Evaluation of Vertical Bone Augmentation Using a Titanium Ring Retained in Simultaneous Implants With Early Exposure: A Pilot Study in Dogs

Abstract

To evaluate the performance of titanium rings retained in implants placed simultaneously for vertical bone augmentation with early exposure. Twenty-four bone level tapered dental implants were inserted in the premolar areas of the mandible with standardized, 3.5 mm deep, vertical bone defects in four beagle dogs, and titanium rings containing a mixture of autogenous bone chips and Bio-oss were retained in the implants for vertical bone augmentation. Three weeks after the operation, all titanium rings were exposed, one titanium ring from each mandible of each dog was removed, and the other titanium ring was left in place with daily flushing. After 2 months, the dogs were sacrificed, the height of vertical bone augmentation was measured, and bone samples containing the implants were harvested and analyzed. The median (minimum-maximum) bone augmentation height (BAH) was 2.46 (2.18-2.62) mm on the buccal side and 2.80 (2.66-3.02) mm on the lingual side in the removal group; however, the BAH was 0.64 (0.32-0.92) mm and 0.70 (0.22-1.22) mm in the holding group. The bone volume/total volume (BV/TV) of the increased bone was 80.07% (72.64%-87.89%) with micro-CT analysis in the removal group, ideal bone osseointegration formed, and new bone was observed in the hard tissue sections. Within its limitations, the use of titanium rings retained in implants was found to be a reliable alternative method for vertical bone augmentation, and removing titanium rings is better for bone augmentation when early exposure occurs.