Periodontal disease is a complex biological process related to the interaction between groups of  microorganisms and the host immune/inflammatory response. The periodontal  tissue destruction is driven by  oral microbial flora that colonize the subgingival area  and  causes local and systemic diseases. Immune responses  gets activated on stimulation by bacteria or their products present in the dental biofilm and eventually play a major role in the alveolar bone breakdown observed in periodontitis.Sclerostin (SOST) is a secreted glycoprotein and an important regulator of WNT  (Wingless-related integration site) signaling in bone metabolism.The regulation of bone metabolism is a complex process of different signal transduction pathways depending on several local and systemic factors including cytokines, chemokines, hormones, and  biochemical stimulation.SOST is primarily expressed by osteocytes and binds to lipoprotein receptor‐related protein (LRP) 5/6 on the osteoblasts. Its expression is regulated by cytokines, mechanosensors and endocrine factors.Sclerostin deficiency leads to sclerosteosis and Van Buchem disease, characterized by progressive bone thickening due to increased bone formation.Inflammatory osteoclastogenesis mediated by pro-inflammatory mediators characterizes the central pathologic process of periodontitis.ICTP, a 12–20kDa fragment of type I collagen of bone, is released after bone resorption or collagen matrix degradation.Following procollagen synthesis and its release into the maturing extracellular matrix, collagen fibrils undergo post-translational modification resulting in cross-links between the telopeptide regions of type I collagen chains by lysyl oxidase.These cross-links are essential for providing mechanical stability to the maturing matrix and are specific to bone and cartilage and are not found in soft tissues such as skin where the cross-link is initiated by histidine residues.Elevated ICTP during bone resorptive events has also been found to coincide with the resorption rate as measured by histomorphometry and calcium kinetics.ICTP has recently been shown to highly correlate with high/low bone turnover diseases (myxedema, thyrotoxicosis, and primary hyperparathyroidism) as well as post-menopausal osteoporosis.ICTP correlated strongly with radiographic bone level and pocket depth and was significantly higher at periodontitis sites compared to non periodontitis sites.Hence the aim of the present study is to evaluate the levels of Sclerostin and C- telopeptide pyridinoline cross links (ICTP) in GCF and serum of gingivitis and stage II to stage III periodontitis patients.