The Bone Core Technique for the Augmentation of Limited Bony Defects: Five-Year Prospective Study with a New Minimally Invasive Technique

The aim of this study was to evaluate a new minimally invasive surgical technique for the reconstruction of critical-size bony defect with local harvested bone core with simultaneous implant placement. In a prospective study, 186 consecutively treated patients were included and controlled clinically and radiologically for at least 5 years postoperative. Every patient presented a bony defect affecting the buccal, lingual, or palatal wall. In all cases, the alveolar crest was wide enough to allow implant placement inside the bony contours. During implant bed preparation, a trephine bur (3.5 mm external diameter and 2.5 mm internal diameter) was used to harvest a bone core from the socket. After implant insertion, the buccal/palatal/lingual bony defect was grafted with bone chips covered with the bone core stabilized through compression with microscrews. After 3 months of healing, the implants and the grafted bone were exposed and the width of the grafted area was measured. After prosthetic restoration, the patients were recalled regularly. A total of 223 grafted sites were documented. Minor primary healing complications were observed in 3 sites (1.4%), all in smoker patients, and were treated locally without any influence on the prognosis. All other sites healed uneventfully. In 19 cases (4.4%), exposure of the screw heads was detected 1 to 3 months postoperatively without any inflammation or consequences for the grafted bone. The average width of the reconstructed area at the end of the grafting procedure was 2.4 ± 0.8 mm, and at the reentry, 2.1 ± 0.6 mm. There was a difference of remodeling between bone cores grafted totally inside or partially outside the bony contours. Bone cores grafted completely inside the bony contours demonstrated no resorption at 3 months postoperative, while bone cores grafted partially outside the bony contours in most cases showed partial resorption of the bone outside the bony contours. After 3 months of healing, all 223 implants had achieved primary healing and osseointegration and were restored after an average time of 4 months. No implant failed during the control period. According to this study, the use of an autogenous bone core harvested during the implant bed preparation is a simple and safe method for the reconstruction of small bone defects.