Response of cortical bone to local controlled release of sodium fluoride: The effect of implant insertion site

Abstract

In a previous experiment, sodium fluoride in a biodegradable polymer matrix was introduced into the femoral canal of the rabbit and bone formation was compared with contralateral controls. We noted significant bone formation, but only in the distal third of the periosteal surface of the femur. This experiment was performed to distinguish fluoride-induced periosteal bone formation from that due to the reactive osteogenic changes associated with local injury caused by the process of implantation. A proximal approach on the right leg and a distal approach on the left were used for the insertion of the implants in rabbits. Femurs were removed after 30 days and tested for stiffness and load to failure. The cross-sectional area of mineralized bone was determined at proximal, midshaft, and distal locations. Fluorescent bone tissue growth labels were injected at weekly intervals to measure the rate of new periosteal bone formation. The results were compared with a control group that received sham implants. Results showed no difference between measured properties in right and left femurs in the control group or in those exposed to fluoride. A significant increase was found in the fluoride group in load to failure, along with cross-sectional area of mineralized bone, and periosteal growth rates compared with the control group, but no difference was seen in stiffness. No difference was detected between the response proximally and distally in the fluoride group regardless of the location of insertion. There were no detectable changes in serum fluoride level after implantation of the poly L-lactic acid/sodium fluoride matrix. These results show that fluoride exerts its osteogenic effects equally at proximal, midshaft, and distal regions of diaphyseal bone and is uninfluenced by the site of local injury due to insertion of the implant.

Titanium Implants after Alkali Heating Treatment with a [Zn(OH)4]2− Complex: Analysis of Interfacial Bond Strength Using Push‐Out Tests

“…The incorporation of trace essential elements into biomaterials has proven to be an effective way to stimulate bone formation. [3][4][5] Studies in vitro and in vivo have demonstrated that zinc (Zn) is able to stimulate bone formation and to inhibit bone resorption. [6][7][8] However, Zn must be released slowly from the implant surface because Zn at elevated levels induces adverse reactions.…”

Response of osteoblastic cells to titanium submitted to three different surface treatments

“…Surface modification aims to accelerate osseointegration and includes hydroxyapatite (HA) coatings, mechanical blasting (using either Al 2 O 3 or TiO 2 particles), anodic oxidation and acid-etching processes (different concentrations of H 2 SO 4 , HF, HNO 3 and HCl). Recently, some authors have reported on significantly improved bone tissue reactions by modification of surface oxide properties of titanium implants 1,19 or ion release 2 . Chemical modification of titanium implant surface is of particular interest because it may enhance osseointegration without embedding surface contaminants, such as grit particles 21 .…”

Bone healing at implants with a fluoride‐modified surface: an experimental study in dogs

“…Results reported from in vitro experiments indicate that fluoride ions influence formation of both organic and inorganic components of bone tissue. Thus, fluoride may increase the density of trabecular bone and enhance the incorporation of collagen into bone matrix as well as alkaline phosphatase activity (Shteyer et al 1977;Farley et al 1983;Andersson et al 1993).…”