This document discusses molecular mechanisms in gingival enlargement. It begins by providing background on normal gingival anatomy and histology. It then examines the role of the epithelial-mesenchymal transition process in inflammatory gingival hyperplasia and how this may serve as a source of fibroblasts. Finally, it explores fibroblasts collagen production and histological alterations in hereditary gingival fibromatosis, including how oxidative stress may be related to its pathogenesis.