Risk factors in phenytoin-induced gingival hyperplasia.

A survey was carried out into the degree of gingival hyperplasia in 68 patients receiving phenytoin in a hospital for the mentally handicapped. Comparisons of degree of gingival hyperplasia exhibited by the patients were made with a range of parameters by analysis of variance and Chi square tests. The severity of the hyperplasia increased with increasing dose, increasing dose per unit body weight and serum levels of phenytoin and also with decreasing age and weight of the patients. No significant relationship (P less than 0.2) was found between serum folate levels and degree of hyperplasia. Poor oral hygiene predisposed patients to hyperplasia.