Proteomic profiles of the acquired enamel pellicle formed in vitro, in situ, or in vivo.

ABSTRACT

This study compared the protein profile of the acquired enamel pellicle (AEP) formed under three conditions in vitro, in situ, and in vivo. Nine volunteers participated in all procedures. In the in vitro condition, the volunteers donated saliva, in which specimens were incubated to form the AEP. In the in situ condition, the volunteers used an oral device containing specimens where the AEP was formed. In the in vivo condition, the AEP was collected from the volunteers own teeth. All AEPs were formed for 120 min, collected and processed by mass spectrometry. Overall, a total of 321 proteins were identified, among which 37 proteins are commonly considered typical in the AEP. For each of the in vitro, in situ, and in vivo conditions, respectively, 66, 174, and 170 proteins were identified. For the in vitro condition, 17 pellicle-typical proteins were not identified. Furthermore, several proteins with important functions within the AEP presented differences in expression in the three conditions. The qualitative profile of the proteins, especially the typical ones, is different in the in vitro condition. In addition, there are important quantitative differences that may interfere when attempting to extrapolate in vitro results to an in situ and in vivo condition.