The Impact of Fluoride on Ameloblasts and the Mechanisms of Enamel Fluorosis

Abstract

Intake of excess amounts of fluoride during tooth development cause enamel fluorosis, a developmental disturbance that makes enamel more porous. In mild fluorosis, there are white opaque striations across the enamel surface, whereas in more severe cases, the porous regions increase in size, with enamel pitting, and secondary discoloration of the enamel surface. The effects of fluoride on enamel formation suggest that fluoride affects the enamelforming cells, the ameloblasts. Studies investigating the effects of fluoride on ameloblasts and the mechanisms of fluorosis are based on in vitro cultures as well as animal models. The use of these model systems requires a biologically relevant fluoride dose, and must be carefully interpreted in relation to human tooth formation. Based on these studies, we propose that fluoride can directly affect the ameloblasts, particularly at high fluoride levels, while at lower fluoride levels, the ameloblasts may respond to local effects of fluoride on the mineralizing matrix. A new working model is presented, focused on the assumption that fluoride increases the rate of mineral formation, resulting in a greater release of protons into the forming enamel matrix.

Evaluation of Fluoride Retention Due to Most Commonly Consumed Estuarine Fishes Among Fish Consuming Population of Andhra Pradesh as a Contributing Factor to Dental Fluorosis: A Cross-Sectional Study

“…During amelogenesis, the tooth when chronically exposed to low-dose fluoride results in development of the double-response lines, formed at the secretory stage. Posteruptive defects after a single high plasma peak level of fluoride are deep and shallow pits that result from sub-ameloblastic cysts formed by damaged earlyand late-secretory ameloblasts [23].…”

Prevalence of dental fluorosis in Mexico 2005-2015: a literature review

“…In mild cases, chalky white opaque areas are observed, in moderate cases spots may be brownish, 2 and in severe cases enamel is fragile which can lead to fracture and loss of tissue. 3 DF is observed in specific geographical areas in the world 4 showing an endemic epidemiological pattern affecting millions of people; this alteration can be considered an indicator of excessive fluoride exposure.…”

Fluoride’s Effects on the Formation of Teeth and Bones, and the Influence of Genetics

“…Ameloblasts in the maturational phase appear to be the cellular target of chronic fluoride exposure (DenBesten and Thariani, 1992), whereas acute fluoride toxicity targets the transitional and early-secretory ameloblasts (Lyaruu et al, 2006). The mechanism(s) underlying DF remain obscure, but likely contribute to the observed retention of enamel matrix proteins and may include reduced removal of enamel matrix proteins during enamel maturation, perturbation of extracellular transport, or initiation of the ER stress-response pathway (Matsuo et al, 2000;DenBesten et al, 2002;Kubota et al, 2005;Sharma et al, 2008;Bronckers et al, 2009;Everett et al, 2009). While biological factors likely play critical roles in the pathogenesis of DF, physicochemical affects should also be considered (Robinson et al, 2004).…”