Probe on the biomarker to substitute the dental fluorosis for deriving fluoride threshold by animal study

Abstract

Dental fluorosis had been used for deriving the fluoride acceptable threshold for a long time. However, it was diagnosed on the color or defect degree of tooth, like Dean’s Index, which would be easily influenced by lifestyle, like smoking and drinking tea. Hence, some biomarkers had already tried to assess the fluoride exposure risk with the development of bio-monitor technique, and this paper probed on an available biomarker, which based on a systematic biochemical indicator group relating to different biological function from animal experiment, to take place the old one. The experiment animals had been treated with different levels of NaF, and biochemical indicators were analyzed after three months later. The correlations between changes of biochemical indicators and the exposure levels were analyzed subsequently, and a comprehensive indicator was developed. Both the NOAEL/LOAEL and the Benchmark Dose approach were applied in this article to derive the suitable threshold and for indicator comparison. Our findings indicated that a better dose-response relationship was shown between the comprehensive indicator and exposure dose (R=0.811, R square=0.657) than single indicator (R<0.4, R square<0.2) and Dean’s Index (R=0.737, R square= 0.543). Furthermore, the available threshold of the comprehensive indicator was 1.70 mg/(kg.d) lower than it from dental fluorosis (2.00 mg/(kg.d)) which can protect animals from fluoride damage at rather low exposure level. Even the scientificity of the comprehensive indicator should be verified in further epidemiology research, its advantage can’t be ignored that it cannot only avoid the personally error during clinical diagnosis, but also present a new method to quantize the gap risk from dental fluorosis to skeletal fluorosis for those people cannot be diagnosed by dental fluorosis clinically.