Periodontal disease is the most common inflammatory diseases with complex aetiology and multi-factorial in origin.The disease state ranges from gingivitis to periodontitis, affecting the supporting tissues of the teeth, leading to progressive destruction of connective tissue attachment and alveolar bone. In this book a study was conducted which reported that the salivary enzymes can be considered as the biochemical markers of the functional condition of periodontal tissues that provides new opportunities in making diagnosis and following the efficiency of curing periodontal disease.