INTRODUCTION. Orthodontic teeth movement is accompanied by remodeling of alveolar bone, including the interradicular septum and periodontal ligaments (PDL). Periodontal signaling molecules have important functions during tooth movement and they are active in the bone remodeling process. Patients involved in orthodontic treatment belong to different age groups: therefore age must be considered as a contributing factor compromising the remodeling potential of periodontal tissues. The aim of the current study was to investigate the specific expression of signaling molecules in the PDL of interradicular septum in patients from different groups of age. MATERIALS AND METHODS. The study group included 25 patients to whom extractions of teeth was recommended as a part of further orthodontic treatment. 25 patients (10 males and 15 females) were divided into three groups as follows: 1) 12-14 years old; 2) 15-22 years old; and 3) 23 years old or older. The routine histological method was followed and samples were stained with hematoxyline-eosine. According to literature data in current immunohistochemical study were included and examined expression of NGFR (nerve growth factor receptor), TGF-β (transforming growth factor β), bFGF (basic fibroblast growth factor), FGFR1 (fibroblast growth factor receptor), IL-1 (interleukin 1), IL-6 (interleukin 6), IL-8 (interleukin 8), MMP-1 (matrix metalloproteinase 1), MMP-2 (matrix metalloproteinase 2), MMP-8 (matrix metalloproteinase 8), MMP-9 (matrix metalloproteinase 9), MMP-13 (matrix metalloproteinase 13) in PDL of interradicular septum. The distribution of these factors was evaluated semi quantitatively. RESULTS. Expression levels of FGFR1, bFGF, MMP 8 and 9, and IL-6 in PDL of interradicular septum structure were determined in all samples. Decreases in the mean values of signaling factors relevant to age were statistically significant in bFGF. CONCLUSIONS. Analyzed data suggest that bFGF, FGFR, IL-6, MMP 8 and 9 were determined as signaling factors in PDL of interradicular septum. Mean expression level decrease with age of FGFR1, IL-6, MMP-8, MMP-9 was non- statistically significant. The mean expression level of bFGF decreased with age, and this decrease was statistically significant. In younger patients, signal molecule expression is higher because of increased PDL metabolic activity. Increased PDL metabolic activity is a reason for higher expression of signal molecule in younger patients. Activity of remodeling process of periodontal tissue decreases with the aging and expression of signaling molecule decreases in adults.