Reinforcing structures proliferated around a titanium implant inserted into the femur of female rabbits, in a hole smaller than the screw core

Abstract

One of the basic conditions for the clinical success of osseo-integrated implants is implant stability (Albrektsson and Zarb, 1993). It comprises two components, the primary stability that should be ensured at the time of insertion and the secondary stability, which gradually replaces the primary stability. The primary stability is ensured by the direct contact between the implant surface and that of the bone walls of the insertion hole. Secondary stability begins with the first position of new bone on the implant surface. The aim of the present study was to verify the reinforcing structures proliferated around the titanium implant inserted into the femur of 5 adult female rabbits, in a groove smaller than the screw core diameter. The results suggested that inserting the titanium implant into a hole with a smaller diameter than the screw core produces excessive pressure on the bone, which is felt up to a distance from the bone-implant interface. Consequently, mechanical strength of the bone is decreasing and proliferating bone consolidation formations appears on both periosteum and endosteum areas. Additionally, it was observed that newly proliferated bone extends laterally from the interface to a great distance, causing thickening of the bone wall. The observed structures were represented by branched bone trabeculae and bony protrusions into the medullary cavity, together with bone reshuffling processes with the appearance of numerous osteons, most of which are present at the level of the wall opposite the insertion area.