Efeito de Diferentes Terapias no Reparo e na Microestrutura do Tecido Ósseo.

Abstract

The bone structure has a complex physiological process of regeneration, since this tissue has many particular characteristics in addition to undergoing continuous remodeling throughout life. However, there are acquired clinical conditions where bone repair process is compromised. Bone morphology and constitution are altered when associated with some specific use of medication or ionizing radiation, essential medical therapies for the treatment of some pathologies. Radiotherapy is currently used to control cancer, however, high doses of radiation cause metabolic damage to healthy tissues. In bone tissue, ionizing radiation promotes changes in its chemical and physical composition, resulting in immediate collapse of bone quality, producing serious effects such as mandibular osteoradionecrosis (ORN), increased risk of fractures and tissue hypovascularization, resulting in a reduced healing capacity. Osteoradionecrosis affects patients who receive ionizing radiation as therapeutic treatment for head and neck cancer. The affected area by radiotherapy has the process of restoring bone tissue impaired due to hypovascular, hypocellular and hypoxic tissue changes. The use of bisphosphonates is regularly indicated for conditions related to cancer and metabolic bone diseases, acting mainly in inhibiting osteoclastic activity and consequently inhibiting bone resorption. Jaw osteonecrosis related to the use of bisphosphonate is a common complication that adversely affects quality of life, producing significant morbidity in patients affected injuring the metabolism of bone repair. Hyperbaric oxygenation (OH) has been used as an efficient strategy to minimize the damage related to osteoradionecrosis and osteonecrosis associated with the use of bisphosphonates. In this context, the present phd dissertation proposed an study on the effect of OH on bone regeneration through systematic review and through experiments in rats submited to ionization and medication protocols. In conclusion, the analyzes indicated that OH favored the bone repair process once compromised, through beneficial effects such as: percentage of new bone formation, increased angiogenic response, as well as activities related to osteogenesis and bone remodeling.