The oral mucosa can suffer a series of traumatic injuries from various causes (bacterial plaque, tartar, fillings, incorrectly adapted prosthesis). A risk factor generating periodontal diseases is represented by fixed orthodontic therapy, if the forces exerted on it are excessive. These forces cause more or less extensive injuries both on the surface and in depth. One of these lesions is gingival hypergrowth. Early injuries concern only the superficial periodontium and are represented by mild or moderate inflammation, gingival hypergrowth, which can be reversible after removing the irritating factor (bacterial plaque, tartar). Advanced injuries are characterized by major clinical, radiological and tissue changes that cause the destruction of the deep periodontium (alveolar bone, deep ligament). Hypergrowth changes may occur at the epithelial level with reduced conjunctival reaction or may predominantly involve fibro-connective structures of the chorion with insignificant reaction in the epithelial component. Through this study, we highlight superficial and deep changes at the gingival and periodontal level.