Gingival crevicular fluid and its immune mediators in the proteomic era

The discovery of biomarkers for periodontal disease requires an in-depth understanding of the molecular basis of the initiation and progression of the disease. The gingival crevicular fluid is a biological medium suitable for identifying and measuring such biomarkers because it can be easily and noninvasively sampled from the immediate vicinity of the affected tissues. An ever-expanding pool of gingival crevicular fluid proteins associated with periodontal health or disease has been catalogued over the years, particularly with the recent implementation of proteomic technologies. 'Proteomics' refers to the large-scale study of entire arrays of proteins expressed by a genome and present in a cell, tissue, biological fluid or organism. Hence, such technologies provide a broad qualitative and quantitative insight of the proteins present in gingival crevicular fluid. Pertinent studies have amassed on the information gathered to date on protein signatures in periodontal health and disease, and have confirmed the nature of the immunological host response. This review discusses the application of proteomic technologies in characterizing the molecular networks present in gingival crevicular fluid, their potential for discovery of biomarkers that are meaningful for clinical practice, and the associated technical challenges.