Bacterial plaque and calculus are considered as main etiologic agents in the initiation and progression of periodontal diseases.Retention of plaque close to the gingiva is hastened by formation of supragingival dental calculus.Gingivitis is initiated due to the enzymatic effects and toxins released by the pathogenic microorganisms of the plaque This leads to plaque induced gingivitis which eventually progress to Periodontitis. Therefore, deposition of calculus is considered to be only a secondary phenomenon. Thus, according to these concepts calculus is considered as a mere predisposing and retentive factor since it does not irritate gingiva directly. It is always covered by a layer of microbial plaque which contains pathogenic microorganisms; which is a primary irritant and primary etiologic factor.