title: Estimation of volume density of interdental papilla components in patients with chronic periodontitis and interleukin-6 (-174G/C) gene polymorphisms.
abstract: BACKGROUND
  The association between interleukin-6 (IL-6) (-174G/C) gene polymorphisms and level of tissue breakdown and periodontal disease progression is unknown. The present study investigated quantitative parameters of interdental papilla in chronic periodontitis (CP) patients with IL-6 (-174G/C) gene polymorphisms.
  
  
  METHODS
  Sixty gingival samples were studied. After determination of IL-6 (-174G/C) gene polymorphisms using a tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) technique, 45 gingival tissue samples of CP patients (GG and GC+CC genotypes) were considered as case groups. Fifteen control samples were also collected from healthy individuals. After tissue processing, interdental gingival tissues were exhaustively sectioned into 4 μm-thick sections. Ten to thirteen sections were sampled by systematic uniform random sampling and stained with Masson trichrome, and the volume density (Vv) of the gingival components was estimated using Cavalier's point counting method. Statistical analysis was performed by Student t-test to compare differences between groups. The significance level was set at P < 0.05.
  
  
  RESULTS
  There were statistically significant differences in the Vv of epithelium, connective tissue, collagenous and non-collagenous matrix, and blood vessels between the control and CP groups (P < 0.0001). There were no statistically significant differences in the Vv of epithelium, connective tissue of gingiva, collagenous and non-collagenous matrix, and blood vessels among GG, GC, and CC genotypes in CP patients (P > 0.05).
  
  
  CONCLUSIONS
  Results of the current study showed that there was no association between IL-6 (-174G/C) gene polymorphisms and quantitative parameters of interdental papilla in CP patients.
authors.affiliation: Research Center for Infectious Diseases and Tropical Medicine, Iran; Department of Histology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Heidari
authors.affiliation: Research Center for Infectious Diseases and Tropical Medicine, Iran; Department of Histology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Mahmoudzadeh-Sagheb
authors.affiliation: Cellular and Molecular Research Center, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences and Health Services, Zahedan, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hashemi
authors.affiliation: Department of Periodontology, School of Dentistry, Zahedan University of Medical Sciences, Zahedan, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Ansarimoghaddam
authors.affiliation: Department of Histology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
authors.forename: Nadia
authors.initials: N
authors.lastname: Sheibak
keywords: Chronic periodontitis; genes; gingiva; interleukin-6; polymorphism