Role of brick tea with low-fluoride level in prevention of tea type fluorosis

Abstract

Objective To investigate the effect of drinking brick tea with low-fluoride level on prevention of tea type fluorosis.Methods Handahangacha,Hadayinggegacha,Dalainuoyi town,in Keshiketengqi Inner Mongolia endemic fluorosis area were selected as test points,and brick tea with fluoride [(204.5 ± 10.2),(308.2 ±15.4)mg/kg] was given for 12 months.Dental fluorosis,clinical skeletal fluorosis,and X-ray diagnosis of skeletalfluorosis [according to “Endemic Skeletal Fluorosis Diagnostic Criteria” (WS 192-2008)] of adults 20 to 70 years of age were examined and level of fluoride before and after the prevention trial,in brick tea,drinking water,milk tea and urine were tested (fluoride ion selective electrode method),and fluoride intake through tea was calculated.Results Detection rate of adult dental fluorosis in Handahangacha was 68.89％ (62/90),clinical detection of skeletal fluorosis was 55.32％ (52/94),and X-ray detection of skeletal fluorosis was 65.17％ (58/89); adult dental fluorosis detection rate in Hadayinggegacha was 54.84％(51/93),clinical detection of skeletal fluorosis was 65.69％(67/102),and X-ray detection rate of skeletal fluorosis was 61.36％ (54/88).Brick tea fluoride was (831.4 ±138.9),(864.3 ± 134.6)mg/kg before the prevention trial in Handahangacha and Hadayinggegacha,respectively,drinking water fluoride content was (0.27 ± 0.05),(0.54 ± 0.24)mg/L,fluoride content of milk tea was (216 ± 1.12),(2.82 ± 1.38)mg/L,adult urine fluoride content was (2.78 ± 1.57),(2.96 ± 1.80)mg/L,and fluoride intake through milk tea was (8.12 ± 5.84),(6.42 ± 5.04)mg/d,respectively; after the prevention trial the fluoride content of brick tea was (204.5 ± 10.2),(308.2 ± 15.4)mg/kg,fluoride content of drinking water (0.34 ± 0.11),(0.62 ± 0.30)mg/L,fluoride content of milk tea(0.97 ± 0.33),(1.83 ± 0.66)mg/L,fluoride content in urine(1.29 ± 0.55),( 1.47 ±0.62)mg/L,fluoride intake through milk tea (3.45 ± 2.05),(3.71 ± 2.07)mg/d,respectively; in Handahan and Hadayinggegacha after the prevention trial the fluoride in brick tea,milk tea,urine fluoride,and fluoride intake through milk tea was significantly lower than that before the trial (t =14.30,12.97 ;6.46,3.95;6.69,5.72;6.27,3.57,all P ＜ 0.01 ).Fluoride intake in Handahangacha through milk tea was within the state heath standard limits( ＜ 3.5mg/d).Conclusion Drinking low-fluoride brick tea can prevent drinking brick tea type fluorosis,the preventive effect is especially more reliable with low fluoride brick tea (204.5 ± 10.2)mg/kg. Key words: Fluoride poisoning; Intervention studies; Outcome assessment