The effect of titanium particles on the osseointegration

Dental implant surface treatments are being developed in order to increase roughness and consequently improve chemotaxis to optimize osseointegration. Despite the clinical success of dental implants, it is known that in many cases, marginal bone loss occurs in the peri-implant area and the mechanism related to this process is not clear in the literature. Some studies described that during implant insertion the peaks created to produce rougher surfaces, are prone to break and micro and nanoparticles of titanium are released in the peri-implant tissue culminating in an osteolytic process. The immune system reacts against the shed particles and the macrophages are the first cell linage interacting with titanium particles stimulating an inflammatory process that can overproduce cytokines, leading to bone resorption. In order to evaluate inflammatory response by macrophages, an in vitro study (Study 1) was developed culturing THP-1 cell linage in the presence of micro and nanoparticles of titanium in association with Lipopolysaccharide from Porphyromonas gengivalis (LPS PG) for 12h, 24 and 48h and pro-inflammatory cytokines related to the osteolytic process TNF-?, IL1-?, IL-6 were evaluated. Gene expression was analyzed using ??Cq method and Elisa comparing to the standard curve, the data were analyzed using ANOVA two-way and Tukey¿s test (p<0.05). As results it was observed that in the presence of micro and nanoparticles of titanium gene expression and protein production were increased compared to control, and the association of titanium particles and LPS PG did not increase gene expression and protein production compared to groups treated with titanium particles. Also to assess bone reaction in the presence of titanium microparticles an animal study (Study 2) was performed with 14 New Zealand White Rabbits, implants with turned surface were placed in tibia with 3mg of microparticles of titanium and femur using 1mg of microparticles of titanium in both legs of the animals. Data were analyzed using regression mixed model (p<0.05). After 7 and 28 days bone contact decreases in test group compared to control by histological and histomorphometric analysis. Moreover, 6 animals received 12 implants in tibia to evaluate the main osteogenic genes and after 7 days a decrease in the expression was observed. Conclusively the presence of titanium particles affects early stages of osseointegration (AU)