Ridge augmentation / reconstruction
The placement of dental implants in a prosthetically driven position requires a certain width and height of the alveolar ridge in order to achieve an optimal aesthetic outcome. However, often, the bone is of insufficient quantity, which necessitates the augmentation of missing bone volume in horizontal and/or vertical dimensions.
Depending on the extend of the bone loss and location of the bone defect (maxilla, mandible, posterior or anterior), different techniques can be chosen for ridge reconstruction. Specifically, severe atrophic alveolar ridges with a pronounced vertical deficiency are commonly treated by block grafting (standardized and customized bone blocks), ridge splitting or bone expansion techniques (distraction osteogenesis). For the treatment of less severe horizontal bone defects with a minor vertical component, Guided Bone Regeneration (GBR) has become a well-established therapeutic approach.
Vertical and combined horizontal/vertical bone defects
Despite their known drawbacks such as increased patient morbidity and limited availability, autologous bone transplants are considered the ‘gold standard’ for the treatment of severe horizontal and vertical bone defects, as they provide the highest biological potential. However, allografts (maxgraft®) provided as blocks, plates, rings or even particulate material, in many cases provide a safe alternative for the treatment of such challenging bone defects.
Horizontal bone defects
Horizontal defects, in particular defects inside the ridge contour, can predictably be treated with many kind of bone substitute materials such as bovine bone grafts (e.g. cerabone®), allografts (e.g. maxgraft®) or synthetics (e.g. maxresorb®), within the scope of GBR. Barrier membranes with different mechanical- as well as resorption properties are used, depending on the dimensions of the bone defect. For extended horizontal bone defects a long lasting barrier membrane such as Jason® membrane optimally support the osseous regenerative process. Form-stable membranes like PTFE-membranes (e.g. permamem®) or titanium-reinforced variants thereof provide additional stability for augmentation of defects outside the bony envelope.
Innovative treatment concepts: Shell technique and bone ring technique
One option for the treatment of three-dimensional bone defects is the use of cortical plates harvested form the ramus according to the ‘Khoury technique’. The concept is based on the preparation of a biological container creating the necessary space for the stabilization and full incorporation of the particulate bone graft material. To eliminate a second surgical site for bone harvesting, allogenic bone plates (maxgraft® cortico) can be used as a substitute for autologous bone.
The bone ring technique enables localized horizontal/vertical bone augmentation and implant placement in one step, thus reducing the treatment time compared to conventional bone block augmentation with later implantation. The use of allogenic bone rings (maxgraft® bonering) has become an established and reliable alternative to autogenous bone ring harvesting, which avoids donor-site morbidity and limitations in quantity.