The subgingival microflora in phenytoin-induced gingival hyperplasia

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: Craig Elice Date: 04/16/2010
Article title: The subgingival microflora in phenytoin-induced gingival hyperplasia
Author(s): Takada k, Sugiyama H. et al
Journal: J Periodont Res 38:477-81
Month, Year: 2003
Major topic: Bacterial flora of Phenytoin induced gingival hyperplasia
Type of Article: Research article
Purpose: This article evaluates the microflora of patients taking phenytoin and further studies the relationship between phenytoin induced gingival hyperplasia and the presence of black pigmented obligate anaerobic Gram negative rods.
Overview of method of research: Subgingival plaque samples were collected from 38 patients with phenytoin induced gingival hyperplasia, 7 patients with no gingival hyperplasia who received phenytoin as a control, and 37 patients with no history of phenytoin exposure as the blank sample. All 82 patients were between 16 and 35 years of age and were considered mentally challenged. Microbiological examination via selective media were used to determine levels of Strptococcus, veilonella, fusobacterium, actinomyces, and black pigmented obligate anaerobic Gram negative rods. Further identification of black-pigmented rods were conducted.
Results and Discussion: The data indicated that the incidence of black pigmented rods in the test group was significantly higher than those in the control or blank groups. Further evaluation identified the group of Prevotella intermedia to be the present in greatest amount in the test group. Phenytoin causes gingival hyperplasia in approximately 50% of patients taking the drug. Its mechanism of action is uncertain, but it has been suggested that phenytoin sensitive fibroblasts may be present. Phenytoin also effects the immune system by inducing lymphoid hyperplasia and lymphomas, as well as induces secondary drug immunodeficiency. It also causes a decreased sodium flux and cellular folic acid uptake. However, a bacterial inflammatory component is necessary for gingival hyperplasia to occur. In this study, phenytoin seemed to elevate the levels of black pigmented rods above the control and blank groups. In other studies it was also shown that phenytoin seemed to suppress streptococcus and actinomyces yet that was not the case in this study.
Conclusion: It was concluded that the bacterial flora was altered in subgingival plaque by phenytoin. Elevated levels of black pigmented rods, specifically Prevotella intermedia were found in these samples
Assessment of article: Good article, however, it did not show that Prevotella intermedia caused gingival hyperplasia, only that it was elevated in the experimental group.