Oral Immunological Profile Impact on Local and Systemic DiseaseView this Special Issue
Research Article | Open Access
Quantification of TNF-α in Patients with Periodontitis and Type 2 Diabetes
Objective. The present study aimed to compare variations in quantified tumor necrosis factor-alpha (TNF-α) levels in patients with periodontitis stage 2 grade B (POD2B) and/or type 2 diabetes (T2D) and to identify any relationships between this cytokine and these diseases. Methods. Levels of the cytokine TNF-α in gingival crevicular fluid in patients with POD2B and/or T2D were evaluated. A total of 160 subjects were distributed into four groups: those with POD2B (n=44); those with T2D (n=37); those with POD2B/T2D (n=40); and healthy subjects (n=39). Glycosylated hemoglobin (HbA1c) and blood glucose (BG) levels were quantified in each subject. Data were collected on body mass index (BMI), loss of insertion (LI), and probe depth (PD). Gingival crevicular fluid samples were collected from the most acutely affected periodontal pocket and gingival sulcus in each subject, and TNF-α was quantified by multiplex analysis. Results. Kruskal Wallis tests was used to identify differences in TNF-α levels, LI, PD, BMI, BG, and HbA1c by group. Differences (p<0.001) were found for LI, PD, BG, and HbA1c. A Spearman test was used to calculate possible correlations between TNF-α levels and LI or PD identified a weak but significant negative correlation of TNF-α with LI (Rho=-0199; p=0.012), and a moderately positive correlation of LI with PD (Rho=0.509; p < 0.001). Conclusions. No variation was found between TNF-α levels and the presence of POD2B, POD2B/T2D, or T2D, suggesting the absence of any direct relationship between progression of these diseases and TNF-α levels. However, a correlation was present between low TNF-α concentrations and greater LI.
Diabetes mellitus is a public health problem in many countries. In medical terms, it encompasses a group of metabolic disorders with heterogeneous clinical and genetic characteristics, which manifest as abnormally high blood glucose levels. These disorders have a profound impact on health in affected individuals, causing high morbidity and mortality rates, and constitute an economic burden on health systems [1, 2]. The International Diabetes Federation states that China, India, the United States of America, Brazil, Russia, and Mexico have the highest number of diabetic patients . In 2012, diabetes was estimated to be the direct cause of 1.5 million deaths, and another 2.2 million deaths were attributable to hyperglycemia. Of these 3.7 million deaths, 43% occur in people less than 70 years old. Type 2 diabetes (T2D) accounts for 90 to 95% of cases worldwide and most commonly occurs in adults but is now increasingly common in children. By 2030, diabetes is projected to be the seventh cause of death worldwide [4, 5].
Periodontitis (POD) is the most common form of periodontal disease. It is more prevalent in adults but can occur in children. Although multifactorial in origin, three main factors are involved in POD appearance and evolution: accumulation of plaque and calculus; level of bacterial virulence; and cellular immune response . Evolution is slow to moderate, but more rapid periods of destruction can be observed, influenced mainly by systemic or environmental factors that can affect the normal interaction between host and bacteria . Plaque accumulation and host response to it can be affected by local factors such as systemic diseases (e.g., diabetes mellitus, HIV), which can depress host defenses, and the environment (e.g., smoking and stress) .
Both T2D and POD influence oral cavity health. Diabetes is a risk factor for gingivitis and POD when related to formation of a more persistent inflammatory infiltrate. An inverse influence may also exist in that POD could be a risk factor for diabetic decompensation . A complex bidirectional relationship between T2D and POD may occur that would create a vicious circle exacerbating both diseases when present simultaneously in the same individual [10–13].
Recent studies have been focused on the role of cytokines in periodontal diseases in diabetic patients. Cytokines are a group of cell regulators vital in the production and activation of effector cells that initiate and regulate different immune and inflammatory responses [14–16]. Tumor necrosis factor-alpha (TNF-α) is a proinflammatory mediator considered to be a soluble mediator released from immunocompetent cells. It exercises a wide range of proinflammatory and immunomodulatory effects in different cell populations, such as stimulating prostaglandin synthesis, promoting tumors in a variety of cancers, producing proteases, and activating osteoclastic function and therefore bone resorption. Its myriad functions suggest that TNF-α plays an important role in mediating the immune-inflammatory responses initiated by infection or other types of damage . During its initial production in the inflammatory response, TNF-α is also vital for maintaining chronic inflammation, angiogenesis, tissue remodeling, tumor growth, and metastasis; TNF-α blockers are therefore effective in treating a variety of acute and chronic inflammatory conditions .
An important proinflammatory cytokine and immune response modulator, TNF-α production occurs in response to stimuli from cell types such as macrophages, neutrophils, keratinocytes, adipocytes, fibroblasts, and NK, T and B cells. High serum levels of this cytokine have been detected in patients with POD, suggesting it may be contributing to pathogenesis. Its activation also stimulates bone resorption by induction in osteoclast progenitor proliferation, and production of extracellular matrix metalloproteinases, cytokines, collagenase, and prostaglandins [19–22].
The aim of this study was to compare the variations in quantified TNF-α levels in patients with POD and/or T2D and to identify any relationships between this cytokine and these diseases.
2. Materials and Methods
A cross-sectional study was done and approved by the Institutional Bioethics Committee. Subjects were selected from the Admission Dental Clinic, Faculty of Dentistry, Autonomous University of Yucatan (UADY); after explanation of the procedure, those choosing to participate signed an informed consent.
Presence of T2D was identified based on the 2019 American Diabetes Association parameters : glycosylated hemoglobin (HbA1c) values ≥ 6.5% indicate diabetes and those ≤ 5.6% are normal; glucose blood (GB) levels (8 to 10 hours) ≥ 126 mg/dL indicate diabetes and those ≤ 100 mg/dL are normal.
According to specific classification for periodontal and peri-implant diseases and conditions, patients included were targeted with stage 2, grade B POD . Periodontal probing with a calibrated periodontal probe was done (UNC-15, Hu-Friedy, Chicago, IL, USA); all teeth were examined except third molars. Subjects were excluded who had received periodontal treatment, chemotherapy, and antibiotic and/or anti-inflammatory treatment in the six months prior to examination or exhibited systemic diseases other than T2D. From a total of 160 selected subjects, four study groups were formed: group 1 (POD2B, n=44); group 2 (T2D, n=37); group 3 (POD2B/T2D, n=40); and group 4 (control with healthy subjects exhibiting no periodontal disease, n=39). Gingival crevicular fluid (GCF) samples were collected from periodontal pockets with ≥ 4 mm depth and ≤ 3 mm insertion loss in groups 1 and 3, and from the mesiovestibular gingival sulcus of the first lower molar in groups 2 and 4. Samples were collected by first isolating the tooth with a cotton impeller and removing the supragingival plaque with a curette (Gracey, Hu-Friedy, Chicago, IL, USA), avoiding injury to the marginal gingiva. After slightly drying the crevicular site with air, GCF was obtained by inserting a PerioPaper strip (PerioPaper, ProFlow, Amityville, NY, USA) into the sulcus or periodontal pocket to the point of resistance and leaving it there for thirty seconds. Strips contaminated with saliva or blood were discarded and a new sample taken at a different site. After collection, the PerioPaper strips were immediately placed in sterile Eppendorf vessels and stored at -70°C until analysis. The GCF was extracted by two elution methods in 0.05% PBS-T solution followed by centrifuging at 12,000 g for 5 minutes and at 4°C, until reaching a final elution volume of 80 μL. Of this volume, 40 μL were tested with Luminex platform (Magpix, Millipore, St. Charles, MO, USA) and analyzed with a MILLIPLEX analyst software (ViageneTech, Carlisle, MA, USA). Results were expressed per mL of elution to measure TNF-α levels in the total amount (pg) and concentration volume according to the formula TNF-α (pg)/volume (μL).
Kruskal-Wallis test was applied to identify any differences in the data for TNF-α, loss of insertion (LI, %), probe depth (PD), body mass index (BMI), blood glucose (BG), and glycosylated hemoglobin (HbA1c) by group. A Spearman test was used to evaluate the possible existence of a correlation between TNF-α count and LI or PD (statistical significance p≤0.05).
Analysis of the BMI, BG, and HbA1c data showed 31.87% of the total sample to exhibit glycemic levels outside normal levels (Table 1). In the comparison between groups, BG and HbA1c had different values (p<0.001). Paired comparisons for BG identified differences (p<0.001) between Control-T2D, Control-POD2B/T2D, POD2B-T2D, and POD2B-POD2B/T2D. For HbA1c, differences (p<0.001) were found between POD2B-T2D, POD2B-POD2B/T2D, Control-T2D, and Control-POD2B /T2D. The T2D and POD2B/T2D groups had the highest values (Table 1).
BMI: Body mass index; BG: Blood glucose; HbA1c: Glycosylated hemoglobin; p=0.001
Analysis of periodontal condition identified differences between groups for LI and PD (p<0.001), with the highest values in both cases being in POD2B and POD2B/T2D (Table 2). No differences in TNF-α concentration were found between groups. A Spearman test identified a weak but significant negative correlation between TNF-α levels and LI (Rho=-0.199; p=0.012), and a moderate but significant positive correlation between LI and PD (Rho=0.509; p<0.001).
LI: Loss of insertion; PD: probe depth; Kruskal Wallis test p=0.001; Spearman test p=0.001
There are multiple conditions that can affect the periodontal health. Locally, factors such as dental malposition, poorly adjusted restorations, maxillofacial fractures, and uncontrolled use of chlorhexidine-based products have been reported [25, 26]. Likewise, several systemic conditions have been reported that influence the periodontal status of patients, among which T2D, hypertension, hemophilia, leukemia, and certain digestive disorders can be mentioned [27–29]. All these conditions have been studied separately, observing important changes in the evolution of periodontitis and the associated immunological factors.
TNF-α is an important proinflammatory cytokine and modulator of the immune response. It is produced in response to stimuli from cell types such as macrophages, neutrophils, keratinocytes, adipocytes, fibroblasts, and NK, T and B cells. High serum TNF-α levels have been detected in patients with POD since it contributes to disease pathogenesis. This cytokine stimulates bone resorption by inducing osteoclast progenitor proliferation, as well as production of chemokine, extracellular matrix metalloproteinases, cytokines, collagenase, and prostaglandins. Cytokine concentration in GCF has been linked to degree of glycemic control in diabetic patients [19–22].
Studies have shown that diabetic patients with periodontal infection have a higher risk of losing control of their glycemic condition; and this deteriorates over the long term compared to diabetic patients who do not suffer POD [30–32]. In the course of periodontal disease, various proinflammatory mediators occur, such as interleukin- (IL-) 1, IL-6, and IL-8, IFN- γ, CCL5, TNF-α, prostaglandins, and metalloproteinases. These mediators alter the activity of leukocytes and osteoblasts-osteoclasts and promote the tissue remodeling process both locally and systemically. The proinflammatory cytokine TNF-α regulates production of collagenase, prostaglandin E2, molecular adhesion cells, and factors related to bone resorption. Secreted mainly by monocytes and macrophages, elevated TNF-α levels have been observed in chronic gingival inflammation processes and in GCF in patients with POD [9, 33, 34].
No intergroup differences in TNF-α concentration were observed in the present study. This is similar to the lack of differences in TNF-α concentration in the GCF between patients with POD2B, aggressive POD, or systemically healthy patients reported in a Turkish population . However, in the present study, differences were present between groups in terms of LI and PD, with the POD2B and POD2B/T2D groups having the highest values. These results agree with a study of the progression of periodontal lesion in which no differences in TNF-α concentration were observed when comparing active and inactive sites in 56 patients in a Chilean population diagnosed with moderate to advanced chronic POD [36, 37]. They also agree with a study done in Brazil in which no differences in TNF-α concentration was noted between POD2B/T2D and POD2B patients [38, 39].
Increases in TNF-α concentration in patients with POD2B/T2D or POD2B have also been described in a Portuguese population, but with no differences between groups [40, 41], like the present results. A study in Korean patients found no correlation between TNF-α levels and gingival tissues in patients with POD [30, 31]. The lack of difference in the present results may have occurred because 68.13% of the patients exhibited good glycemic control. This can translate into low TNF-α expression in POD2B/T2D patients because hyperglycemia can overregulate levels of TNF-α, and other cytokines such as GM-CSF and IL-6, in both healthy and periodontal affected tissues [42, 43]. This overregulation also enhances epithelial cell stimulation capacity by providing an inflammatory system that must be interrupted for the disease to improve; this interruption can occur when hyperglycemia is controlled or when a periodontal disease enters remission .
Reis et al. found no differences in TNF-α levels in patients with or without POD2B, and neither did they observe decreases in TNF-α levels after nonsurgical periodontal treatment . In another study, quantification of cytokine expression in diseased peri-implant tissue found no differences in TNF-α concentrations between sites with mucositis and peri-implantitis in both GCF and saliva . In a comparison of different treatments in residual pockets using the final concentration of acute-phase proteins, no changes were found in TNF-α concentration between data from the baseline condition, at 14 days and at 6 months .
Duarte et al. found significant differences between TNF-α concentration and T2D when comparing healthy and infected sites in patients with and without T2D [40, 47]. This differs from the lack of difference in the present results, perhaps because BG levels in the present study subjects were not very high and 68.13% of the subjects exhibited adequate glycemic control. Expression of TNF-α can be attributed to an increase in RAGE or expression of TLR4, which directly affect the response of epithelial cells and their antagonists inducing the proinflammatory cytokine response, as well as an increase in cell surface receiving capacity . These receptors also work collaboratively to induce expression of these cytokines in oral epithelial cells, although this collaboration is not involved in inducing innate immunity receptors. Indeed, a correlation exists between a lack of control of blood sugar levels and deficiency in the epithelial barrier which translates into an increase in expression of the immune receptors of the innate immune response and an exacerbated inflammatory response .
Increases in TNF-α concentrations have been reported after nonsurgical periodontal treatment, with higher levels in healthy subjects than in unhealthy patients . These results coincide with the present results in which higher TNF-α levels were observed in healthy subjects than in the POD2B, POD2B/T2D, and T2D groups. A possible explanation for these reduced inflammatory protein levels in patients with these chronic diseases is that host immune response may be diminished.
Interstudy variation in TNF-α concentrations may be due to several factors including periodontal disease severity, subject age, sample type, population type, and technique details such as storage temperature and pretest storage time .
GCF has been widely used as a diagnostic tool for various periodontal diseases. Available evidence indicates that GCF can influence the progression of periodontal diseases when combined with systemic diseases, suggesting that local changes in GCF can be reflected as systemic inflammation through direct expression of circulating inflammatory mediators . The presence of T2D plays a fundamental role in development of chronic POD. Its resistance and control can affect TNF-α concentrations, possibly explaining the contrasts between different studies mentioned previously.
The present results indicate that good control of BG in patients with POD2B/T2D can directly influence expression of the TNF-α cytokine; however, low TNF-α concentrations are directly correlated with greater insertion loss and probe depth.
The general and clinical characteristics of sample used to support the findings of this study are included within the article.
Conflicts of Interest
No potential conflicts of interest relevant to this article were reported.
This work was supported partially by UADY-EXB-214, PFCE-UASLP, and PRODEP grants.
- C. C. Cowie, K. F. Rust, D. D. Byrd-Holt et al., “Prevalence of diabetes and impaired fasting glucose in adults in the U.S. population: national Health and Nutrition Examination Survey 1999–2002,” Diabetes Care, vol. 29, no. 6, pp. 1263–1268, 2008.
- T. Kathiresan, K. Masthan, R. Sarangarajan, N. Babu, and P. Kumar, “A study of diabetes associated oral manifestations,” Journal of Pharmacy & Bioallied Science, vol. 9, no. 1, pp. 21–26, 2017.
- Y.-Y. Wu, E. Xiao, and D. T. Graves, “Diabetes mellitus related bone metabolism and periodontal disease,” International Journal of Oral Science, vol. 7, no. 2, pp. 63–72, 2015.
- B. L. Mealey and G. L. Ocampo, “Diabetes mellitus and periodontal disease,” Periodontology 2000, vol. 18, no. 2, pp. 86–104, 2008.
- Informe Mundial sobre la Diabetes. Organización Mundial de la Salud, 2016.
- Secretaría de Salud; Subsecretaría de Prevención y Promoción de la Salud y Dirección General de Epidemiología; Encuesta Nacional de Salud y Nutrición 2014 (ENSANUT), México, 2014.
- A. N. Gurav, “Management of diabolical diabetes mellitus and periodontitis nexus: are we doing enough?” World Journal of Diabetes, vol. 7, no. 4, pp. 50–66, 2016.
- J. C. Pickup and M. A. Crook, “Is type II diabetes mellitus a disease of the innate immune system?” Diabetologia, vol. 41, no. 10, pp. 1241–1248, 2007.
- F. Llambés, “Relationship between diabetes and periodontal infection,” World Journal of Diabetes, vol. 7, no. 7, pp. 927–935, 2015.
- P. M. Preshaw, N. Foster, and J. J. Taylor, “Cross-susceptibility between periodontal disease and type 2 diabetes mellitus: an immunobiological perspective,” Periodontology 2000, vol. 45, no. 1, pp. 138–157, 2007.
- R. Mesia, F. Gholami, H. Huang et al., “Systemic inflammatory responses in patients with type 2 diabetes with chronic periodontitis,” BMJ Open Diabetes Research & Care, vol. 4, no. 1, Article ID e000260, 2016.
- A. D. Haffajee and S. S. Socransky, “Microbial etiological agents of destructive periodontal diseases,” Periodontology 2000, vol. 5, pp. 78–111, 1994.
- M. M. Azuma, P. Balani, H. Boisvert et al., “Endogenous acid ceramidase protects epithelial cells from Porphyromonas gingivalis -induced inflammation in vitro,” Biochemical and Biophysical Research Communications, vol. 495, no. 4, pp. 2383–2389, 2018.
- L. A. Crocombe, D. S. Brennan, G. D. Slade, and D. O. Loc, “Is self interdental cleaning associated with dental plaque levels, dental calculus, gingivitis and periodontal disease?” Journal of Periodontal Research, vol. 47, no. 2, pp. 188–197, 2012.
- V. Baelum and R. López, “Periodontal disease epidemiology-learned and unlearned?” Periodontology 2000, vol. 62, no. 1, pp. 37–58, 2013.
- F. Farías-Rodríguez, “Enfermedad periodontal y microorganismos periodontopatógenos,” ODOUS científica (Venezuela), vol. 6, no. 10, pp. 25–36, 2009.
- G. Koshy, E. f. Corbet, and I. Ishikawa, “A full-mouth disinfection approach to nonsurgical periodontal therapy - prevention of reinfection from bacterial reservoirs,” Periodontology 2000, vol. 36, no. 1, pp. 166–178, 2004.
- J. Gamonal, A. Acevedo, A. Bascones, O. Jorge, and A. Silva, “Levels of interleukin-1β, -8, and -10 and RANTES in gingnival crevicular fluid and cell populations in adult periodontitis patients and the effect of periodontal treatment,” Journal of Periodontology, vol. 71, no. 10, pp. 1535–1545, 2000.
- J. Gamonal, A. Bascones, O. Jorge, and A. Silva, “Chemokine RANTES in gingival crevicular fluid of adult patients with periodontitis,” Journal of Clinical Periodontology, vol. 27, no. 9, pp. 675–681, 2000.
- E. Gemmell, C. L. Carter, and G. J. Seymour, “Chemokines in human periodontal disease tissues,” Clinical & Experimental Immunology, vol. 125, no. 1, pp. 134–141, 2001.
- L. Savarrio, M. Donati, C. Carr, D. F. Kinane, and T. Berglundh, “Interleukin-24, RANTES and CCR5 gene polymorphisms are not associated with chronic adult periodontitis,” Journal of Periodontal Research, vol. 42, no. 2, pp. 152–158, 2007.
- D. H. Thunell, K. D. Tymkiw, G. K. Johnson et al., “A multiplex immunoassay demonstrates reductions in gingival crevicular fluid cytokines following initial periodontal therapy,” Journal of Periodontal Research, vol. 45, no. 1, pp. 148–152, 2010.
- American Diabetes Association, “Classification and diagnosis of diabetes: Standards and medical cares in diabetes 2019,” Diabetes Care, vol. 42, no. Supplement 1, pp. S13–S28, 2019.
- P. N. Papapanou, M. Sanz, N. Buduneli, T. Dietrich, M. Feres, D. Fine et al., “Periodontitis: consensus report of workgroup 2 of the 2017 world workshop on the classification of periodontal and peri-implant diseases and conditions,” Journal of Clinical Periodontology, vol. 89, no. 1, pp. 173–182, 2018.
- F. Fama, M. Cicciu, A. Sindoni et al., “Maxillofacial and concomitant serious injuries: an eight-year single center experience,” Chinese Journal of Traumatology (English Edition), vol. 20, no. 1, pp. 4–8, 2017.
- L. Fiorillo, “Chlorhexidine gel use in the oral district: a systematic review,” Gels, vol. 5, no. 2, p. 31, 2019.
- G. Cervino, L. Fiorillo, L. Laino et al., “Oral health impact profile in celiac patients: analysis of recent findings in a literature review,” Gastroenterology Research and Practice, vol. 2018, Article ID 7848735, 9 pages, 2018.
- G. Cervino, A. Terranova, F. Briguglio et al., “Diabetes: oral health related quality of life and oral alterations,” BioMed Research International, vol. 2019, Article ID 5907195, 14 pages, 2019.
- L. Fiorillo, R. De Stefano, G. Cervino et al., “Oral and psychological alterations in haemophiliac patients,” Biomedicines, vol. 7, no. 2, p. 33, 2019.
- M. K. Noh, M. Jung, S. H. Kim et al., “Assessment of IL-6, IL-8 and TNF-α levels in the gingival tissue of patients with periodontitis,” Experimental and Therapeutic Medicine, vol. 6, no. 3, pp. 847–851, 2013.
- M. B. Grauballe, J. A. Ostergaard, S. Schou, A. Flyvbjerg, and P. Holmstrup, “Effects of TNF-α blocking on experimental periodontitis and type 2 diabetes in obese diabetic Zucker rats,” Journal of Clinical Periodontology, vol. 42, no. 9, pp. 807–816, 2015.
- K. Izuora, E. Ezeanolue, K. Schlauch, M. Neubauer, C. Gewelber, and G. Umpierrez, “Impact of periodontal disease on outcomes in diabetes,” Contemporary Clinical Trials, vol. 41, pp. 1–7, 2015.
- L. Fiorillo, G. Cervino, A. S. Herford et al., “Interferon crevicular fluid profile and correlation with periodontal disease and wound healing: A systemic review of recent data,” International Journal of Molecular Sciences, vol. 19, no. 7, p. 1908, 2018.
- L. Sansores-España, A. Carrillo-Avila, E. Sauri-Esquivel, E. Guzman-Marin, M. Hernandez, A. Pozos-Guillén et al., “Quantification of chemokine CCL5 in patients with diabetes mellitus type 2 and/or chronic periodontitis: preliminary study,” ODOVTOS- International Journal of Dental Science, vol. 19, no. 2, pp. 41–48, 2017.
- Ö. Özer-Yücel, E. Berker, L. Mesci, K. Eratalay, E. Tepe, and İ. Tezcan, “Analysis of TNF-α (-308) polymorphism and gingival crevicular fluid TNF-α levels in aggressive and chronic periodontitis: a preliminary report,” Cytokine, vol. 72, no. 2, pp. 173–177, 2015.
- N. Silva, N. Dutzan, M. Hernandez et al., “Characterization of progressive periodontal lesions in chronic periodontitis patients: levels of chemokines, cytokines, matrix metalloproteinase-13, periodontal pathogens and inflammatory cells,” Journal of Clinical Periodontology, vol. 35, no. 3, pp. 206–214, 2008.
- P. M. Bartold and A. S. Narayanan, “Molecular and cell biology of healthy and diseased periodontal tissues,” Periodontology 2000, vol. 40, no. 1, pp. 29–49, 2006.
- F. Vieira-Ribeiro, A. C. de Mendoncxa, V. R. Santos, M. F. Bastos, L. C. Figueiredo, and P. M. Duarte, “Cytokines and bone-related factors in systemically healthy patients with chronic periodontitis and patients with type 2 diabetes and chronic periodontitis,” Journal of Periodontology, vol. 82, no. 8, pp. 1187–1196, 2011.
- M. de Groot, M. B. Teunissen, J. P. Ortonne et al., “Expression of the chemokine receptor CCR5 in psoriasis and results of a randomized placebo controlled trial with a CCR5 inhibitor,” Archives of Dermatological Research, vol. 299, no. 7, pp. 305–313, 2007.
- A. B. Navarro-Sanchez, R. Faria-Almeida, and A. Bascones-Martinez, “Effect of non-surgical periodontal therapy on clinical and immunological response and glycaemic control in type 2 diabetic patients with moderate periodontitis,” Journal of Clinical Periodontology, vol. 34, no. 10, pp. 835–843, 2007.
- Y. Kato, R. Pawankar, Y. Kimura, and S. Kawana, “Increased expression of RANTES, CCR3 and CCR5 in the lesional skin of patients with atopic eczema,” International Archives of Allergy and Immunology, vol. 139, no. 3, pp. 245–257, 2006.
- J. Amir, M. Waite, J. Tobler et al., “The role of hyperglycemia in mechanisms of exacerbated inflammatory responses within the oral cavity,” Cellular Immunology, vol. 272, no. 1, pp. 45–52, 2011.
- L. Kardeşler, N. Buduneli, Ş. Çetinkalp, D. Lappin, and D. F. Kinane, “Gingival crevicular fluid IL-6, tPA, PAI-2, albumin levels following initial periodontal treatment in chronic periodontitis patients with or without type 2 diabetes,” Inflammation Research, vol. 60, no. 2, pp. 143–151, 2011.
- C. Reis, A. Viana da, J. T. Costa, D. Tuna, A. C. Braga, J. J. Pacheco et al., “Clinical improvement following therapy for periodontitis: Association with to decrease in IL-1 and IL-6,” Experimental and Therapeutic Medicine, vol. 8, no. 1, pp. 323–327, 2014.
- F. J. P. Oliva, M. Moraes, E. J. Veras, D. de Moraes, and C. M. Figueredo, “Cytokines expression in saliva and peri-implantitis crevicular fluid of patients with peri-implantitis disease,” Clinical Oral Implants Research, vol. 25, no. 2, pp. 68–72, 2012.
- C. Giannopoulou, I. Cappuyns, J. Cancela, N. Cionca, and A. Mombelli, “Effect of photodynamic therapy, diode laser, and deep scaling on cytokine and acute-phase protein levels in gingival crevicular fluid of residual periodontal pockets,” Journal of Periodontology, vol. 83, no. 8, pp. 1018–1027, 2012.
- P. M. Duarte, J. P. Bezerra, T. S. Miranda, M. Feres, L. Chambrone, and L. M. Shaddox, “Local levels of inflammatory mediators in uncontrolled type 2 diabetic subjects with chronic periodontitis,” Journal of Clinical Periodontology, vol. 41, no. 1, pp. 11–18, 2014.
- M. C. Medeiros, S. C. T. Frasnelli, A. D. S. Bastos, S. R. P. Orrico, and C. Rossa Jr., “Modulation of cell proliferation, survival and gene expression by RAGE and TLR signaling in cells of the innate and adaptive immune response: role of p38 MAPK and NF-KB,” Journal of Applied Oral Science, vol. 22, no. 3, pp. 185–193, 2014.
- P. Mayank, P. Sapan, P. Mayur, S. Foram, P. Bhavin, and J. Jigar, “Comparison of level of pentraxin-3 in gingival crevicular fluid with chronic periodontitis in well controlled and uncontrolled diabetes mellitus patients,” National Journal of Integrated Research in Medicine, vol. 9, no. 2, pp. 31–35, 2018.
- M. Eivazi, N. Falahi, N. Eivazi, M. A. Eivazi, A. V. Raygani, and F. Rezaei, “The effect of scaling and root planning on salivary TNF-α and IL-1α concentrations in patients with chronic periodontitis,” The Open Dentistry Journal, vol. 11, pp. 573–580, 2017.
- K. D. Tymkiw, D. H. Thunell, G. K. Johnson et al., “Influence of smoking on gingival crevicular fluid cytokines in severe chronic periodontitis,” Journal of Clinical Periodontology, vol. 38, no. 3, pp. 219–228, 2011.
- M. S. Gomes, T. C. Blattner, M. Sant'Ana Filho, F. S. Grecca, F. N. Hugo, and A. F. Fouad, “Can apical periodontitis modify systemic levels of inflammatory markers? a systematic review and meta-analysis,” Journal of Endodontics, vol. 39, no. 10, pp. 1205–1217, 2013.
Copyright © 2019 Víctor M. Martínez-Aguilar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.