INTRODUCTIONThe oral cavity holds great many secrets which are reflected purely in its appearance and function. Hence, very aptly the oral cavity is said to be the mirror of systemic diseases as many a systemic diseases can be identified on the basis of their oral manifestations alone. 2Diabetes mellitus is one such complex multifactorial genetic disorder of unknown etiology characterized by increased insulin secretion and decreased salivation.3 In addition to these the most common oral manifestation is the presence of periodontal disease, whose presence and severity can often lead the oral physician to suspect an underlying diabetes mellitus.This association of diabetes with periodontitis is attributed to the alterations in the permeability of the basement membrane, improper neutrophil chemotaxis, collagen synthesis, genetic predisposition and an increased susceptibility to periodontal pathogens. 2Salivary glands are important glands of the digestive system and serve functions which influence oral health in general.The salivary secretions are also very convenient for extirpation and collection. With an increase in investigator interest it is becoming apparent that many systemic diseases affect salivary gland function and/or composition potentiating its probable role as an indicator of the disease process.2 Also with the advent in sensitive immunochemical assays continuing, the compositional profile of human salivary secretions is expanding considerably, thus, establishing a range of normal values for a variety of intrinsic and extrinsic salivary components representing a stepping stone to use saliva as a diagnostic tool to assess oral health status. AIMS AND OBJECTIVES To assess the possible alterations in salivary compositionin patients with diabetes mellitus. 2. To assess presence and severity of periodontal disease in patients with diabetes mellitus. 3. To assess the possible role of saliva and its composition in initiation and progression of periodontal disease in diabetes mellitus. ABSTRACT Background and objectives:Neglected by dentists and ignored by physicians, saliva is the least appreciated of all body fluids. Yet, this secretion plays a vital role in the integrity of the oral tissues in the selection, ingestion and preparation of food for digestion and besides a whole lot of functions, in one's ability to communicate with one another. Saliva has proven to be a discriminating element in forensic sciences, an effective indicator of acute diseases of salivary glands and also a promising probe for drug monitoring. Because of multiplicity of functions served by saliva along with various physiologic processes involved, salivary secretions have long enjoyed a modest popularity as a research field. 1 With an increase in investigator interest, it is becoming apparent that many systemic diseases affect salivary gland function and/or composition potentiating its probable role as an indicator of systemic disease.