MEASUREMENTS OF STABILITY CHANGES OF TITANIUM IMPLANTS WITH EXPOSED THREADS SUBJECTED TO BARRIER MEMBRANE INDUCED BONE AUGMENTATION - AN EXPERIMENTAL-STUDY IN THE RABBIT TIBIA

The purpose of the present study was to evaluate in a rabbit model the changes in stability of implants that had been subjected to barrier m embrane induced bone augmentation, as compared to untreated controls. One titanium implant was inserted in each proximal tibial metaphysis o f 10 rabbits. The implants were placed in such a way that 4-5 threads on one side of the implant were left uncovered by bone. On the test si de, the exposed implant surface was treated by means of a barrier memb rane technique to provide for bone augmentation, while the contralater al side was untreated. The stability evaluations were made by means of resonance frequency measurements (RFM) at Day 0 and after 8, 16 and 2 4 weeks of healing. In addition, changes in the area of exposed implan t threads were documented and measured on photographs. Removal torque measurements were performed at the day of sacrifice. In this study it was not possible to demonstrate a statistically significant better sta bility of implants subjected to barrier induced bone augmentation as c ompared to control implants still having exposed threads as evaluated by RFM and removal torque measurements.