## 4 Discussion  
The appropriate daily intake of F varies based on age and body weight, similar to other nutrients [3; 6]. When used and consumed appropriately, F is considered safe and has preventive effects against dental caries [6; 25]. Dietary reference intakes for F have been established by the Food and Nutrition Board of the U.S. Institute of Medicine since 1997 [11]. These reference intakes encompass all sources of F, including fluoridated water, foods, beverages, fluoride dental products, and dietary fluoride supplements. The optimal dose is set at 0.05 mg F/kg bw/day [6; 12; 26]. Additionally, to prevent DF and potential adverse effects associated with high doses of F, a tolerable upper intake level of 0.1 mg F/kg bw/day has been established [6]. Thus, for children aged up to 6 years who are most susceptible to developing DF, the recommended adequate daily intake of F is set as follows [6; 11; 12]:  
* Infants 0-6 months (weighing approximately 7 kg): 0.01 mg/day;
* Infants 7-12 months (weighing approximately 9 kg): 0.5 mg/day;
* Children 1-3 years (weighing approximately 13 kg): 0.7 mg/day;
* Children 4-8 years (weighing approximately 22 kg): 1.0 mg/day. As mentioned earlier, exceeding the recommended daily doses of F during critical stages of amelogenesis can result in DF [2]. Clinically, teeth affected by DF may exhibit a range of manifestations. These can vary from thin white lines at the incision edge to more prominent and thicker white lines, patchy cloudy areas, yellow or light brown discoloration and even eruption pits [11]. Additionally, severe DF can result in compromised tooth strength due to poorly mineralised deeper enamel, leading to chipping and brown staining [2; 11]. While mild DF may offer some resistance to dental decay due to higher F levels, severely fluorosed teeth are more susceptible to decay due to surface irregularities or loss of the protective layer [11]. Moreover, excessive F intake has been associated with other health issues, including skeletal fluorosis, neurological toxicity, endocrine disruption and a potential decrease in IQ when exposed during prenatal and/or early life stages [21]. The fluoridation of community drinking water for the purpose of preventing tooth decay is considered one of the ten most important achievements in the field of public health in the 20 th century in the U.S. and other countries worldwide [2; 9; 11]. However, despite the decrease in the prevalence of dental caries, there has been an increase in DF worldwide [27]. The prevalence of DF in adolescents aged 12-15 years in the U.S. has increased from 23% to 41%, almost doubling since 1987 [17]. Conversely, in the population of Western Europe, only 3% consumes artificially or naturally fluoridated water [28]. Ireland has the highest proportion, with a rate of 73%, followed by Spain at 11%, the United Kingdom (UK) at 10% and Serbia at 3% [28]. Data on the prevalence of DF at the European level are inconsistent due to the use of different clinical indices and evaluation methods. According to [PERSON] et al. [29], who utilised the standardised photo evaluation method and the Thylstrup & Fejerskov (TF) index, the prevalence of DF ranges from 5% to 30% in different countries. The specific prevalence rates are as follows: Ireland at 30%, Holland at 26%, Iceland at 21%, the UK at 17%, Greece at 12%, Finland at 8% and Portugal at 5%. There is no national program for the fluoridation of drinking water in Romania, and as far as we know, there is no updated information regarding the prevalence of DF. However, in a specific region, namely the Danube Delta Biosphere Reserve, a prevalence of 2% has been reported in children between the ages of 6 and 12, and 7.42% in adults aged 18-50 [30]. A significant portion of the EU population prefers bottled water as their primary source of hydration [8; 31]. Recent statistics indicate that bottled water accounts for 48% of the market share among other non-alcoholic beverages [31].