The role of drugs in the pathogenesis of gingival overgrowth. A collective review of current concepts.

The gingiva and associated soft tissues of the periodontium may be enlarged in response to various interactions between the host and the environment. Although such enlargement usually represents an inflammatory response to bacterial plaque (91), increased susceptibility as a result of systemic factors or conditions should always be considered during the course of patient evaluation (139). Systemically related gingival enlargements include, but are not limited to, scurvy, leukemia, puberty, pregnancy, multi-system syndromes and selected drugs and/or agents (139, 182). In addition, fibrotic gingival enlargement has been reported and is believed to be the result of a genetic predisposition (such as hereditary or familial gingival enlargement); however, an idiopathic variant that has not been associated with genetic linkage or cause has also been described. Since the fibrotic gingival enlargements occur infrequently, minimal interest has been shown in the recent scientific literature, except for case reports and associated histological observations (138, 139, 182). Of the predisposing factors associated with disproportionate, disfiguring and functionally compromising overgrowth of gingival tissues, selected anticonvulsant drugs, calcium channel blockers and a potent immunosuppressant (cyclosporin A) have generated the most investigative attention in the scientific community. Unfortunately, the underlying pathogenic mechanism that mediates gingival overgrowth in affected individuals remains undefined despite intense clinical and laboratory investigation. The purpose of this chapter is to review gingival overgrowth and its association with anticonvulsant agents, calcium channel blockers and cyclosporin A. Discussion of the respective drugs and their association with gingival overgrowth will include pharmacokinetics, clinical manifestations, pathogenesis, histological characteristics and approaches to prevention and treatment based on current knowledge and investigative observations.