Phenytoin-induced gingival overgrowth: a community-based cross-sectional study in Ferrara, Italy.

A community-based cross-sectional study was carried out in Ferrara, Northern Italy, to verify the frequency of gingival overgrowth in chronic phenytoin (PHT) users and the risk factors associated with its development. All subjects taking phenytoin were identified using the computerized list of drug prescriptions available in the study area. Most of the subjects were interviewed and underwent an oral examination to evaluate their periodontal condition. The prevalence of gingival enlargement in chronic PHT users was about 40%. In our study, sex, age age at onset of therapy, treatment duration, and oral hygiene were not significantly associated with the risk of developing gingival overgrowth. A direct relationship with daily dose was found to be an independent risk factor. Younger age and poorer oral hygiene seemed to predispose to the severest level of gingival involvement. These results support data from experimental studies by suggesting that drug-induced gingival overgrowth is a dose-dependent side effect whose severity could be affected by local factors.