January 2015 Supplement

Introduction Periodontology is one of the oldest dental specialties in the world that deals with the tooth-supporting soft tissues and alveolar bone in both healthy and diseased conditions. Periodontal disease usually consists of gingivitis and periodontitis (Armitage, 1999). It is arguably the most common disease in humans (Guinness World Records, 2001), partly due to the unique characteristics of the dento-gingival structure and the etiopathogenic nature of the disease (Socransky and Haffajee, 1997; Jin, 2008). Globally, gingivitis predominantly affects adolescents and adults, and advanced periodontitis occurs in 5 to 20% of adults in both developed and developing countries (Söder et al., 1994; Papapanou, 1996; Petersen et al., 2005; Jin et al., 2011; Kassebaum et al., 2014).