Journal of Indian Society of Periodontology
Journal of Indian Society of Periodontology
Home | About JISP | Search | Accepted articles | Online Early | Current Issue | Archives | Instructions | SubmissionSubscribeLogin 
Users Online: 3201  Home Print this page Email this page Small font size Default font size Increase font sizeWide layoutNarrow layoutFull screen layout

   Table of Contents    
Year : 2021  |  Volume : 25  |  Issue : 6  |  Page : 485-490  

Effect of nonsurgical periodontal therapy on C-reactive protein and iron indices in hemodialysis patients

1 Department of Periodontology, Sree Mookambika Institute of Dental Sciences, Thrissur, Kerala, India
2 Department of Nephrology, Sree Mookambika Institute of Medical Sciences, Kanyakumari, Tamil Nadu, India
3 Department of Periodontology, P.S.M College of Dental Science and Research, Thrissur, Kerala, India

Date of Submission16-Jan-2020
Date of Decision13-Mar-2021
Date of Acceptance02-Apr-2021
Date of Web Publication01-Nov-2021

Correspondence Address:
Sheethel Menon Vrinda
Sree Mookambika Institute of Dental Sciences, V.P.M Hospital Complex, Padanilam, Kulasekharam, Kanniyakumari - 629 161, Tamil Nadu
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jisp.jisp_32_20

Rights and Permissions

Background and Aim: The aim of the study was to evaluate the effect of nonsurgical periodontal therapy on clinical, renal, and hematological parameters at baseline and 3 months postoperatively on chronic kidney disease (CKD) patients undergoing hemodialysis. This comparative interventional study was conducted among CKD patients undergoing hemodialysis. Materials and Methods: This study included chronic periodontitis (CP) patients divided into three groups Group I: CKD patients undergoing hemodialysis for less than a year; Group II: CKD patients undergoing hemodialysis for more than a year; and Group III: systemically healthy CP patients. Clinical parameters (bleeding on probing [BOP], probing pocket depth (PPD), and clinical attachment level [CAL]) were recorded at baseline (T0), 1 month (T1), and 3 months after scaling and root planing (SRP) (T2). C-reactive protein (CRP) and transferrin saturation (TSAT) were observed at T0 and at T2. Paired t-test and Chi-square test were applied to find the statistical significance (P < 0.05 was considered statistically significant at 95% confidence interval) between the T0 and T2 time within the groups. Results: Clinical parameters such as PPD and CAL decreased with statistical significance in Group III alone, whereas BOP decreased with statistical significance in all the three groups. The study showed statistically significant reduction of CRP (in Group I and Group III) and TSAT increased with statistical significance in all the three groups after SRP. Conclusion: This suggests that SRP can bring an improvement in the systemic markers in CP patients under hemodialysis. However, we need a longitudinal study with a larger sample size to confirm the results.

Keywords: Dialysis, inflammation, periodontitis, renal insufficiency, treatment

How to cite this article:
Vrinda SM, Sadasivan A, Koshi E, Unnikrishnan B, Chandradas ND, Saraswathi IR. Effect of nonsurgical periodontal therapy on C-reactive protein and iron indices in hemodialysis patients. J Indian Soc Periodontol 2021;25:485-90

How to cite this URL:
Vrinda SM, Sadasivan A, Koshi E, Unnikrishnan B, Chandradas ND, Saraswathi IR. Effect of nonsurgical periodontal therapy on C-reactive protein and iron indices in hemodialysis patients. J Indian Soc Periodontol [serial online] 2021 [cited 2022 Jul 2];25:485-90. Available from:

   Introduction Top

Periodontitis is a slowly progressive inflammatory condition that augments the circulating levels of systemic inflammatory mediators such as C-reactive protein (CRP) in individuals with chronic kidney disease (CKD).[1] CKD advances to end-stage renal disease (ESRD) which actually necessitates dialysis and/or kidney transplantation when the kidney function decreases normal efficiency by < 10%.[2] Dialysis is performed to eliminate excessive fluids, electrolytes, and uremic contaminants. Nonsurgical periodontal therapy (NSPT) such as scaling and root planing (SRP)[3] improves, in conjunction with the systemic inflammatory markers, the periodontal disease state.[4],[5] In a study, Kumar et al.[6] showed that CRP levels in gingival crevicular fluid decreased after NSPT in chronic periodontitis (CP). A research by Vilela et al.[7] evaluated the CRP levels prior to and after NSPT and found a significant decrease in marker levels after treatment.

The purpose of this research was therefore to check in CP patients the impact of NSPT on clinical parameters, CRP, iron indices and renal and hematological parameters. These parameters were compared in CKD patients undergoing dialysis and systemically stable CP patients.

   Materials and Methods Top

This interventional study is done to compare the levels of CRP and iron indices before and after SRP in CKD patients under hemodialysis (with CP) and in systemically stable CP patients. The research included patients with ESRD undergoing hemodialysis at Sree Mookambika Institute of Medical Sciences (SMIMS), Kanyakumari District, and systemically stable individuals with CP were selected from the outpatients of the Periodontics Department, Sree Mookambika Institute of Dental Sciences (SMIDS), Kanyakumari District, Tamil Nadu. Approval of our research protocol was rendered by the Ethics Committee of our institute and registration done under the Clinical Trial Registry of India (CTRI/2017/12/010727). This study was done in consistence with the 1975 Declaration of Helsinki, as changed in 2000. The sample size of minimum 18 for each group was calculated based on the results got from the research by Vilela et al.[7] This research only involved patients with CP. Participants were grouped into Group I: twenty CKD patients who have been on hemodialysis for <1 year, Group II: twenty CKD patients who have been on hemodialysis for more than 1 year, and Group III: twenty systemically healthy individuals. The procedure of the research was explained to all and their informed consent was obtained.

Patients were considered to be CP when more than 30% of teeth were affected with attachment loss ≥ 5mm[8] along with occurrence of bleeding on probing(BOP). The research exempted pregnant women, lactating mothers, smokers, alcoholics, and patients who have undergone some form of periodontal therapy during the past 6 months. Six locations of every teeth (mesiobuccal, distobuccal, mid buccal, mesiolingual, distolingual, and mid lingual) were checked for the clinical parameters using a graded periodontal probe (University of Michigan O' probe with Williams markings) at the initial evaluation (T0), 4 weeks (T1), and 3 months (T2) after NSPT. Gingival index (GI),[9] plaque index (PI),[10] probing pocket depth (PPD), BOP,[11] and clinical attachment level (CAL) were the clinical parameters that were checked. Iron indices included serum ferritin and transferrin saturation ratio (TSAT). Renal parameters evaluated were CRP, serum albumin, glomerular filtration rate (GFR) and serum creatinine, and the hematological parameters were hemoglobin (Hb) and erythrocyte sedimentation rate (ESR). Once patients were chosen based on the criteria for inclusion, blood samples were taken and the estimation of renal and hematological parameters was done. After recording the clinical parameters from all included patients, NSPT was performed by SRP. An ultrasonic scaler and Gracey curettes were used to perform SRP under local anesthesia. After a month, patients were called back for assessing the clinical parameters alone (T1) and after 3 months for assessing clinical parameters, iron indices, and renal and hematological parameters (T2). The study design is given in [Figure 1].
Figure1: Study design; n - number of participants

Click here to view

Sample collection

From all patients, venous blood of 5 mL was taken through venepuncture in the cubital fossa. The sample was collected at T0 and at T2. The serum obtained from collected blood was used to calibrate renal parameters, iron indices, and blood parameters.


The estimation of renal parameters, iron indices, and blood parameters from the collected sample was at the Central Laboratory, SMIMS.

Analysis method and normal range/values of each parameter:

  1. Star 21 Plus Auto Analyzer by the immunoturbidimetry method was used to estimate the serum CRPs levels. A value <5 mg/L was considered negative
  2. TSAT is obtained as a percentage from the ratio of serum iron and total iron-binding capacity (TIBC) and is a medical laboratory value. Average TSAT is about 25%
  3. Beckman Coulter AU 480 analyzer was used to estimate TIBC, serum iron, creatinine, and albumin: reference range for serum iron is 60–170 μg/dL, for TIBC is 240–450 μg/dL, for creatinine is 0.6–1.2 mg/dL, and for albumin is 3.4–5.4g/dL
  4. Beckman Coulter access 2 immunoassay system with chemiluminescent detection method was used to estimate serum. Reference range: adult male: 20–250 ng/mL and for adult females: 10–120 ng/mL
  5. For young adults, the usual mean GFR is approximately 90–120 mL/min/1.73m2. GFR is computed by the modification of diet in renal disease study equation

  6. GFR (mL/min/1.73 m2) = 175 × (serum creatinine)−1.154 × (Age)−0.203 × (0.742 for females)

  7. Automated hematology analyzer for Hb estimation and Beckman Coulter AcT 5diff CP and Mindray BC 5300 5 diff for ESR estimation (colorimetric method is used for determining Hb and Westergren method for ESR). The typical range of Hb for men is 13.5–17.5 g/dL and for women is 12 to 15.5 g/dL and of ESR 0–22 mm/h for men and 0–29 mm/h for women.

Statistical analysis

The Statistical Package for the Social Sciences (SPSS package version 16.0, Inc., an IBM Company, Chicago, Illinois, USA) was used to analyze the obtained data. The statistical significance between the parameters at T0 and after therapy within the groups was found with the paired t-test and the Chi-square test. P ≤ 0.05 at 95% confidence interval was perceived to be statistically significant.

   Results Top

[Table 1] summarizes demographic as well as the clinical observations of all three groups. [Table 2] and [Table 3] show how the clinical parameters are compared at different time periods within the groups. A statistically significant decrease was noted in PI and BOP at different time periods in Group I and II; however, a statistically significant reduction in all clinical parameters such as including GI, PPD, and CAL was found in Group III at 3 month post treatment when compared to T0. The levels of CRP, serum albumin, and ferritin before and after treatment within each group are given in [Table 4]. The levels of CRP were decreased with statistical significance in Group I and III at T2 from that of T0. Increase in serum ferritin was with statistical significance in Group II and III at T2 compared to T0, but a decrease with statistical significance was noted in Group III after 3 months of treatment. In Group I, II, and III, with respect to the albumin levels, there was not any statistically significant change. [Table 5] shows 3 months after SRP, serum iron increased with statistical significance in Group I and III with respect to the baseline levels, whereas in Group II, no statistical difference was seen. A statistically significant increase in TSAT was observed in all three groups at T2 compared to baseline.
Table 1: Comparison of demographic and clinical observations of the groups

Click here to view
Table 2: Comparison of mean clinical parameters (plaque index, gingival index, and bleeding on probing) at different time periods within the groups

Click here to view
Table 3: Comparison of mean clinical parameters (probing pocket depth and clinical attachment level) at different time periods within the groups

Click here to view
Table 4: Comparison of mean C-reactive protein, serum ferritin, and serum albumin levels at different time periods within the groups

Click here to view
Table 5: Comparison of iron, total iron binding capacity, and transferrin saturation values at different time periods within the groups

Click here to view

[Table 6] shows 3 months after treatment, in serum creatinine, no statistically significant change was observed in all the three Groups. A shift with statistical significance was not found in Group I and II after 3 months with regard to GFR, while a change with statistical significance was observed in Group III. [Table 7] shows the variation in Hb and ESR in all the three groups, with Hb changes not statistically significant in any of the groups at T2 in comparison to baseline, but statistically significant changes in ESR values in all three groups at T2 in comparison to baseline were noted.
Table 6: Comparison of mean creatinine and glomerular filtration rate values at different time periods within the groups

Click here to view
Table 7: Comparison of hematological parameters at different time periods within the groups

Click here to view

   Discussion Top

CKD is characterized by a gradual and cumulative loss of kidney function[12] which, in turn, can affect the periodontal tissue.[13] Periodontal disease occurs in vulnerable people[14] and leads to an increased systemic inflammatory burden in patients with CKD.[15],[16],[17] Studies have revealed that successful periodontal treatment can bring about a decrease in the circulating inflammatory markers in patients with and without CKD.[7],[15],[18]

PI is a simple procedure to observe an individual's capability to control plaque to form on the tooth surface. PI score decreased from baseline, after which a marginal increase at T2 was observed in Group I and II and this illustrated the weak compliance to the oral hygiene instructions. This is similar to the research by Wehmeyer et al.,[19] in which a fall in PI at 3 months after treatment accompanied by a rise in the hemodialysis population at 6 months was noted. GI is a method to find out the intensity of gingival inflammation. In Group I and II, though not statistically significant, GI decreased from T0 to T2. BOP is a valid measure of gingival inflammation and has decreased significantly in Group I and II from T0 to T2. In Group I and II, PPD and CAL were also noted to be decreased without statistical significance from baseline to T2.

Akin to the study by Graziani et al.[20] and Artese et al.[21] in Group III, all the clinical parameters (PI, BOP, GI, PPD, and CAL) declined with statistical significance at T2. The findings of these studies reported a substantial decline in clinical parameters post treatment in systemically stable CP patients. In contrast to Group I and II, Group III has a better compliance with the given oral hygiene instructions.

The CRP levels in Group I and III declined with statistical significance at T2 from T0, while the decline was not with statistical significance in Group II. This appears to indicate that inflammation would be more intense in Group II when compared to Group I. It was also seen at the baseline that the amount of CRP was greater in Group II from that of Group I, which may have been attributed to the intensity of inflammation. Research by Yazdi et al.[13] revealed a decrease in CRP levels in hemodialysis patients following periodontal intervention at 2 months. The research project by Fang et al.[15] found that CRP levels lowered in hemodialysis patients after periodontal therapy compared to the hemodialysis patients who did not receive any periodontal therapy. CRP levels are among the strongest cardiac and all-cause mortality predictors in individuals with ESRD.[22] Since periodontal disease is curable, its treatment in hemodialysis patients could lead to a decrease in CRP measures as well as the related risk of atherosclerotic complications.

The percentage of serum iron with TIBC which is equivalent to the circulating iron is estimated as the TSAT.[23] Decreased saturation of transferrin causes lowered erythropoiesis that contributes significantly to anemia associated with chronic diseases.[24] In this analysis, TSAT at T2 was increased substantially in all three groups (P < 0.05) which was close to the findings of the research by Vilela et al.[7]

During inflammation, chronic illness, and liver disorders, an acute-phase reactant that gets intensified is serum ferritin.[25] This study showed that serum ferritin was substantially higher in Group I and II at T0 compared to Group III. Serum ferritin levels were elevated at T2 in Group I and II, whereas in Group III, serum ferritin reduced. A research performed by Chakraborty et al.[25] shows that serum ferritin decreased in systemically stable patients with CP after 3 months of NSPT, which was close to our study.

Albumin, which appears to be lower in inflammation, is often a negative acute-phase reactant.[26] Our analysis revealed that at T2 serum albumin level improved in Group I (not statistically significant) and decreased in Group II (not statistically significant), while the level was almost the same in Group III patients from T0 to T2. Analysis by Wehmeyer et al.[19] gave similar results which reported that intensive periodontal care was not correlated via a rise in serum albumin concentration at 3 and 6 months of follow-up.

Group I and III serum creatinine levels decreased, but in Group II, the levels increased from baseline to T2, although it was not statistically significant. GFR increased in Group I (not statistically significant) and III (statistically significant), while in Group II, it decreased without statistical significance [Table 6]. A study by Artese et al.[21] conducted in systemically stable CP patients and predialytic patients found a decrease in serum creatinine and a rise in GFR levels. Graziani et al.[20] reported that after NSPT, GFR increased in CP patients. Reduced inflammation and better function of the endothelium can be obtained following periodontal therapy which can cause an impact on the microcirculation of kidney also.

At baseline, all three groups reported lower Hb levels, which could be attributed to proinflammatory cytokines, which serve as mediators in resisting erythropoiesis from bone marrow.[25] Our research found that, while it was not statistically important, there was a rise in Hb levels at T2 in all three groups. In all the three groups at T2, a statistically significant reduction in ESR was also found. For inflammatory processes, ESR is regarded as an important parameter. The findings concerning Hb and ESR were also similar to that of Agarwal et al.[27] Postoperative improvement in ESR may be attributed to a decrease in periodontal inflammation and its markers.

Nonsurgical periodontal treatment can ameliorate the anemic status of CP patients and improve the hematological parameters in turn.

Ioannidou et al.[28] and de Freitas et al.[29] in a systematic review reported a reduction in systemic CRP following periodontal treatment in periodontitis patients. In a systematic review, Chambrone et al.[30] also presented evidence to support the positive relationship between periodontitis and CKD, as well as the positive impact of periodontal therapy on estimated GFR.

The present study had limitations because it was a single-center study with relatively less sample size and narrow follow-up period (3 months).

   Conclusion Top

In our study, we observed that the clinical parameters decreased with statistical significance in systemically healthy CP patients after SRP. In hemodialysis patients, a statistically significant reduction in PI and BOP alone was observed, while other clinical parameters such as GI, PPD, and CAL did not indicate statistically significant differences. CRP reduction was statistically significant at T2 in CKD patients undergoing hemodialysis patients less than a year and in systemically healthy periodontitis patients and TSAT also increased with statistically significant in all the three groups. Thus, we conclude that NSPT can contribute to improvement in acute-phase reactants like CRP and iron indices in systemically healthy CP patients and also in CKD patients undergoing hemodialysis. However, to validate our results, longitudinal studies with bigger sample size and broad follow-up time are required.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Loos BG, Craandijk J, Hoek FJ, Wertheim-van Dillen PM, van der Velden U. Elevation of systemic markers related to cardiovascular diseases in the peripheral blood of periodontitis patients. J Periodontol 2000;71:1528-34.  Back to cited text no. 1
De Rossi SS, Glick M. Dental considerations for the patient with renal disease receiving hemodialysis. J Am Dent Assoc 1996;127:211-9.  Back to cited text no. 2
Darby I. Non-surgical management of periodontal disease. Aust Dent J 2009;54 Suppl 1:S86-95.  Back to cited text no. 3
George AK, Janam P. The short-term effects of non-surgical periodontal therapy on the circulating levels of interleukin-6 and C-reactive protein in patients with chronic periodontitis. J Indian Soc Periodontol 2013;17:36-41.  Back to cited text no. 4
[PUBMED]  [Full text]  
Musalaiah SV, Anupama M, Nagasree M, Krishna Ch, Kumar A, Kumar PM. Evaluation of nonsurgical periodontal therapy in chronic periodontitis patients with anemia by estimating hematological parameters and high-sensitivity C-reactive protein levels. J Pharm Bioallied Sci 2014;6:S64-9.  Back to cited text no. 5
Kumar S, Shah S, Budhiraja S, Desai K, Shah C, Mehta D. The effect of periodontal treatment on C-reactive protein: A clinical study. J Nat Sci Biol Med 2013;4:379-82.  Back to cited text no. 6
Vilela EM, Bastos JA, Fernandes N, Ferreira AP, Chaoubah A, Bastos MG. Treatment of chronic periodontitis decreases serum prohepcidin levels in patients with chronic kidney disease. Clinics (Sao Paulo) 2011;66:657-62.  Back to cited text no. 7
Armitage GC. Periodontal diagnoses and classification of periodontal diseases. Periodontol 2000 2004;34:9-21.  Back to cited text no. 8
Loe H, Silness J. Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontol Scand 1963;21:533-51.  Back to cited text no. 9
Silness J, Loe H. Periodontal disease in pregnancy. II. Correlation between oral hygiene and periodontal condtion. Acta Odontol Scand 1964;22:121-35.  Back to cited text no. 10
Ainamo J, Bay I. Problems and proposals for recording gingivitis and plaque. Int Dent J 1975;25:229-35.  Back to cited text no. 11
Sharma P, Dietrich T, Ferro CJ, Cockwell P, Chapple IL. Association between periodontitis and mortality in stages 3-5 chronic kidney disease: NHANES III and linked mortality study. J Clin Periodontol 2016;43:104-13.  Back to cited text no. 12
Yazdi FK, Karimi N, Rasouli M, Roozbeh J. Effect of nonsurgical periodontal treatment on C-reactive protein levels in maintenance hemodialysis patients. Ren Fail 2013;35:711-7.  Back to cited text no. 13
Craig RG, Kotanko P, Kamer AR, Levin NW. Periodontal diseases – A modifiable source of systemic inflammation for the end-stage renal disease patient on haemodialysis therapy? Nephrol Dial Transplant 2007;22:312-5.  Back to cited text no. 14
Fang F, Wu B, Qu Q, Gao J, Yan W, Huang X, et al. The clinical response and systemic effects of non-surgical periodontal therapy in end-stage renal disease patients: A 6-month randomized controlled clinical trial. J Clin Periodontol 2015;42:537-46.  Back to cited text no. 15
Kim YJ, Moura LM, Caldas CP, Perozini C, Ruivo GF, Pallos D. Evaluation of periodontal condition and risk in patients with chronic kidney disease on hemodialysis. Einstein (Sao Paulo) 2017;15:173-7.  Back to cited text no. 16
Rahmati MA, Craig RG, Homel P, Kaysen GA, Levin NW. Serum markers of periodontal disease status and inflammation in hemodialysis patients. Am J Kidney Dis 2002;40:983-9.  Back to cited text no. 17
Siribamrungwong M, Yothasamutr K, Puangpanngam K. Periodontal treatment reduces chronic systemic inflammation in peritoneal dialysis patients. Ther Apher Dial 2014;18:305-8.  Back to cited text no. 18
Wehmeyer MM, Kshirsagar AV, Barros SP, Beck JD, Moss KL, Preisser JS, et al. A randomized controlled trial of intensive periodontal therapy on metabolic and inflammatory markers in patients With ESRD: Results of an exploratory study. Am J Kidney Dis 2013;61:450-8.  Back to cited text no. 19
Graziani F, Cei S, La Ferla F, Vano M, Gabriele M, Tonetti M. Effects of non-surgical periodontal therapy on the glomerular filtration rate of the kidney: An exploratory trial. J Clin Periodontol 2010;37:638-43.  Back to cited text no. 20
Artese HP, Sousa CO, Luiz RR, Sansone C, Torres MC. Effect of non-surgical periodontal treatment on chronic kidney disease patients. Braz Oral Res 2010;24:449-54.  Back to cited text no. 21
Yeun JY, Levine RA, Mantadilok V, Kaysen GA. C-reactive protein predicts all-cause and cardiovascular mortality in hemodialysis patients. Am J Kidney Dis 2000;35:469-76.  Back to cited text no. 22
Wish JB. Assessing iron status: Beyond serum ferritin and transferrin saturation. Clin J Am Soc Nephrol 2006;1 Suppl 1:S4-8.  Back to cited text no. 23
De Domenico I, Ward DM, Kaplan J. Hepcidin regulation: Ironing out the details. J Clin Invest 2007;117:1755-8.  Back to cited text no. 24
Chakraborty S, Tewari S, Sharma RK, Narula SC. Effect of non-surgical periodontal therapy on serum ferritin levels: An interventional study. J Periodontol 2014;85:688-96.  Back to cited text no. 25
Kaysen GA. Serum albumin concentration in dialysis patients: Why does it remain resistant to therapy? Kidney Int Suppl 2003;87:S92-8.  Back to cited text no. 26
Agarwal N, Kumar VS, Gujjari SA. Effect of periodontal therapy on haemoglobin and erythrocyte levels in chronic generalized periodontitis patients: An interventional study. J Indian Soc Periodontol 2009;13:6-11.  Back to cited text no. 27
[PUBMED]  [Full text]  
Ioannidou E, Malekzadeh T, Dongari-Bogtzoglou A. Effect of periodontal treatment on serum C-reactive protein levels: A systematic review and meta-analysis. J Periodontol 2006;77:1635-42.  Back to cited text no. 28
Freitas CO, Gomes-Filho IS, Naves RC, Nogueira Filho Gda R, Cruz SS, Santos CA, et al. Influence of periodontal therapy on C-reactive protein level: A systematic review and meta-analysis. J Appl Oral Sci 2012;20:1-8.  Back to cited text no. 29
Chambrone L, Foz AM, Guglielmetti MR, Pannuti CM, Artese HP, Feres M, et al. Periodontitis and chronic kidney disease: A systematic review of the association of diseases and the effect of periodontal treatment on estimated glomerular filtration rate. J Clin Periodontol 2013;40:443-56.  Back to cited text no. 30


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
    Materials and Me...
    Article Figures
    Article Tables

 Article Access Statistics
    PDF Downloaded180    
    Comments [Add]    

Recommend this journal