Implant-Guided Vertical Bone Augmentation Around Extra-Short Implants for the Management of Severe Bone Atrophy
The purpose of this study is to describe the conservative treatment of severe vertical bone atrophy by combining the insertion of extra-short implants and implant-guided bone augmentation. For that, a low-speed drilling protocol was selected to facilitate the collection of bone particles and to maintain graft osteogenic properties. Extra-short implants were incompletely inserted because of the severe atrophy, and the denuded implant surface was covered by autologous bone particles held together by the adhesive properties of plasma rich in growth factors. The surgical site was then covered with resorbable fibrin membrane, and the flap was repositioned and sutured. Eight patients with a mean residual bone height of 4.19 ± 0.97 mm were treated according to the described treatment protocol. The distance between the implant shoulder and the bony crest was 1.77 ± 0.18, 2.16 ± 0.23, and 1.97 ± 0.26 mm at the mesial, central, and distal aspects, respectively. Vertical bone augmentation resulted in the coverage of 85% of exposed surface by stimulating 1.6 ± 0.5 mm of supra-alveolar bone growth. All 10 extra-short implants placed were successfully osseointegrated. After a mean of 5 ± 1.6 months, provisional screw-retained prostheses were placed. Within the limitations of this study, we conclude that the minimally invasive approach described may successfully rehabilitate extreme vertical bone atrophy in the posterior mandible.
Figure 1. After the extra-short implants were inserted (a), the exposed implant surface was covered by the clot of plasma rich in growth factors containing autologous bone particles (b, c). Fibrin membrane was then placed to cover the surgical site before closure (d). Figure 2. Severe bone atrophy in the posterior mandible, where a residual height of 5.05 mm was available.
Figure 3. Anatomic position of extra-short implants inserted in severely atrophied posterior mandible. Figure 4. Exposed implant surface measured immediately after implant insertion at the mesial, central, and distal aspects. The lower and upper border of the box corresponds to the first and third quartiles, and the line inside the box is the median. The ends of the whiskers represent the lowest value within the 1.5 interquartile range of the lower quartile and the highest value within the 1.5 interquartile range of the upper quartile.
Figure 5. A radiograph (the same patient in Figure 1) showing the presence of residual bone height of 4.3 mm (a) that was treated by extra-short implant and vertical bone augmentation (b). At the second surgery, uneventful healing and no exposure of the implant could be observed (c), and the implant was covered by vertical bone augmentation (d). Figure 6. The denuded implant surface was covered by the clot of plasma rich in growth factors autologous bone particles. Five months after surgery, vertical bone augmentation was observed to cover the exposed implant threads and permitted the conservative rehabilitation of extreme atrophy.
Extra-short implants showing about 2 mm of implant surface that was covered by vertical bone augmentation (a, b). A periapical radiograph at the second surgery showing the absence of radiolucency at implant-bone interface (c).
Residual exposed implant surface measured at the time of the second surgery to connect the transepithelial abutment. The lower and upper border of the box corresponds to the first and third quartiles, and the line inside the box is the median. The ends of the whiskers represent the lowest value within the 1.5 interquartile range of the lower quartile and the highest value within the 1.5 interquartile range of the upper quartile.
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