Inflammatory infiltrate, microvessel density, vascular endothelial growth factor, nitric oxide synthase, and proliferative activity in soft tissues below intraorally welded titanium bars.

BACKGROUND The aim of the present study is a comparative evaluation of inflammatory infiltrate, microvessel density, vascular endothelial growth factor, nitric oxide synthase, and proliferative activity in soft tissues below intraorally welded titanium bars. METHODS Twenty-two patients participated in this study. All patients carried immediately loaded one-stage titanium implants splinted with intraorally welded titanium bars. Each patient underwent two gingival biopsies, a control biopsy harvested from an area of mucosa 5 mm away from the titanium bar and a test biopsy from the mucosa below the titanium bar, which were histologically and immunohistochemically processed. RESULTS No fractures or radiographically detectable alterations of the welded frameworks were present. In all the cases examined, the average of the modified plaque index was 1, no suppuration or bleeding on probing was present, and probing depth was < or =3 mm. However, the immunohistochemical analysis revealed some differences. The inflammatory infiltrate was mostly present in test sites and its extension was much larger than in control sites. Statistically significant differences were found in microvessel density and Ki-67 expression among control and test groups (P <0.0001). The high intensity of vascular endothelial growth factor, nitric oxide synthase 1, and nitric oxide synthase 3 expression were mainly detected in the test group, whereas the low intensities were mostly expressed in controls, with statistically significant differences (P <0.0001). CONCLUSIONS In the present study, the immunohistochemical analysis shows that the tissues below the titanium bars underwent a higher rate of inflammatory and reparative processes. However, further long-term studies, where clinical and immunohistochemical data are collected in parallel, should be conducted for a better understanding of the expression pattern of inflammation markers.