Tooth decay and periodontal disease begin with plaque buildup. Plaque is an oral biofilm composed of microorganisms and a slimy matrix they produce. This biofilm adheres to the teeth and gums (Aruni 2015). Acidic byproducts of bacterial activity cause tooth decay and eventual formation of cavities (Edwards 2010; Mayo Clinic 2014a). An imbalance in the oral microbial community undermines healthy immunity throughout the body and triggers an inflammatory response in the structures that support the teeth. Over the long term, this causes local tissue destruction that can ultimately lead to tooth loss. Systemic inflammation driven by periodontal disease contributes to the link between poor oral health and whole-body health problems (Fernandez-Solari 2015; Hajishengallis 2015; Mayo Clinic 2014b).
According to the American Dental Association, the tooth surface may be considered sound (no decay), or have initial, moderate, or advanced decay (Young 2015). Root cavities are the most common type of dental cavity in older adults. They occur on tooth root surfaces that become exposed when the gums are inflamed or receding (Mayo Clinic 2014a; Bignozzi 2014; Edwards 2010; Gluzman 2013; Ritter 2010).
Periodontal disease is generally classified according to the degree of tissue involvement (Loesche 1996).
- Gingivitis, which is inflammation affecting primarily the gingiva (gums), is the milder form of periodontal disease. It is usually caused by plaque (Kawar 2011; Page 1986; Peedikayil 2015).
- Periodontitis is more serious than gingivitis because it affects the gums, periodontal ligament, and bone, can lead to tooth loss, and is associated with systemic diseases (Hajishengallis 2015). It can be chronic, characterized in part by slow to moderate progression, though periods of rapidly progressive tissue destruction may occur; or it can be aggressive, with rapid tissue destruction. In either case, periodontitis may be localized to a specific region of the mouth or may be widespread (Highfield 2009). Periodontitis is also associated with certain diseases (eg, diabetes) and medications (eg, some asthma medications, oral contraceptives) (Kawar 2011; Shashikiran 2007; Heasman 2014).
Large pockets of infection known as abscesses may arise as a result of periodontitis, and may be acute or chronic (Patel 2011). Necrotizing periodontal disease is a particularly severe form in which there may be sudden and rapid destruction of periodontal tissue (Highfield 2009; Herrera 2014).