Radiation‐induced oral mucositis and periodontitis – proposal for an inter‐relationship

Virtually all patients who receive head and neck radiotherapy develop some degree of oral mucositis. Severe oral mucositis may necessitate an interruption of the course of radiotherapy and thus can serve as a dose-limiting factor. Periodontitis is a host-driven inflammatory response to a pathogenic bacterial biofilm in the subgingival environment, resulting in the progressive destruction of the tissues that support the teeth, specifically the gingiva, periodontal ligament and alveolar bone. This disease affects more than 50% of the population. Considering that radiation-induced oral mucositis and periodontitis are both linked with continuing presence of systemic inflammation, they may be associated through a primed inflammatory response as proposed by the 'two-hit' model. Alternatively, both conditions may be correlated as they represent a dysregulation of the inflammatory response. To date, no studies have looked into the association between these conditions. This review considers the current evidence that provides a rationale for proposing a link between periodontitis and oral mucositis.