Changes in Salivary Proteome with Regard to Pain-Related Proteins Following Fixed Orthodontic Appliance Placement

Orthodontic tooth movement relies on the application of force that drives bone resorption and formation. As saliva reflects these processes and harbors proteins of diagnostic and prognostic value, we studied these changes in patients with malocclusion. This study sampled the proteomes and evaluated the intensity of experienced pain related to the apparatus placement in ten male patients with malocclusion on day 0, 30 and 60 of orthodontic therapy. A prospective shotgun proteomic pilot study identified 947 proteins, and demonstrated a shift in the salivary proteome during orthodontic therapy. Gene enrichment analysis revealed hemostasis, but also platelet activation, signaling, aggregation and degranulation as prominent processes occurring 30 days post appliance placement, while proteins related to antimicrobial resistance were detected throughout the observed tooth movement period. Our research indicated an increased expression of proteins related to the immune and protective response to foreign bodies and pathogens, cellular and tissue injury, and biomechanical stimuli associated to bone remodeling. While a direct linkage between the alteration of the proteomic profile and the direction of painful perception was not identified, all results suggest a well-coordinated yet complex occurrence involving a multitude of biologically active signaling pathways and molecules.