A multiplex immunoassay demonstrates reductions in gingival crevicular fluid cytokines following initial periodontal therapy

Thunell DH, Tymkiw KD, Johnson GK, Joly S, Burnell KK, Cavanaugh JE, Brogden KA, Guthmiller JM. A multiplex immunoassay demonstrates reductions in gingival crevicular fluid cytokines following initial periodontal therapy. J Periodont Res 2009; doi: 10.1111/j.1600‐0765.2009.01204.x. © 2009 John Wiley & Sons A/S Background and Objective: Cytokines and chemokines play an important role in the pathogenesis of periodontal diseases. The objective of this study was to quantitatively assess the effect of initial periodontal therapy on gingival crevicular fluid levels of a comprehensive panel of cytokines and chemokines, including several less extensively studied mediators. Material and Methods: Clinical examinations were performed and gingival crevicular fluid samples obtained from six subjects with generalized severe chronic periodontitis prior to initial periodontal therapy and at re‐evaluation (6–8 weeks). Four diseased and two healthy sites were sampled in each subject. Twenty‐two gingival crevicular fluid mediators were examined using a multiplex antibody capture and detection platform. Statistical analyses were performed by fitting mixed effects linear models to log‐transformed gingival crevicular fluid values. Results: Gingival crevicular fluid interleukin (IL)‐1α and IL‐1β were the only cytokines to differ in initially diseased vs. initially healthy sites. Following initial therapy, 13 of the 16 detectable cytokines and chemokines decreased significantly in diseased sites, including IL‐1α, IL‐1β, IL‐2, IL‐3, IL‐6, IL‐7, IL‐8, IL‐12 (p40), CCL5/regulated on activation, normally T cell expressed and secreted (RANTES), eotaxin, macrophage chemotactic protein‐1, macrophage inflammatory protein‐1α and interferon‐γ. At healthy sites, only three of the 16 mediators were significantly altered following therapy. Conclusion: This is the first study, to our knowledge, to evaluate such an extensive panel of gingival crevicular fluid mediators within the same sample prior to and following initial therapy. The results confirm that periodontal therapy effectively reduces pro‐inflammatory cytokines and chemokines, including less well‐described mediators that may be important in initiation and progression of periodontitis. The multiplex assay will prove useful for future gingival crevicular fluid studies.     

Interleukin-8 and β-glucuronidase in gingival crevicular fluid

Abstract Polymorphonuclear leukocytes (PMN) play a critical role in the host's response to the subgingival microflora. Interleukin-8 (IL-8) is a potent chemotactic and activating factor for PMN. In this study, the presence of IL-8 in gingival crevicular fluid (GCF) was examined in relation to the PMN indicator β-glucuronidase (βG), as well as clinical parameters of chronic inflammatory periodontal disease. Data was obtained from 30 patients with periodontitis and 14 healthy controls. For the control group, GCF and clinical data were obtained only once. For the periodontitis patients, clinical data and GCF samples were collected prior to treatment, and GCF samples were again collected 2 weeks after scaling and root planing. Comparing control and periodontitis patients prior to treatment, IL-8 concentration was lower in the patients with periodontitis. Scaling and root planing resulted in either an increase or a decrease in total IL-8 and IL-8 concentration GCF. A reduction in total IL-8 or IL–8 concentration was accompanied by a corresponding reduction in βG activity. An increase in total IL-8 or IL-8 concentration after scaling and root planing was associated with an increase in βG activity in some patients and a reduction in βG activity in other patients. The periodontitis patients who did not demonstrate a linkage between IL-8 and βG activity in GCF were those individuals with the highest βG activity prior to treatment. As elevated βG activity in GCF has been associated with an increased risk for probing attachment loss, the absence of a direct relationship between IL-8 in GCF and PMN recruitment into the gingival crevice may characterize individuals at risk for progression of periodontitis.     

The effect of restorative materials on cytokines in gingival crevicular fluid

ObjectiveComposition of the restorative materials may cause inflammatory responses by monocyte activation and changes in the levels of cytokine released from different cells. Interleukin-6 (IL-6), interleukin-8 (IL-8) and Tumor necrosis factor alpha (TNF-α) are important cytokine for evaluating of the inflammatory process. The aim of this study was to evaluate the different restorative materials used in class V cavities effect on gingival crevicular fluid inflammatory cytokine levels.Design60 individuals having Class V carious cavities participated in the study. Cavities were restored with FiltekZ250, DyractXP, Fuji IX, Cavex avalloy restorative materials. Changes in clinical and biochemical parameters were evaluated before restorations, seven and 21 days after restorations. Contralateral tooth intact enamel surface was determined as control side. Periotron8000 device was used for detection of GCF volume. Cytokine level of GCF was evaluated by Human ELISA kits. Data were analyzed using Mann-Whitney U test and Wilcoxon signed ranks test. The correlations between clinical parameters and biochemical parameters were examined by Spearman's rank correlation analysis.ResultsAfter restorative treatments PI and GI scores were decreased compared with baseline evaluations. There was a significant difference in GCF levels between experimental and control sites in all groups. GCF IL-6 levels in all groups except Filtek Z250, GCF IL-8 levels in all groups except Fuji IX, GCF TNF-α level in only Fuji IX showed significant differences between experimental and control sites.ConclusionsThe obtained data supported that all of the tested materials caused changes in GCF cytokine levels.     

T-helper-related cytokines in gingival crevicular fluid from adolescents with Down syndrome

Subjects with Down syndrome have a high prevalence of periodontal disease. The aim was to investigate the level of Th1-, Th2- and Th17-related cytokines in the gingival crevicular fluid (GCF) of subjects with Down syndrome. Subjects with Down syndrome (n = 24) and controls (n = 29) with a mean age of 16.4 years were clinically examined with respect to periodontal probing depth (PD) and gingival inflammation in terms of bleeding on probing (BOP%). The controls were matched to subjects with Down syndrome regarding age and gingival inflammation (BOP%). All subjects answered a questionnaire regarding oral hygiene, medical history and socioeconomic background. GCF was collected and the concentration of the cytokines, IFN-γ, TNF-α, IL-1β, IL-4, IL-6, IL-10, IL-12 and IL-17 were determined using Bio-Plex cytokine multiplex assays. The volume of GCF (microliters) was significantly higher in subjects with Down syndrome (P < 0.001) compared with controls. The mean concentrations (picogrammes per millilitre) of IL-1β (P < 0.001), IL-4 (P = 0.002), IL-6 (P = 0.005), IL-10 (P = 0.001), IL-12 (P = 0.003), IFN-γ (P = 0.002), and TNF-α (P = 0.002) in GCF, respectively, were significantly higher in subjects with Down syndrome compared with controls. The regression line of the relationship between IFN-γ and IL-4 in GCF differed significantly (P = 0.006) in subjects with Down syndrome compared to controls. Subjects with Down syndrome demonstrated higher concentration of Th1-, Th2- and Th17-related cytokines with an altered relationship between Th1 cytokine, IFN-γ and Th2 cytokine, IL-4, in volume GCF compared to controls.     

The subgingival microflora and gingival crevicular fluid cytokines in refractory periodontitis

Abstract Refractory periodontitis manifests as a rapid, unrelenting, progressive loss of attachment despite the type and frequency of therapy. This study examined possible relationships between cytokine levels in gingival crevicular fluid (GCF), occurrence of specific periodontopathic microflora. and disease activity in patients with refractory periodontitis. Refractory periodontitis patients (7 male and 3 female) were selected on the basis of history and longitudinal clinical observations. In each patient. 2 teeth with pocket depths greater than 6 mm were selected and individual acrylic stents were fabricated with reference grooves for each site. The sites were examined at both baseline and 3 months later. The pattern and amount of alveolar bone resorption were assayed by quantitative digital subtraction radiography. Pocket depth and attachment loss were measured with a Florida Probe. The gingival index was measured at 4 sites around each sample tooth. Sites were divided into active sites (2.1 mm loss of attachment in 3 months) or inactive sites (2.0 mm loss of attachment in 3 months). The distribution and prevalence of the predominant microflora in active and inactive sites were compared using anaerobic culture and indirect immunofluorescence. Interleukin-1β, 2, 4, 6 and tumor necrosis factor-α (TNF-α) levels in gingival crevicular fluid (GCF) were quantified by ELISA. Prevotella intermedia and Eikenella corrodens significantly decreased in inactive sites but remained the same in active sites after 3 months. The active sites revealed significantly higher GCF levels of IL-2 and IL-6 than inactive sites at both baseline and at 3 months. IL-1β was also significantly greater in active sites than in inactive sites at 3 months. Alveolar bone loss in active sites correlated with increased GCF levels of IL-1β and 1L-β. These results suggest that GCF levels of IL-1β, IL-2 and IL-6 and P. intermedia and E. corrodens in subgingival plaque may serve as possible indicators of disease activity in refractory periodontitis.     

人健康牙周组织龈沟液中细胞因子表达水平的初步研究

目的初步探讨人健康牙周组织龈沟液中细胞因子的普遍水平,为确立诊断指标及后续研究提供正常标准范围参考。方法选择牙周组织健康者每人4～8颗后牙(第二前磨牙及第二磨牙),检查相关临床指标,测定龈沟液分泌量,并通过微量龈沟液炎症标志物组合的Luminex液相芯片多因子检测体系测定19种细胞因子表达水平,包括3种集落细胞刺激因子、7种白细胞介素、6种趋化性细胞因子、血管内皮细胞生长因子、肿瘤坏死因子-α以及干扰素-γ。结果检测到人健康牙周组织中209颗后牙(第二前磨牙103颗、第二磨牙106颗)龈沟液分泌量及所含19种细胞因子表达水平。结论初步确定人健康牙周组织龈沟液中与骨代谢密切相关的19种细胞因子的大致标准范围。     

Profiling the cytokines in gingival crevicular fluid using a cytokine antibody array

BACKGROUND: Various compounds have been detected in gingival crevicular fluid (GCF) as indicators of periodontal disease activity. Therefore, the analysis of GCF may be especially beneficial for diagnosing current periodontal status and addressing the effects of treatment. Moreover, the identification of new markers in GCF may also contribute to elucidating novel mechanisms involved in periodontal disease. This study sought novel marker proteins specific to chronic periodontitis by profiling cytokines in GCF using a cytokine antibody array system. METHODS: Human cytokine array V, which detects 79 cytokines on one membrane, was used to determine the profile of cytokines in GCF from seven subjects with chronic periodontitis and seven subjects with healthy periodontia. The profile was exposed to x-ray film and quantified using image analysis software. Healthy and diseased sites were compared statistically. RESULTS: We detected 10 cytokines in periodontally healthy sites and 36 cytokines in periodontally diseased sites. Interleukin-8 (IL-8) and transforming growth factor-beta 2 (TGF-beta2) were detected at high levels in healthy and diseased subjects. There were significant differences between healthy and diseased subjects in the levels of tissue inhibitor of metalloproteinases-2 (TIMP-2), tumor necrosis factor-beta (TNF-beta), growth-related oncogene (GRO), interferon-inducible protein-10 (IP-10), angiogenin (Ang), vascular endothelial growth factor (VEGF), insulin-like growth factor binding protein-3 (IGFBP-3), osteoprotegerin (OPG), epidermal growth factor (EGF), glial-derived neurotrophic factor (GDNF), pulmonary and activation-regulated chemokine (PARC), oncostatin M (OSM), fibroblast growth factor-4 (FGF-4), IL-16, homologous to lymphotoxins (LIGHT), and placenta growth factor (PlGF). Of these, the newly detected cytokines were GRO, Ang, IGFBP-3, GDNF, PARC, OSM, FGF-4, IL-16, LIGHT, and PlGF. CONCLUSIONS: In this study, we detected several cytokines in GCF using a cytokine antibody array system, including both inflammatory cytokines and various growth factors. Therefore, periodontal disease may participate in the wound healing process and in tissue destruction via the inflammatory process. Our results suggest that the quantification of these cytokines in GCF provides useful information for the diagnosis of periodontal disease status.     

Alterations in crevicular fluid flow during healing following gingival surgery

The relationship between gingival crevicular fluid flow and healing after gingival surgery, as assessed by biopsy, cytologic and microbial smears, was evaluated. Eighty-five periodontal pockets from the maxillary anterior and premolar teeth were studied in nine patients. Gingival fluid flow measurements, cytologic and microbial smears were taken weekly from each periodontal pocket for five weeks. The gingivectomy was performed at the first week and the tissue biopsied. Additional biopsies were also taken of selected areas on the fifth week. The results were analyzed to ascertain any correlation between gingival crevicular fluid flow and gingival inflammation during healing. The following conclusions can be drawn:

• 1 Quantity of gingival crevicular fluid, sulcular cytologic and microbial smears can be of value in assessing gingival status.
• 2 A direct relationship exists between the rate of crevicular fluid flow and healing following gingival surgery.
• 3 A healthy crevicular epithelium lining the gingival sulcus appears to function as a barrier, thereby retaining the gingival tissue fluid.

     

龈沟液中与牙周病有关的细胞因子的研究进展

牙周病时龈沟液内含有多种可作为诊断指标的细胞因子,由于取样简单无创,且能重复取样,易为患者所接受。因此,近年来学者们对龈沟液内的细胞因子在牙周炎活动期的诊断﹑治疗及疗效评价中作用的研究很多。本文对龈沟液中与牙周病有关的细胞因子的研究进展作一综述。     

Physical activity, inflammatory biomarkers in gingival crevicular fluid and periodontitis

Aims: To examine the associations of physical activity with interleukin 1- β (IL-1 β ), C-reactive protein (CRP) and periodontitis and to investigate whether any relationship between physical activity and inflammatory mediators differs between periodontitis cases and non-cases.
Material and Methods: In this population-based case control study of Australians aged 18+ years, dentists conducted oral epidemiologic examinations identifying cases with moderate or severe periodontitis and periodontally healthy controls. Gingival crevicular fluid samples collected during examinations were analysed for inflammatory biomarkers. Subject-completed questionnaires assessed leisure-time physical activity. Exposure odds ratios (ORs) were estimated in multivariable logistic regression models adjusting for periodontitis risk indicators.
Results: Of 751 subjects (359 cases, 392 controls), those meeting a prescribed threshold for leisure-time physical activity had lower adjusted odds of elevated IL-1 β : OR=0.69, (95% CI=0.50–0.94) and detectable CRP: OR=0.70 (0.50–0.98) than less active adults. Physical activity was not associated with periodontitis: OR=1.14 (0.80–1.62). Periodontitis modified the association between levels of physical activity and detectable CRP. Increasing quartiles of physically activity were associated with decreasing probability of detectable CRP, but the effect was limited to periodontitis cases and was not apparent among non-cases.
Conclusion: Leisure-time physical activity may protect against an excessive inflammatory response in periodontitis.     

实验性种植体周围炎龈沟液炎症细胞因子浓度的检测分析

目的　研究狗的实验性种植体周围炎龈沟液 (GCF)IL 1α、IL 6、TNF α等几种炎性细胞因子浓度的变化与骨吸收的关系。方法　建立狗的种植体周围炎的动物模型 ,对龈沟液的IL 1α、IL 6、TNF α等细胞因子进行ELISA法检测 ,并对种植体进行X线及大体观察。结果　 4 - 0线结扎 4周时龈沟液细胞因子的浓度明显增高 ,骨性界面的骨组织出现明显吸收 ,而结扎 4周后去除结扎线继续观察组与继续结扎组两组之间无显著的差异 ,但与结扎 4周时相比有显著变化。结论　发生种植体周围炎时与天然牙牙周炎相似 ,IL 1α、IL 6、TNF α等炎症细胞因子参与炎症过程 ,与界面骨破坏有关     

Granulocyte elastase activity in static and flow gingival crevicular fluid

OBJECTIVES: This study aimed to evaluate the volume of gingival crevicular fluid (GCF) and granulocyte elastase activity in static GCF (sGCF) and flow GCF (fGCF) from subjects with various periodontal conditions. METHODS: Eleven periodontally healthy, 10 gingivitis and 12 periodontitis subjects were recruited and the sites investigated consisted of healthy sites from healthy subjects (HH); healthy (HG) and gingivitis sites (GG) from gingivitis subjects; and healthy (HP), gingivitis (GP) and periodontitis sites (PP) from periodontitis subjects. fGCF samples were collected either 1 min or 5 min following sGCF collection by paper strip technique. GCF volume was determined by Periotron 6000 and granulocyte elastase activity was assayed with a specific substrate [l-pyroglutamyl-l-prolyl-l-valine-p-nitroanilide(pGluProVal-pNA)]. RESULTS: At baseline, no significant differences existed in clinical and GCF parameters between the two matched sites for subsequent collection of fGCF samples either 1 min or 5 min after sGCF sampling in all subjects. The flow exudate in HG and HP sites quickly replenished to sGCF levels, while a delayed replenishment was found in HH sites, despite the similar sGCF volumes of these sites. The GCF volume and elastase levels in the fGCF at 1 min were higher in GP sites than in GG sites (P < 0.05). Overall, depletion of elastase levels in the fGCF at 1 min was observed in all subjects, whereas elastase levels in the fGCF at 5 min had replenished to sGCF levels in HP, GP, PP sites and GG sites, but had remained at a lower level in HH and HG sites. An overall positive correlation was found between sGCF and fGCF for GCF volume and elastase activity (P < 0.001); however, this correlation varied with GCF parameters and with site conditions of the subjects concerned. CONCLUSIONS: This study shows that patterns of dynamic changes in GCF flow and elastase activity varied under different periodontal conditions. Assessment of both sGCF and fGCF may allow better insight into the dynamic change of the target components in GCF.     

Analysis in gingival crevicular fluid of two oligopeptides derived from human hemoglobin β-chain

HPLC on a reversed phase column, amino acid sequencing and mass spectrometry were used to determine the structure of two human gingival crevicular exudate oligopeptides (Leu-Thr-Pro-Glu-Glu-Lys-Ser-Ala-Val-Thr-Ala-Leu and Leu-Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe) which were shown to have been derived from the β-chain of hemoglobin. These sequences may simply represent two degradation products of the β-chain. However, their preservation in an exudate characterized by active peptidolysis may also prompt the question about their possible more specific role.     

Expression of cytokines in the gingival crevicular fluid and serum from patients with inflammatory bowel disease and untreated chronic periodontitis

Figueredo CM, Brito F, Barros FC, Menegat JSB, Pedreira RR, Fischer RG, Gustafsson A. Expression of cytokines in the gingival crevicular fluid and serum from patients with inflammatory bowel disease and untreated chronic periodontitis. J Periodont Res 2011; 46: 141–146.© 2010 John Wiley & Sons A/S Background and Objective: Previous studies have reported an increased prevalence/severity of chronic periodontitis in patients with inflammatory bowel disease. However, the pathogenesis of periodontal lesions in such patients has not been characterized. The aim of this pilot study was to characterize the pattern of expression of cytokines in the gingival crevicular fluid and serum from patients with untreated chronic periodontitis and Crohn’s disease, ulcerative colitis and systemically healthy controls. Material and Methods: Fifteen patients with Crohn’s disease, 15 patients with ulcerative colitis and 15 controls participated in the study. All subjects had been diagnosed with untreated chronic periodontitis. The clinical parameters evaluated were clinical attachment loss, bleeding on probing and percentage of plaque. The gingival crevicular fluid was sampled from four shallow and four deep periodontal sites of each patient. The concentrations of the cytokines interleukin (IL)‐1β, IL‐4, IL‐6, IL‐10, IL‐12p40, IL‐12p70, interferon‐γ and tumor necrosis factor‐α were measured using a commercially available Lincoplex kit and the concentration of IL‐18 was measured using an ELISA. Results: Multiple comparisons analysis showed that clinical attachment loss, bleeding on probing, percentage of plaque and volume of gingival crevicular fluid were similar across the groups. The concentration of IL‐4 in the gingival crevicular fluid differed significantly between groups in shallow sites (p = 0.046), with higher values found for the controls. In serum, the concentration of IL‐18 was also significantly different between groups, with lower values found for controls (p = 0.018). Conclusion: This study showed a higher concentration of IL‐18 in serum, but not in the gingival crevicular fluid, from periodontitis patients with Crohn’s disease or ulcerative colitis compared with controls. The expression of cytokines was similar in the gingival crevicular fluid from patients with untreated chronic periodontitis who also had Crohn’s disease or ulcerative colitis and in systemically healthy controls with untreated chronic periodontitis.     

Effect of orthodontic force on expression levels of ten cytokines in gingival crevicular fluid

Various types of inflammatory mediators are involved in the cascade of biological events behind tissue remodeling allowing orthodontic tooth movement. This split-mouth longitudinal study aimed to evaluate the gingival crevicular fluid (GCF) levels of ten cytokines, IL-6, IL-8, IL-10, IL-13, IL-17, IFN-γ, GM-CSF, MCP-1, MIP-1β and TNF-α, during initial orthodontic treatment. The sample comprised 15 healthy patients (9 males and 6 females, 13.9 ± 2.5 years). The lower (test) incisors were moved using fixed appliance carrying a 0.014-inch nickel titanium wire, whereas the upper (control) incisors were bonded without any force. The GCF was collected from the test and control teeth before fixed appliance mounting (baseline) and after 1, 7 and 21 days. In 6 sites per tooth, from canine to canine, periodontal conditions were defined as the percentage of sites with visible plaque and bleeding on probing. The total GCF cytokines levels were quantified using multianalysis Luminex technology. Throughout the experimental term, and for both test and control teeth, the mean percentage of sites with visible plaque and bleeding on probing were generally below 25% and 15%, respectively, although variability was also seen. In the test teeth, the GCF levels of all the cytokines remained constant throughout the experimental term. On the contrary, significant reductions were seen in the control teeth for each cytokine. Moreover, significantly greater levels of IL-6, GM-CSF, MCP-1 and TNFα were seen in the test teeth as compared to the control teeth at 7 days. The reasons for the differential behavior in the levels of all the investigated cytokines between the test and control teeth may be related to the presence of orthodontic forces and/or subclinical tissue inflammation. Further investigation is needed to elucidate potential roles for these biomarkers in the tissue remodeling incident to orthodontic tooth movement.     

Antibody to collagen type I in gingival crevicular fluid

Gingival crevice fluid (GCF) was collected from inflamed sites in 20 patients before and 6 weeks after treatment. Levels of IgG to human collagen Type I were measured in the GCF and autologous serum using an enzyme-linked immunosorbent assay and compared with levels in control sera. IgG antibody to collagen was detected in GCF at significantly (P less than 0.01) higher levels than in control sera, but these levels were not significantly (P greater than 0.05) different from those in autologous sera. The levels of IgG antibody in GCF and autologous sera did not alter significantly (P greater than 0.05) after treatment. IgG antibody to collagen Type I is present in GCF in the diseased and healing state.     

模拟高原条件下大鼠龈沟液中TNF-α、PGE2、IL-8与牙周炎的相关性研究

目的:研究模拟高原条件下大鼠牙周炎动物模型龈沟液中细胞因子水平的变化及其与牙周指数的相关性.方法:将80 只SD大鼠随机分为4 组(缺氧对照组、缺氧实验组、常氧对照组及常氧实验组),每组20 只,成功建立大鼠牙周炎模型(缺氧实验组、常氧实验组)后,在常氧与低氧环境(模拟海拔5000 m高原、23 h /d)下饲养8 周,检测AL、PLI、BI等牙周临床指标,用ELISA法分别检测每组大鼠龈沟液中TNF-α、PGE2、IL-8的含量.结果:缺氧实验组龈沟液中TNF-α、PGE2水平明显高于其余各组(P<0.01),且与牙周指数呈正相关(P<0.01),而IL-8显著低于其他3 组(P<0.01),与AL、PLI呈负相关(P<0.01),与BI无相关(P>0.05).结论:模拟高原条件下,大鼠牙周炎模型龈沟液中TNF-α、PGE2水平较平原条件下升高,而IL-8减少,促使牙周组织炎症加重.     

Comparison of gingival health and gingival crevicular fluid flow in children with and without diabetes.

GCF flow measurements and a clinical scoring of gingival health were both recorded for a group of 56 children with diabetes and 41 children without diabets. The children with diabetes had significantly more gingival disease than the children without diabetes when compared with either measure. A small but significant correlation was found between the GCF flow and the clinical scores with the children with diabetes but not with the children without diabetes.     

Periodontitis‐specific molecular signatures in gingival crevicular fluid

Xiang XM, Liu KZ, Man A, Ghiabi E, Cholakis A, Scott DA. Periodontitis‐specific molecular signatures in gingival crevicular fluid. J Periodont Res 2010; 45: 345–352. © 2010 John Wiley & Sons A/S Background and Objective: Periodontitis is currently diagnosed almost entirely on gross clinical manifestations that have been in situ for more than 50 years without significant improvement. The general objective of this study was, therefore, to evaluate whether mid‐infrared spectroscopy can be used to identify disease‐specific molecular alterations to the overall biochemical profile of tissues and body fluids. Material and Methods: A total of 190 gingival crevicular fluid samples were obtained from periodontitis (n = 64), gingivitis (n = 61) and normal sites (n = 65). Corresponding infrared absorption spectra of gingival crevicular fluid samples were acquired and processed, and the relative contributions of key functional groups in the infrared spectra were analysed. The qualitative assessment of clinical relevance of these gingival crevicular fluid spectra was interpreted with the multivariate statistical analysis‐linear discriminant analysis. Results: Using infrared spectroscopy, we have been able to identify four molecular signatures (representing vibrations in amide I, amide II/tyrosine rings and symmetric and asymmetric stretching vibrations of phosphodiester groups in DNA) in the gingival crevicular fluid of subjects with periodontitis or gingivitis and healthy control subjects that clearly demarcate healthy and diseased periodontal tissues. Furthermore, the diagnostic accuracy for distinction between periodontally healthy and periodontitis sites revealed by multivariate classification of gingival crevicular fluid spectra was 98.4% for a training set of samples and 93.1% for a validation set. Conclusion: We have established that mid‐infrared spectroscopy can be used to identify periodontitis‐specific molecular signatures in gingival crevicular fluid and to confirm clinical diagnoses. Future longitudinal studies will assess whether mid‐infrared spectroscopy represents a potential prognostic tool, recognized as key to advancement of periodontics.