Chronic hyperglycemia as a risk factor in implant therapy.

It has been estimated that by 2030, the number of patients with diabetes aged > 64 years will be > 82 million in underdeveloped countries, and > 48 million in developed countries. Chronic hyperglycemia delays wound healing by reducing the expression of growth factors in the wound fluid and re-epithelialization. Impaired wound healing in patients with diabetes has also been associated with inhibition of the production of stromal cell-derived factor-1alpha by several tissues including bone marrow, brain, heart, spleen, and gingivae. Chronic hyperglycemia interferes with the osseointegration of implants by deferring the expression of fibronectin and integrins. Results from experimental studies have shown a significantly higher bone-to-implant contact around implants placed in healthy animals compared with animals with streptozotocin-induced diabetes. Moreover, persistent hyperglycemia plays a role in abnormal differentiation of osteoclasts, thereby making bone tissue more susceptible to resorption. Furthermore, persistent hyperglycemia has also been associated with increased peri-implant soft tissue inflammation (increased peri-implant bleeding on probing and probing depth) and crestal bone loss. Clinical studies have shown that under optimal glycemic control dental implants can show success and survival rates of up to 100% in patients diagnosed with diabetes. Although patients with diabetes can undergo dental implant therapy and can exhibit implant survival similar to those in systemically healthy individuals, the contribution of glycemic control and regular oral hygiene maintenance cannot be disregarded.