## 4 Discussion  
In the search for novel therapeutics approaches, this pioneering study investigated the performance of bioactive varnishes formulated with a mixture of _tt_-farnesol, quercetin, and theobromine at different concentrations in dental enamel demineralization compared to 5% NaF varnish. It is the first study to evaluate the combined compounds and their effects in relation to dental enamel mineral loss. The application of varnishes has been an accepted practice in dental routine, owing to several advantages, such as improved adherence to the enamel surface and a prolonged contact time between the varnish and the tooth [24]. Duraphat(tm) is considered the gold-standard varnish, as it is a fluoride varnish that exhibits anticaries activity, attributed to the deposition of fluorapatite on the enamel and the formation of superficial reservoirs of calcium fluoride [5; 25; 26]. The surface microhardness loss percentage serves as an indirect indicator of the enamel mineral loss that occurs after varnish application [27]. Through this percentage, it was found that enamel specimens treated with Duraphat(tm) varnish, the gold-standard fluoride varnish, showed a lower % of surface microhardness loss. Based on the results obtained, it can be observed that the experimental varnish containing bioactive did not demonstrate a preventive effect on enamel mineral loss, thus confirming the null hypothesis. The SEM images have also confirmed that the 5% NaF treatment was more effective in protecting the enamel surface from extensive mineral loss. Although the varnish was removed after a short contact time, it was initially hypothesized that its natural compounds farnesol, quercetin, and theobromine could exert a sustained protective effect on enamel due to their ability to adsorb to the tooth surface and modulate mineral availability. However, no significant remineralization was observed during pH cycling, suggesting that the exposure time, compound concentration, or delivery mode may have been insufficient to produce a measurable effect under the conditions tested. In this study, E2, besides being more concentrated, appeared noticeably more viscous than E1. Although the varnishes contained the same elements and had rosin as a base, the addition of high compound concentrations may have resulted in increased viscosity, which could have hindered flow and wettability, both important in order for exchanges between the varnish and enamel surface to occur. The addition of high concentrations may also adversely affect the properties of formulations, as the bonding of different functional groups in different configurations can impact the biological effects of flavonoids [18; 28]. Additionally, discrepancies between the experimental model and clinical practice may occur, given the amount of fluoride varnish used in clinical settings, which is difficult to control and depends on the application mode [23]. Depending on its viscosity, part of the varnish may remain on the application brush, and these amounts may vary. Therefore, conducting further studies to analyze the viscosity and wetting of these varnishes is encouraged. So far, the literature has consistently shown the effect of bioactive as anticaries therapeutic agents. [PERSON] et al. (2013) and [PERSON] et al. (2012) have shown that frequent application of theobromine to demineralized enamel surfaces promotes surface recrystallization and enhances enamel hardness more effectively than sodium fluoride [7; 29]. However, the findings of the current study do not corroborate those found by [PERSON] et al. and [PERSON] et al., and the variation in results can be understood as being due to the diversity in the evaluation methods employed. Both cited studies used human dental enamel and conducted different acid challenges.