TECHNICAL BRIEF www.clinical.proteomics-journal.com Salivary Fingerprinting of Periodontal Disease by Infrared-ATR Spectroscopy Kerstin Meta-Catherina Beyer-Hans, Markus Werner Sigrist,* Angelika Silbereisen, Veli Ozgen Ozturk, Gulnur Emingil, and Nagihan Bostanci* Purpose: Periodontal diseases, the most common chronic inflammatory diseases in humans, do not only affect tooth-supporting tissues but also other body parts by contributing to the development of life-threatening conditions. Since currently available diagnostic methods in periodontics lack the ability to identify patients at high risk for periodontal disease progression, development of innovative, non-invasive, rapid detection methods for diagnosing periodontal diseases is needed. This study aims to assess the potential of infrared attenuated total reflection (IR-ATR) spectroscopy to detect differences in composition of saliva supernatant in non-periodontitis individuals (control) and patients with generalized aggressive periodontitis (G-AgP). Experimental Design: IR-ATR is performed with a wavelength interval from 1230 to 1180 cm -1 , analyzed with a simple subtraction in absorbance data. Results: Ten samples show in the analysis of variance of the two data sets a true difference (99.8%). A principal component analysis (PCA) is able to discriminate between G-AgP and control groups. Conclusion and Clinical Relevance: This study demonstrates for the first time that IR-ATR spectroscopy is a promising tool for the analysis of saliva supernatant for the diagnosis of periodontitis, and potentially other periodontal conditions. IR-ATR spectroscopy holds the potential to be miniaturized and utilized as a non-invasive screening test. Periodontal diseases are the most common chronic inflam- matory diseases in humans, and affect the tooth-supporting tissues. Moreover, recent evidence has indicated that periodontal diseases could contribute to the development of life-threating conditions. [1,2] Of the several forms of periodontitis, gener- alized aggressive periodontitis (G-AgP) is the most severe, Dr. K. M.-C. Beyer-Hans [+] , Prof. M. W. Sigrist Laser Spectroscopy and Sensing Lab Institute for Quantum Electronics ETH Zurich, Zurich 8093, Switzerland E-mail: sigristm@phys.ethz.ch Dr. V. O. Ozturk Department of Periodontology School of Dentistry Adnan Menderes University Aydin 09100, Turkey [+] Present address: Swiss Nanoscience Institute, University of Basel, Basel 4056, Switzerland DOI: 10.1002/prca.201900092 characterized by early age of on- set and rapid destruction of the pe- riodontal tissues in otherwise healthy individuals. [3] Although G-AgP is com- paratively rare in the general population (0.1–5%), [3] there is a need for under- standing the causes of its premature de- velopment, and for establishing early di- agnosis methods, before tissue break- down occurs and the obvious clinical and radiographic signs are present. [4] A noninvasive, periodontal probing-free platform is needed for early identifi- cation, monitoring, and prediction of the disease. In this respect, saliva has shown to be a useful reservoir for clin- ically relevant microbiological and pro- tein biomarkers, for reflection of pe- riodontal conditions. [5–7] Several meth- ods have been used in the analysis of saliva, including immunoassays, colori- metric methods, and most recently quan- titative mass spectrometric methods. [8–10] However, these assays are quite labori- ous and cannot be suitably modified for simplified chair-side analysis. [11] Optical spectroscopic methods like fluorescence spectroscopy, Raman spectroscopy, and infrared attenuated total reflection (IR-ATR) spectroscopy have been applied for the characterization of body fluids and tissue samples. [12–16] IR-ATR offers enhanced sensitivity, faster acquisition times, and higher resolution capacity and needs only minimal or no sample pretreatment. [15,17–19] Even though advances have been observed Prof. G. Emingil Department of Periodontology Faculty of Dentistry Egg University Izmir 35100, Turkey Dr. A. Silbereisen, Prof. N. Bostanci Section of Periodontology and Dental Prevention Division of Oral Diseases Department of Dental Medicine Karolinska Institutet Huddinge 14152, Stockholm, Sweden E-mail: nagihan.bostanci@ki.se Proteomics Clin. Appl. 2020, 14, 1900092 © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1900092 (1 of 4)