 9,782 451 21.7 11,409 543 21.0
2002 12,974 504 25.8 13,892 551 25.2 15,893 657 24.2
2003 17,541 610 28.7 18,599 664 28.0 20,873 784 26.6
2004 22,868 702 32.6 24,011 760 31.6 26,435 891 29.7
2005 28,812 788 36.6 29,959 849 35.3 32,354 986 32.8
2006 33,965 857 39.7 34,973 920 38.0 37,050 1,062 34.9
2007 39,788 1,006 39.6 40,572 1,073 37.8 42,163 1,220 34.6
2008 44,936 1,163 38.6 45,377 1,231 36.9 46,258 1,382 33.5
2009 50,309 1,319 38.1 50,309 1,387 36.3 50,309 1,538 32.7

*Social discount rate.

† Cumulative cost.

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