A proper and true periodontal diagnosis is essential in order to have rational treatment and preventive strategy and to identify sites at risk in periodontitis patients. Traditional clinical criteria are inadequate in determining the sites showing active tissue destruction, monitoring the response to therapy as well as to measure susceptibility to future periodontal break down. Recent immunocytochemically based approach has offered a new avenue in periodontal diagnostic research. The availability of complementary information on pathologically altered tissues has provided new diagnostic products to evaluate patient periodontal status as chair-side diagnostic tools. New technology is always exciting, however many products and devices are still under development. Their application to clinical situations is not yet fully understood. We must be certain that it provides practical information on treatment alternatives not currently available with existing methods in an efficient and cost effective manner.