Due to the incorrect positioning or alignment of implants, implant placement in non-augmented residual bone frequently leads to aesthetically unfavorable and problematic restorations.1
The objective of a GBR procedure, therefore, is the successful regeneration of bone in a defect area with high reliability and a low rate of complications.2 In the last decade, researchers and clinicians have focused increasingly on achieving success with a therapy that entails as few surgical procedures as possible, a low level of patient morbidity and a short healing period.
Space, time and rest are key
Large, three-dimensional defects continue to present a challenge in the world of everyday implant surgery. Conventional block augmentations are associated with patient morbidity. In addition, insufficient revascularization and bone block resorption during the initial course of healing, or long-term, can jeopardize treatment success.3 Alternatives to bone blocks have included non-resorbing membranes reinforced with titanium mesh.
The new titanium scaffold Yxoss CBR® is a good solution for bone defects that require improved regenerative potential and positional stability. The goal is to provide regeneration equivalent to autologous bone blocks but with better handling and reduced morbidity.
Yxoss CBR® – Customized Bone Regeneration
The Yxoss CBR® titanium scaffold is customized using a CAD/CAM procedure based on patient CBCT record and one advantage is that bone dimensions for subsequent implant placement can be pre-planned and achieved.
The titanium scaffold does not function as a membrane or barrier but simply as a stable basket or cage. Before placement in the bone defect, it is filled with a mixture of autologous bone chips, collected by SafeScraper®, and particulate bone replacement material (Geistlich Bio-Oss®). The combination provides both volume and regenerative capacity for the defect area.
Although the ideal ratio autologous bone to bone substitute is 1:1, good bone regeneration has also been observed with a ratio of 1:2 in our practice. Since the customized mesh does not have a barrier function, the use of a collagen membrane between the titanium mesh and mucoperiostal flap is critical (Fig. 1).
In the case of defects greater than two teeth, two layers of collagen membrane are used so as to achieve a sustained barrier function and protect the defect area from ingrowing soft tissue cells.
Stress-free primary wound-closure: To enable a stress-free primary wound closure after major volume augmentation, the periosteum must be separated from the underlying bone. The flap should also be mobilized lingually or palatally, as the three-dimensional titanium mesh encloses the alveolar ridge.
Primary wound closure is achieved with deep mattress sutures and single interrupted sutures.
Protecting the soft tissue: Should dehiscences at the wound margins occur, they should be de-epithelialized as far as possible and adapted with new sutures, or at least treated with chlorhexidine gel over an extended time frame. To prevent additional pressure necroses, we recommend in-situ dentures over the augmentation area to create adhesive bridges without mucosa-positioned, interim prosthesis.
Sufficient healing time: The healing period is approximately six months.4 With pronounced defects, a longer healing period of nine to twelve months might be necessary in order to achieve complete regeneration.
The surgical technique presented allows for predictable bone regeneration in patients with larger, three-dimensional bone defects. Compared to autologous bone blocks, treatment is less invasive, and the surgery time is shorter. Even in a complex, three-dimensional alveolar bone defect, the combination of autologous bone chips and bone replacement material generates a stable, augmented volume and, therefore, promises a more predictable outcome for patients. Overall, implants can be placed ideally for prosthetic restoration (“prosthetically- driven implant placement”).