Salivary Proteomics and Orthodontic Tooth Movement

Objectives: The primary objective of the study was to implement unbiased, label-free proteomics analysis to whole human saliva. The secondary objective was to determine significant protein expression changes following the usage of the intra-oral vibration device.
Methods: In this prospective study, four volunteer participants were advised to use an intra-oral vibration device 10 mins/day for 30 days. Whole salivary samples were collected at 0 days, 15 days, and 30-days. All samples were centrifuged at 13,000 rpm at 4^oC for 30 minutes, and the supernatant was collected and stored at -80^oC for further analysis. BCA assay was performed to quantify the protein content, which was utilized for sample preparation (Cys reduction, alkylation, tryptic digestion, and peptide desalting). An equimolar aliquot of each sample was analyzed using nanoflow ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. All raw files were searched against the Uniprot human proteome database using the Andromeda search engine and peptide/protein quantitation was performed by MaxQuant (v1.6.1.0).
Results: A total of 444 proteins (2 peptides minimum) were identified from all samples while 373 proteins were common for all 3-time points. Ten proteins (APOH, VTN, FGA, ANXA1, OLFM4, SERPING1, PIP, APOA1, CALU, TMSB4X) showed statistically significant downregulation from 0 to 30 days (ANOVA, P <0.05). Gene enhancement analysis was also performed to look for the processes involving identified proteins.
Conclusions: Salivary proteomics can be utilized as a potential tool in the evaluation of the progress of orthodontic treatment and can collaborate with various interventions associated with accelerated orthodontic to evaluate their efficiency.