Abstract The objective of this study was to compare the protein profile of the acquired enamel pellicle (AEP) formed in vivo in patients with or without gastroesophageal reflux disease (GERD), and with or without erosive tooth wear (ETW). Twenty-four volunteers were divided into 3 groups: 1) GERD and ETW; 2) GERD without ETW; and 3) control (without GERD). The AEP formed 120 min after prophylaxis was collected from the lingual/palatal surfaces. The samples were subjected to mass spectrometry (nLC-ESI-MS/MS) and label-free quantification by Protein Lynx Global Service software. A total of 213 proteins were identified, or 119, 92 and 106 from each group, respectively. Group 2 showed a high number of phosphorylated and calcium-binding proteins. Twenty-three proteins were found in all the groups, including 14-3-3 protein zeta/delta and 1-phosphatidylinositol. Several intracellular proteins that join saliva after the exfoliation of oral mucosa cells might have the potential to bind hydroxyapatite, or participate in forming supramolecular aggregates that bind to precursor proteins in the AEP. Proteins might play a central role in protecting the dental surface against acid dissolution.

ABSTRACT A/J and 129P3/J mice strains have been widely studied over the last few years because they respond quite differently to fluoride (F) exposure. 129P3/J mice are remarkably resistant to the development of dental fluorosis, despite excreting less F in urine and having higher circulating F levels. These two strains also present different characteristics regardless of F exposure. Objective In this study, we investigated the differential pattern of protein expression in the liver of these mice to provide insights on why they have different responses to F. Material and Methods Weanling male A/J and 129P3/J mice (n=10 from each strain) were pared and housed in metabolic cages with ad libitum access to low-F food and deionized water for 42 days. Liver proteome profiles were examined using nLC-MS/MS. Protein function was classified by GO biological process (Cluego v2.0.7 + Clupedia v1.0.8) and protein-protein interaction network was constructed (PSICQUIC, Cytoscape). Results Most proteins with fold change were increased in A/J mice. The functional category with the highest percentage of altered genes was oxidation-reduction process (20%). Subnetwork analysis revealed that proteins with fold change interacted with Disks large homolog 4 and Calcium-activated potassium channel subunit alpha-1. A/J mice had an increase in proteins related to energy flux and oxidative stress. Conclusion This could be a possible explanation for the high susceptibility of these mice to the effects of F, since the exposure also induces oxidative stress.