Comparing periodontal disease in identical twins: a case report.

Previous investigators have shown that numerous environmental and genetic variables may contribute to the pathogenesis of periodontal disease. This case report presents clinical and laboratory findings of a set of Caucasian female identical twins. One patient presented clinically with mild gingivitis and no clinical or radiographic signs of periodontitis. The other exhibited gingivitis with localized, moderate-to-severe periodontitis. Neither patient reported a history of systemic conditions that might influence their periodontal health, and neither presented other known risk factors, such as tobacco use. The only apparent variable was related to their oral hygiene. The periodontally involved patient exhibited higher plaque scores than her twin in all clinical visits. Subgingival plaque cultures revealed the presence of Porphyromonas gingivalis and Bacteroides forsythus only in the diseased twin. Both patients had low colony counts of Prevotella intermedia and Eikenella corrodens, but only the healthy twin harbored small quantities of Fusobacterium nucleatum. This case report offers an opportunity to assess etiology of periodontitis in two genetically identical patients whose only obvious difference was their oral hygiene.