Clinical and experimental studies show, with few exceptions, that type 1 diabetes mellitus is associated with a delay in bone repair around endosseous implants. The effect of insulin in bone repair/remodeling is not completely understood. The aim of this study was to investigate the course of histological and ultrastructural changes of the osseointegration process under the influence of insulin. Titanium implants were inserted into the tibiae of male Wistar rats. Animals were divided into three groups: 1) rats with alloxan-induced diabetes; 2) diabetic rats treated with isophane insulin (2 IU/day); and 3) matching controls. Histological and histomorphometric analysis of bone-implant sections were performed 10 and 21 days after implant placement. Relative to control values, rats with alloxan-induced diabetes exhibited a 50% reduction in the area of formed bone (P < 0.001) and in the surface of contact between bone and implant (P < 0.01) 21 days after implant placement. There were no significant differences between groups 10 days after surgery. Values returned to normal levels in diabetic rats after insulin treatment. Presence of chondrocytelike cells surrounded by a cartilaginouslike matrix in diabetic rats suggests a delay in the process of bone repair. Ultrastructural characteristics of bone-implant interface in diabetic rats treated with insulin resembled those observed in controls. The data presented suggest that bone repair around endosseous implants is regulated, at least in part, by insulin. The results imply that the control of the metabolic status of the diabetic patient is essential for a successful osseointegration.

The mechanical properties of Ti alloys are changed significantly with the addition of interstitial elements, such as oxygen. Because oxygen is a strong stabilizer of the α phase and has an effect on hardening in a solid solution, it has aroused great interest in the biomedical area. In this paper, Ti-Zr alloys were subjected to a doping process with small amounts of oxygen. The influence of interstitial oxygen in the structure, microstructure and some selected mechanical properties of interest for use as biomaterial and biocompatibility of the alloys were analyzed. The results showed that in the range of 0.02 wt% to 0.04 wt%, oxygen has no influence on the structure, microstructure or biocompatibility of the studied alloys, but causes hardening of the alloys, increasing the values of the microhardness and causing variation in the elasticity modulus values.