Allograft Ridge Augmentation: 3D Analysis of CAD/CAM Custom Milled and Prefabricated Conventional Allogeneic Bone Blocks and Dental Implant Follow-up

To rehabilitate patients after the loss of their own teeth, dental implants are nowadays the therapy of choice if the indication is suitable. In order to successfully place implants in the patient's jaw, a sufficient supply of bone in vertical and horizontal dimensions is necessary. Human bone is generally always in the process of reconstruction and changes over time. If there is not enough substance left for rehabilitation with implants due to previous degradation of the alveolar bone, bone augmentation can be performed. For this purpose, mainly autogenous, xenogenic or allogenic bone material is used. Bone augmentation using allografts shows satisfactory results in clinical use and has advantages such as elimination of morbidity associated with autogenous bone graft harvesting. In addition to the use of conventional and prefabricated graft blocks, it is now possible to produce individual allogeneic bone blocks using computer-aided design based on the patient's radiological data. After this bone has been placed in the patient, it can be restored with implants after a healing phase of about 6 months. In order to make the treatment as predictable as possible, it is crucial to know how a bone augmentation changes over time and whether bone remodelling or resorption occurs. How allogeneic bone blocks behave with regard to their stability and treatment success has already been investigated in some studies, but to date there is no study that deals with the difference between prefabricated, conventional and individually manufactured CAD/CAM allogeneic bone blocks. By retrospectively analysing existing clinical data, the aim is to compare how the two methods, prefabricated bone blocks and CAD/CAM-fabricated bone blocks, perform during the healing phase. A virtual volume analysis method of 3D digital imaging data (cone beam computed tomography scans) will be performed, which allows not only linear punctual evaluation but also area and volumetric analysis. Furthermore, the in the grafts inserted dental implants will be examined in terms of survival rate, complication rate and marginal bone loss by evaluation of the available follow-up records of up to 12 years.