Among the undesirable effects associated with the use of oral contraceptives are an increased incidence of thromboembolic events, an increased risk of myocardial infarction, and, in certain users, a significant elevation in blood pressure. An altered fibrinolytic activity may have a direct effect on the occurrence of localized osteitis, "dry sockets." It is also possible that gingival inflammation and loss of attachment may occur even under conditions of adequate plaque control. Salivary changes and alterations in the bony trabecular pattern of the mandible have been observed, but the clinical significance is as yet undetermined (Illustration).