Fluoride in the drinking water and dental caries experience by tooth surface susceptibility among adults

Abstract

Background Dental caries is the most prevalent non-communicable health condition globally. The surface-based susceptibility hierarchy indicates that surfaces in the same group have similar susceptibility to caries, where the most susceptible group consists of occlusal surfaces of first molars and buccal surfaces of lower first molars, and the least susceptible surfaces are smooth and proximal surfaces of first premolars, canines and incisors. Therefore, fluoride in the drinking water could impact one group more than the other group. The present study examined the association between fluoride levels in the drinking water and dental caries experience in adults in the context of varying tooth surface susceptibility. Methods Data from the cross-sectional National Lithuanian Oral Health Survey conducted in 2017–2019 included a stratified random sample of 1398 35–74-year-olds (52% response rate). Dental caries experience in dentine was measured at a surface level. The surfaces were grouped according to their caries susceptibility (group 1 being the most and group 4 the least susceptible), and dental caries experience was calculated separately for each susceptibility group, creating four outcomes. Information about explanatory variable, fluoride levels in the drinking water, was provided by the water suppliers. The questionnaire inquired about potential determinants: sociodemographic characteristics and oral health-related behaviors. Chi-square, Mann–Whitney U and Kruskal Wallis tests were used for descriptive statistics, and linear regression analyses to examine the association between fluoride levels and four outcomes. Results The proportions of median decayed, missing, filled surfaces decreased following the surface-based susceptibility hierarchy (group 1–33%, group 2–28%, group 3–24%, group 4–15%). When adjusted for potential determinants, higher-level fluoride (≥ 0.7 ppm vs < 0.7 ppm) in the drinking water associated with lower dental caries experience in all surface-based susceptibility hierarchy groups; Group 1: β = − 0.23 (95 %CI − 0.44; − 0.001), Group 2: β = − 0.44 (95 %CI − 0.82; − 0.07), Group 3: β = − 1.14 (95 %CI − 1.88; − 0.41) and Group 4: β = − 6.28 (95 %CI − 9.29; − 3.30). Conclusions The higher-level fluoride in the drinking water associated with lower dental caries experience in adults and this was observed in all surface-based susceptibility groups. However, there is a need to validate the surface-based susceptibility hierarchy in longitudinal adult studies.

Assessing Fluorosis Incidence in Areas with Low Fluoride Content in the Drinking Water, Fluorotic Enamel Architecture, and Composition Alterations

“…However, water consumption with increased an fluoride content accounts for only 40% of fluorosis cases; the remaining 60% are connected with fluoride intake from other sources [ 44 ]. The optimum level of fluoride exposure is, in fact, often exceeded due to the concurrent ingestion of fluoride ions from various sources [ 45 , 46 , 47 , 48 ].…”

The 20-Year Trends in Caries and Associated Determinants among Adults in Post-Soviet Lithuania: Repeated Cross-Sectional Studies

“…Among selected five urban and five rural areas, two urban and one rural area were from regions with high natural fluoride level in the drinking water. The 2017/2019 survey (second survey) recruited a random stratified sample of 723 individuals from 5 biggest Lithuanian cities (urban areas) and 10 randomly selected periurban/rural areas, one from each of 10 Lithuanian counties (response rate 53%) [Stangvaltaite-Mouhat et al, 2021;Stankeviciene et al, 2021]. No additional attempt was made to stratify areas by natural fluoride level in the drinking water; consequently, one urban area and one peri-urban/rural area had more than 1 ppm of natural fluoride in the drinking water.…”

Association between Carbonic Anhydrase VI Gene Copy Number Variations and Dental Caries Experience

“…In this survey, a random, stratified sample of individuals aged 35-74 years from 15 geographic locations (the 5 biggest cities and 10 randomly selected peri-urban/rural areas, one from each of the 10 Lithuanian counties) were invited to participate. More details about the LNOHS design and its sampling framework can be found elsewhere [Stangvaltaite-Mouhat et al, 2020;Stangvaltaite-Mouhat et al, 2021b;Stankeviciene et al, 2021]. Of all, 202 participants (14%) of the LNOHS sample agreed to provide their saliva samples for subsequent genetic analysis, and these subjects were generally healthy, not related, and had regular access to dental care.…”