Background: The recent years has seen enormous research attempts in the study for genetic factors that may predispose individuals to periodontitis, as one of the most common chronic infectious disease in humans.

Objectives: The aim of the present study was to determine the breakdown of interdental gingiva tissues in chronic periodontitis patients with TGF-β1 (-509) C/T polymorphisms.

Patients and Methods: A total of 60 gingival samples, including 45 patient and 15 healthy subjects, were selected for this study. Following determination of TGF-β1 (-509) C/T gene polymorphism by Tetra primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR), the patients were divided to three subgroups according to their genotype (6 TT, 21 TC and 18 CC). After tissue processing, sectioning and staining, quantitative parameters were estimated by Cavalieri’s point-counting estimation.

Results: The Volume density (Vʋ) of epithelium, connective tissue, collagenous and non-collagenous matrix and blood vessels had statistically significant differences between the control and chronic periodontitis (CP) groups (P < 0.0001). Statistically significant differences in the Vʋ of collagenous matrix, non-collagenous compartment and blood vessels between TT, TC and CC groups were found (P < 0.0001). There were no statistically significant differences in the Vʋ of epithelium, connective tissue of gingiva and non-collagenous matrix between TT, TC and CC groups (P > 0.05).

Conclusions: The results of the present study showed that TGF-β1 (-509) C/T is strongly associated with quantitative parameters of connective tissue constituents of interdental papilla in CP patients.