Relationship between smoking and periodontal clinical findings and gene expression of IL-6 and TNF-α in severe periodontitis (clinical and laboratory data)

Abstract

The association between the periodontal conditions and smoking is attracting increasing attention. There is little information about the significance of the gene expression levels of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) for the severity of attachment loss in patients with smoking habits. The aim of this study was to evaluate the relationship between the severity of periodontitis and the gene expression levels of IL-6 and TNF-α in the presence of a main risk factor – smoking. A total of 20 individuals (periodontitis patients) participated in this study. The following clinical parameters were studied: hygiene index, gingival bleeding index, probing depth, clinical attachment loss, furcation involvement and tooth mobility, in patients of mean age of 50.25 ± 8.45 years with untreated periodontitis. Gingival biopsies were taken adjacent to shallow (<4 mm), moderate (4–6 mm) and deep (> 6 mm) periodontal pockets and similar attachment loss for Real-Time polymerase chain reaction (PCR) assessment of IL-6 and TNF-α gene expression levels. The obtained results demonstrated higher values for attachment loss and periodontal pocket depth in the presence of smoking. Furthermore, the results indicated smoking as an important risk factor which could greatly influence the studied gene expression levels. Smoking affected the gene expression mainly in conjunction with deep periodontal pockets. Our results suggest that smoking is an important risk factor for attachment loss in periodontitis patients demonstrated by clinical measurements and IL-6 and TNF-α gene expression.