## 4 Discussion  
The tea leaf size is an important parameter affecting the release of fluoride during tea brewing. With the increase in leaf fragmentation, the surface area through which fluoride \begin{table}
\begin{tabular}{l c c} \hline \hline \multicolumn{1}{c}{**Type of Tea**} & \multicolumn{1}{c}{**Fluoride Content (mg/L)**} & \multicolumn{1}{c}{**Standard Deviation, SD**} \\ \hline Green tea & 3.765 & 0.104 \\ \hline Pu-erh & 0.919 & 0.033 \\ \hline Pu-erh & 0.712 & 0.041 \\ \hline Pu-erh & 1.025 & 0.060 \\ \hline White tea & 1.288 & 0.052 \\ \hline White tea & 2.028 & 0.105 \\ \hline White tea & 1.422 & 0.058 \\ \hline White tea & 1.548 & 0.042 \\ \hline Black leaf tea & 3.512 & 0.089 \\ \hline Black leaf tea & 2.678 & 0.056 \\ \hline Black leaf tea & 4.858 & 0.159 \\ \hline Black leaf tea & 3.119 & 0.093 \\ \hline Black leaf tea & 1.997 & 0.060 \\ \hline Black leaf tea & 6.175 & 0.173 \\ \hline Black granulated tea & 5.594 & 0.286 \\ \hline Black granulated tea & 7.180 & 0.313 \\ \hline Black granulated tea & 6.230 & 0.174 \\ \hline Black tea in bags & 7.059 & 0.202 \\ \hline Black tea in bags & 5.196 & 0.175 \\ \hline Black tea in bags & 4.154 & 0.156 \\ \hline Black tea in bags & 6.300 & 0.340 \\ \hline Black tea in bags & 7.960 & 0.237 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._  
Figure 3: Mean and SD fluoride concentration (mg/L) in the tea groups. Different letters (a, b, c, etc.) show a significant difference with \(p<0.05\). extraction can occur increases, probably accelerating their transition to the infusion. To our knowledge, no studies have been published describing the exact effect of tea leaf size on fluoride content in the infusion. [PERSON] et al. [21] published a study showing that the average fluoride concentration in infusions prepared from fragmented tea leaves was higher than that of unfragmented tea leaves. In this study, significant differences in leaf size were observed in the unfragmented tea samples (average 17.7 \(\pm\) 12.2 mm; range 0.6-41.1 mm), and the particle size of the fragmented tea samples was smaller, 0.4-0.6 mm. Similar conclusions were reached by [PERSON] et al. [44], who found that fluoride leaching is the lowest in the case of leaf tea compared to powdered tea, but they did not precisely characterize the size of the tea leaves used to prepare the infusion. [PERSON] et al. [44] researched the effect of brewing time (2, 4, 6, 8, and 10 min) on the fluoride content in the infusion. They showed that after 6 min of brewing, the fluoride content reaches its maximum. Our results indicate that increasing the brewing time from 6 to 10 min further increases the fluoride content in the infusion. These observations are consistent with the data presented in the literature [21; 28; 38; 39; 45]. [PERSON] et al. [28] examined the effect of brewing time on fluoride content in the 2, 10, and 30-min range. They showed that most of the fluoride was extracted into the tea infusion after 10 min because they did not observe significant differences in the fluoride content between 10 and 30 min of infusion time. [PERSON] et al. [46] showed that the fluoride content in tea indicates its quality. They observed significant negative correlations between the content of fluoride and the content of total polyphenols and amino acids. Older tea leaves containing more fluoride are used to produce lower-quality teas, such as tea in bags and granules. Studies by [PERSON] et al. [39] and [PERSON] et al. [38] showed that significantly higher fluoride content was found in black tea infusions made from bags than from leaves. On the other hand, [PERSON] et al. [47] found that the fluoride content in leaf tea infusions is higher than in tea in bags. Due to the high variability of the fluoride content in tea leaves resulting from many factors (place of cultivation, rainfall, plant genetics, etc.) and various tea brewing conditions (time, tea weight to water volume ratio, and form of tea), the fluoride content in the infusion may be within a wide range.