{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T04:11:07Z","timestamp":1776399067269,"version":"3.51.2"},"reference-count":59,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T00:00:00Z","timestamp":1747180800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["23-15-00060"],"award-info":[{"award-number":["23-15-00060"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>This study applies multivariate data analysis to deconvolute the spectral profiles of the Amide III region in the infrared spectra of gingival crevicular fluid (GCF). This reveals the impact of major oral diseases, such as dental caries and periodontal diseases, on the transformation of the secondary structure of GCF proteins. A two-stage analytical approach was employed: first, principal component analysis (PCA) was performed to establish the main factors of variation in the data, followed by pairwise comparisons of the samples based on the results of the Amide III profile deconvolution. The analysis also accounted for comorbidities, such as oncological and gastrointestinal diseases. This approach allowed for the identification of subtle differences in the composition and conformation of the secondary structure of GCF proteins while accounting for the superposition of multiple influencing factors. This methodology was effective in identifying biomarkers of oral diseases in GCF. For the first time, it has been demonstrated that the relative content of the \u03b2-sheet-associated component in the spectral profile of the secondary structure element of the protein fraction of GCF serves as a statistically significant marker for dental caries, regardless of the presence or absence of other diseases. Additionally, a significant decrease in the relative content of \u03b1-helix structures was observed in GCF from patients with oncological diseases. The changes in the spectral profile of the Amide III band of GCF identified in this study have not been previously detected using molecular spectroscopy, correlated with the secondary structure of proteins, or analyzed using multivariate analysis methods.<\/jats:p>","DOI":"10.3390\/ijms26104693","type":"journal-article","created":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T10:27:41Z","timestamp":1747218461000},"page":"4693","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Multivariate Spectroscopic Analysis of Protein Secondary Structures in Gingival Crevicular Fluid: Insights from FTIR Amide III Band Across Oral Disease Stages"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6724-0063","authenticated-orcid":false,"given":"Pavel","family":"Seredin","sequence":"first","affiliation":[{"name":"Department of Solid-State Physics and Nanostructures, Voronezh State University, 394018 Voronezh, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6019-3700","authenticated-orcid":false,"given":"Tatiana","family":"Litvinova","sequence":"additional","affiliation":[{"name":"Department of Solid-State Physics and Nanostructures, Voronezh State University, 394018 Voronezh, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuri","family":"Ippolitov","sequence":"additional","affiliation":[{"name":"Department of Solid-State Physics and Nanostructures, Voronezh State University, 394018 Voronezh, Russia"},{"name":"Department of Pediatric Dentistry with Orthodontia, Voronezh State Medical University, 394006 Voronezh, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1400-2870","authenticated-orcid":false,"given":"Dmitry","family":"Goloshchapov","sequence":"additional","affiliation":[{"name":"Department of Solid-State Physics and Nanostructures, Voronezh State University, 394018 Voronezh, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0939-0466","authenticated-orcid":false,"given":"Yaroslav","family":"Peshkov","sequence":"additional","affiliation":[{"name":"Department of Solid-State Physics and Nanostructures, Voronezh State University, 394018 Voronezh, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Boknam","family":"Chae","sequence":"additional","affiliation":[{"name":"Pohang Accelerator Laboratory, Beamline Research Division, Pohang 37673, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3285-5447","authenticated-orcid":false,"given":"Raul O.","family":"Freitas","sequence":"additional","affiliation":[{"name":"Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francisco C. B.","family":"Maia","sequence":"additional","affiliation":[{"name":"Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Cuevas-Gonz\u00e1lez, M.V., Cuevas-Gonz\u00e1lez, J.C., Espinosa-Crist\u00f3bal, L.F., Tovar-Carrillo, K.L., Saucedo-Acu\u00f1a, R.A., Garc\u00eda-Calder\u00f3n, A.G., Reyes-L\u00f3pez, S.Y., and Zambrano-Galv\u00e1n, G. (2024). The Potential of Gingival Crevicular Fluid as a Tool for Molecular Diagnosis: A Systematic Review. BioMed Res. Int., 2024.","DOI":"10.1155\/2024\/5560866"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1111\/prd.12595","article-title":"Utility of Gingival Crevicular Fluid Components for Periodontal Diagnosis","volume":"95","author":"Buduneli","year":"2024","journal-title":"Periodontology 2000"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1038\/s41368-024-00306-y","article-title":"A Multi-Platform Analysis of Human Gingival Crevicular Fluid Reveals Ferroptosis as a Relevant Regulated Cell Death Mechanism during the Clinical Progression of Periodontitis","volume":"16","author":"Torres","year":"2024","journal-title":"Int. J. Oral. Sci."},{"key":"ref_4","unstructured":"Lilge, L.D., and Huang, Z. (2023). An Investigation on the Amide I Band in Vibrational Spectra of Gingival Crevicular Fluid during Orthodontic Treatments. Translational Biophotonics: Diagnostics and Therapeutics III, SPIE."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Papagerakis, P. (2019). Saliva and Gingival Crevicular Fluid (GCF) Collection for Biomarker Screening. Odontogenesis: Methods and Protocols, Springer.","DOI":"10.1007\/978-1-4939-9012-2_41"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Bianchi, S., Bernardi, S., Simeone, D., Torge, D., Macchiarelli, G., and Marchetti, E. (2022). Proliferation and Morphological Assessment of Human Periodontal Ligament Fibroblast towards Bovine Pericardium Membranes: An In Vitro Study. Materials, 15.","DOI":"10.3390\/ma15238284"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"6483","DOI":"10.1007\/s00784-023-05253-2","article-title":"The Co-Occurrence of the Two Main Oral Diseases: Periodontitis and Dental Caries","volume":"27","author":"Baima","year":"2023","journal-title":"Clin. Oral Investig."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Yu, L.X., Wang, X., Feng, X.P., Tai, B.J., Hu, D.Y., Wang, B., Wang, C.X., Zheng, S.G., Liu, X.N., and Rong, W.S. (2021). The Relationship between Different Types of Caries and Periodontal Disease Severity in Middle-Aged and Elderly People: Findings from the 4th National Oral Health Survey of China. BMC Oral Health, 21.","DOI":"10.1186\/s12903-021-01585-1"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"20230118","DOI":"10.1002\/VIW.20230118","article-title":"Succession of the Oral Microbiome with the Increasing Severity of Periodontitis","volume":"5","author":"Mi","year":"2024","journal-title":"VIEW"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Chen, W., Jiang, Q., Yan, G., and Yang, D. (2020). The Oral Microbiome and Salivary Proteins Influence Caries in Children Aged 6 to 8 Years. BMC Oral Health, 20.","DOI":"10.1186\/s12903-020-01262-9"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Fadli, N.A., Abdul Rahman, M., Karsani, S.A., and Ramli, R. (2024). Oral and Gingival Crevicular Fluid Biomarkers for Jawbone Turnover Diseases: A Scoping Review. Diagnostics, 14.","DOI":"10.3390\/diagnostics14192184"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Khurshid, Z., Mali, M., Naseem, M., Najeeb, S., and Zafar, M.S. (2017). Human Gingival Crevicular Fluids (GCF) Proteomics: An Overview. Dent. J., 5.","DOI":"10.3390\/dj5010012"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"852","DOI":"10.1111\/jcpe.13964","article-title":"LIGHT Protein: A Novel Gingival Crevicular Fluid Biomarker Associated with Increased Probing Depth after Periodontal Surgery","volume":"51","author":"Esberg","year":"2024","journal-title":"J. Clin. Periodontol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Seredin, P., Litvinova, T., Ippolitov, Y., Goloshchapov, D., Peshkov, Y., Kashkarov, V., Ippolitov, I., and Chae, B. (2024). A Study of the Association between Primary Oral Pathologies (Dental Caries and Periodontal Diseases) Using Synchrotron Molecular FTIR Spectroscopy in View of the Patient\u2019s Personalized Clinical Picture (Demographics and Anamnesis). Int. J. Mol. Sci., 25.","DOI":"10.3390\/ijms25126395"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Lepore, M., Portaccio, M., d\u2019Apuzzo, F., Nucci, L., Grassia, V., Annunziata, M., and Camerlingo, C. (2024, January 23\u201325). Rapid Acquisition of Gingival Crevicular Fluid FT-IR Spectra for Monitoring Orthodontic Treatments. Proceedings of the 2024 IEEE Sensors Applications Symposium (SAS), Naples, Italy.","DOI":"10.1109\/SAS60918.2024.10636387"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Santiago-G\u00f3mez, I., Carrera-Lanestosa, A., Gonz\u00e1lez-Alejo, F.A., Guerra-Que, Z., Garc\u00eda-Alamilla, R., Rivera-Armenta, J.L., and Garc\u00eda-Alamilla, P. (2025). Pectin Extraction Process from Cocoa Pod Husk (Theobroma cacao L.) and Characterization by Fourier Transform Infrared Spectroscopy. ChemEngineering, 9.","DOI":"10.3390\/chemengineering9020025"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1107\/S0909049513019444","article-title":"Local Study of Fissure Caries by Fourier Transform Infrared Microscopy and X-Ray Diffraction Using Synchrotron Radiation","volume":"20","author":"Seredin","year":"2013","journal-title":"J. Synchrotron Radiat."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1016\/j.molstruc.2018.09.013","article-title":"Infrared Microspectroscopy Characterization of Gingival Crevicular Fluid during Orthodontic Treatment","volume":"1176","author":"Portaccio","year":"2019","journal-title":"J. Mol. Struct."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1561","DOI":"10.1021\/acs.analchem.0c03943","article-title":"Searching for a Better Match between Protein Secondary Structure Definitions and Protein FTIR Spectra","volume":"93","author":"Goormaghtigh","year":"2021","journal-title":"Anal. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Seredin, P., Goloshchapov, D., Kashkarov, V., Lukin, A., Peshkov, Y., Ippolitov, I., Ippolitov, Y., Litvinova, T., Vongsvivut, J., and Chae, B. (2023). Changes in Dental Biofilm Proteins\u2019 Secondary Structure in Groups of People with Different Cariogenic Situations in the Oral Cavity and Using Medications by Means of Synchrotron FTIR-Microspectroscopy. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms242015324"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/S0301-4622(99)00060-5","article-title":"Identification of Beta-Turn and Random Coil Amide III Infrared Bands for Secondary Structure Estimation of Proteins","volume":"80","author":"Cai","year":"1999","journal-title":"Biophys. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2145","DOI":"10.1038\/s41467-018-04319-0","article-title":"Protein Disorder\u2013Order Interplay to Guide the Growth of Hierarchical Mineralized Structures","volume":"9","author":"Elsharkawy","year":"2018","journal-title":"Nat. Commun."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1206","DOI":"10.1021\/ja411081t","article-title":"Accurate Determination of Interfacial Protein Secondary Structure by Combining Interfacial-Sensitive Amide I and Amide III Spectral Signals","volume":"136","author":"Ye","year":"2014","journal-title":"J. Am. Chem. Soc."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"To\u0142pa, B., Paja, W., Jakubczyk, P., \u0141ach, K., Trojnar, E., Gala-B\u0142\u0105dzi\u0144ska, A., Kowal, A., Kl\u0119bowski, B., Cebulski, J., and Depciuch, J. (2025). Differentiation of Glioblastoma G4 and Two Types of Meningiomas Using FTIR Spectra and Machine Learning. Anal. Biochem., 699.","DOI":"10.1016\/j.ab.2024.115754"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Mishra, A., Zehra, S., Bharti, P.K., Mathur, S.R., Ranjan, P., Batra, A., Inampudi, K.K., Modi, G.P., Nikolajeff, F., and Kumar, S. (2024). Spectroscopic Insight into Breast Cancer: Profiling Small Extracellular Vesicles Lipids via Infrared Spectroscopy for Diagnostic Precision. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-59863-1"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"962","DOI":"10.1177\/00037028241255150","article-title":"Differentiating Nylon Samples with Visually Indistinguishable Fluorescence Using Principal Component Analysis and Common Dimension Partial Least Squares Linear Discriminant Analysis with Synchronous Fluorescence Spectroscopy","volume":"78","author":"Froelich","year":"2024","journal-title":"Appl. Spectrosc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1007\/s12161-024-02626-5","article-title":"Identification of Adulterated Cooking Oil by Raman Spectroscopy","volume":"17","author":"Shehnaz","year":"2024","journal-title":"Food Anal. Methods"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"779","DOI":"10.18280\/ijdne.190308","article-title":"Distinguishing Weed Species Using Near Infrared Reflectance Spectroscopy and Principal Component Analysis","volume":"19","author":"Hasanuddin","year":"2024","journal-title":"IJDNE"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"109688","DOI":"10.1016\/j.foodhyd.2023.109688","article-title":"A Determination of the Composition and Structure of the Polysaccharides Fractions Isolated from Apple Cell Wall Based on FT-IR and FT-Raman Spectra Supported by PCA Analysis","volume":"150","author":"Zdunek","year":"2024","journal-title":"Food Hydrocoll."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1080\/10739149.2022.2158857","article-title":"Characterization of the Degradation of Dipyrone (Metamizole) in Expired Oral Pharmaceutical Products by Raman Spectroscopy and Principal Component Analysis (PCA)","volume":"51","author":"Nita","year":"2023","journal-title":"Instrum. Sci. Technol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3390\/clockssleep6010001","article-title":"Primer on Reproducible Research in R: Enhancing Transparency and Scientific Rigor","volume":"6","author":"Siraji","year":"2023","journal-title":"Clocks Sleep"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1207\/s15327906mbr0102_10","article-title":"The Scree Test For The Number Of Factors","volume":"1","author":"Cattell","year":"1966","journal-title":"Multivar. Behav. Res."},{"key":"ref_33","unstructured":"Kutner, M.H. (2005). Applied Linear Statistical Models, McGraw-Hill Irwin. [5th ed.]. The McGraw-Hill\/Irwin Series Operations and Decision Sciences."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Seredin, P., Goloshchapov, D., Kashkarov, V., Nesterov, D., Ippolitov, Y., Ippolitov, I., and Vongsvivut, J. (2022). Effect of Exo\/Endogenous Prophylaxis Dentifrice\/Drug and Cariogenic Conditions of Patient on Molecular Property of Dental Biofilm: Synchrotron FTIR Spectroscopic Study. Pharmaceutics, 14.","DOI":"10.3390\/pharmaceutics14071355"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"e10","DOI":"10.1016\/j.forsciint.2015.04.020","article-title":"The Detection and Discrimination of Human Body Fluids Using ATR FT-IR Spectroscopy","volume":"252","author":"Orphanou","year":"2015","journal-title":"Forensic Sci. Int."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"536","DOI":"10.1177\/0003702819885958","article-title":"Age and Gender Characteristics of the Infrared Spectra of Normal Human Saliva","volume":"74","author":"Sarf","year":"2020","journal-title":"Appl. Spectrosc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"801","DOI":"10.3233\/JAD-151163","article-title":"FTIR and Raman Spectroscopy Applied to Dementia Diagnosis Through Analysis of Biological Fluids","volume":"52","author":"Lopes","year":"2016","journal-title":"J. Alzheimer\u2019s Dis."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Camerlingo, C., Portaccio, M., d\u2019Apuzzo, F., Nucci, L., Perillo, L., and Lepore, M. (2022). \u03bc-FTIR, \u03bc-Raman, and SERS Analysis of Amide I Spectral Region in Oral Biofluid Samples during Orthodontic Treatment. Sensors, 22.","DOI":"10.3390\/s22207874"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"d\u2019Apuzzo, F., Nucci, L., Delfino, I., Portaccio, M., Minervini, G., Isola, G., Serino, I., Camerlingo, C., and Lepore, M. (2021). Application of Vibrational Spectroscopies in the Qualitative Analysis of Gingival Crevicular Fluid and Periodontal Ligament during Orthodontic Tooth Movement. J. Clin. Med., 10.","DOI":"10.3390\/jcm10071405"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Carrasquillo, K.G., Sanchez, C., and Griebenow, K. (2000). Relationship between Conformational Stability and Lyophilization-Induced Structural Changes in Chymotrypsin. Biotechnol. Appl. Biochem., 31.","DOI":"10.1042\/BA19990087"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Stani, C., Vaccari, L., Mitri, E., and Birarda, G. (2020). FTIR Investigation of the Secondary Structure of Type I Collagen: New Insight into the Amide III Band. Spectrochim. Acta Part. A Mol. Biomol. Spectrosc., 229.","DOI":"10.1016\/j.saa.2019.118006"},{"key":"ref_42","unstructured":"Nafie, L.A., and Mantsch, H.H. (1993). Fourier Transform Infrared Analysis of Amide III Bands of Proteins for the Secondary Structure Estimation. Biomolecular Spectroscopy III, SPIE."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3344","DOI":"10.1021\/bm2006032","article-title":"Synchrotron FTIR Microspectroscopy of Single Natural Silk Fibers","volume":"12","author":"Ling","year":"2011","journal-title":"Biomacromolecules"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Ricciardi, V., Portaccio, M., Perna, G., Lasalvia, M., Capozzi, V., Cammarata, F.P., Pisciotta, P., Petringa, G., Delfino, I., and Manti, L. (2021). FT-IR Transflection Micro-Spectroscopy Study on Normal Human Breast Cells after Exposure to a Proton Beam. Appl. Sci., 11.","DOI":"10.3390\/app11020540"},{"key":"ref_45","first-page":"1","article-title":"Secondary Structure of Proteins in the Amorphous Dehydrated State Probed by FTIR Spectroscopy. Dehydration-Induced Structural Changes and Their Prevention","volume":"3","author":"Griebenow","year":"1999","journal-title":"Internet J. Vib. Spectrosc."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1093\/ibd\/izac241","article-title":"The Oral-Gut Axis: Periodontal Diseases and Gastrointestinal Disorders","volume":"29","author":"Lam","year":"2023","journal-title":"Inflamm. Bowel Dis."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1038\/s41577-020-00488-6","article-title":"Local and Systemic Mechanisms Linking Periodontal Disease and Inflammatory Comorbidities","volume":"21","author":"Hajishengallis","year":"2021","journal-title":"Nat. Rev. Immunol."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Ghimire, H., Garlapati, C., Janssen, E.A.M., Krishnamurti, U., Qin, G., Aneja, R., and Perera, A.G.U. (2020). Protein Conformational Changes in Breast Cancer Sera Using Infrared Spectroscopic Analysis. Cancers, 12.","DOI":"10.3390\/cancers12071708"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.molstruc.2013.05.005","article-title":"Comparison of Hair from Rectum Cancer Patients and from Healthy Persons by Raman Microspectroscopy and Imaging","volume":"1048","author":"Wei","year":"2013","journal-title":"J. Mol. Struct."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"4050","DOI":"10.1364\/BOE.10.004050","article-title":"Spectroscopic Signature of the Pathological Processes of Carious Dentine Based on FTIR Investigations of the Oral Biological Fluids","volume":"10","author":"Seredin","year":"2019","journal-title":"Biomed. Opt. Express"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"255","DOI":"10.17219\/dmp\/150888","article-title":"The mRNA Expression of Genes Encoding Selected Antioxidant Enzymes and Thioredoxin, and the Concentrations of Their Protein Products in Gingival Crevicular Fluid and Saliva during Periodontitis","volume":"60","author":"Toczewska","year":"2023","journal-title":"Dent. Med. Probl."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"103058","DOI":"10.1016\/j.vibspec.2020.103058","article-title":"Comparative Analysis of Dentine and Gingival Fluid Molecular Composition and Protein Conformations during Development of Dentine Caries: A Pilot Study","volume":"108","author":"Seredin","year":"2020","journal-title":"Vib. Spectrosc."},{"key":"ref_53","unstructured":"Bergmeier, L.A. (2018). Saliva and Gingival Crevicular Fluid: Contributions to Mucosal Defense. Oral Mucosa in Health and Disease: A Concise Handbook, Springer International Publishing."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Husson, F., L\u00ea, S., and Pag\u00e8s, J. (2017). Exploratory Multivariate Analysis by Example Using R, CRC Press Taylor & Francis Group. [2nd ed.].","DOI":"10.1201\/b21874"},{"key":"ref_55","unstructured":"(2024, April 11). FactoMineR: Catdes. Available online: http:\/\/factominer.free.fr\/factomethods\/categories-description.html."},{"key":"ref_56","unstructured":"Kassambara, A., and Mundt, F. (2025, May 11). Factoextra: Extract and Visualize the Results of Multivariate Data Analyses. Available online: https:\/\/kassambara.r-universe.dev\/factoextra\/factoextra.pdf."},{"key":"ref_57","unstructured":"Arnholt, A., and Evans, B. (2025, May 11). BSDA: Basic Statistics and Data Analysis. Available online: https:\/\/cran.r-project.org\/web\/packages\/BSDA\/BSDA.pdf."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"353","DOI":"10.4097\/kja.d.18.00242","article-title":"What Is the Proper Way to Apply the Multiple Comparison Test?","volume":"71","author":"Lee","year":"2018","journal-title":"Korean J. Anesthesiol."},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Wickham, H. (2016). Ggplot2: Elegant Graphics for Data Analysis, Springer International Publishing. [2nd ed.]. Use R!.","DOI":"10.1007\/978-3-319-24277-4_9"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/10\/4693\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:32:31Z","timestamp":1760031151000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/10\/4693"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,14]]},"references-count":59,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025,5]]}},"alternative-id":["ijms26104693"],"URL":"https:\/\/doi.org\/10.3390\/ijms26104693","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,14]]}}}