Drug-induced gingival overgrowth. Drug-induced gingival overgrowth can be caused by phenytoin, cyclosporine, and a number of calcium channel blockers. There is evidence that genetic predisposition, length of treatment with the above medications, and poor dental hygiene all contribute to the evolution of this disorder.
Source: Prose NS, Kristal L. Weinberg's Color Atlas of Pediatric Dermatology, 5e; 2017.