Implant born prosthetic rehabilitation of tumour patients can be difficult to perform. Challenges in treating such patients include disrupted anatomy with limited mouth opening due to previous ablative surgery as well as free-flaps or simple bone grafts, adjuvant therapy such as radiotherapy and, in general, poorer general health. Combining classical knowledge of ideal prosthesis placement and current virtual planning possibilities the positioning and in consequence the survival of dental implants can be optimised. Since prosthetic rehabilitation has a positive effect on the patients' quality of life and general health, we propose performing such surgeries as early as possible. All patients at our institution receiving pre-planned guided implant reconstruction and postoperative evaluation with Cone Beam Computed Tomography (CBCT) between 2015 and 2018 were evaluated for inclusion. Eight patients with a total of 30 implants met the inclusion criteria. The planned implant position was compared to the outcome position by fusing the two and deviations in entry-point position, apex-position, angular deviation and depth error were recorded. The mean (SD) discrepancy at entry-point was 2.28 (1.45) mm and 2.89 (1.53) mm at the apex, respectively. Mean (SD) angulation discrepancy was 9.5˚ (4.13˚) and the mean (SD) depth deviation was 1.52 (0.86) mm. Our results demonstrate the feasibility of pre-planned implant placement in challenging clinical situations and that only few concessions have to be made for precision.

The Surgical reconstruction of defects of the face is challenging. Local and regional flaps have an important part to play, but large defects of bone and soft tissue are a greater problem. Microvascular tissue transfer has become the standard for such patients, and preoperative planning of bony reconstructions is now common. To use these preplanning tools best the implants should be placed in the prosthetically ideal place, and the bone positioned to surround the implants – that is, truly backward planning of the position of the bone. The buccolingual angulation and the actual position of the implants during operation can be difficult to verify. Using commonly available software and 3-dimensional printing solutions, therefore, we have constructed an algorithm to optimise the position of these implants during the operation, and to get their position as close to the planned outcome as possible. This algorithm is adaptable to any implant system and is potentially possible in any implant or preplanning software unit.

Rehabilitation with implant-retained prostheses is a key step in the rehabilitation of patients after ablative head and neck surgery. Data of patients who underwent mandibular restoration with Astra Tech implants were gathered consecutively and analyzed retrospectively. Implant survival was calculated by Kaplan-Meier analysis, and Cox models were used to identify any association between implant failure and contributing factors. In total, 136 implants were placed in 33 patients. The main reason for ablative surgery was squamous cell carcinoma. Twenty-one patients received adjuvant radiotherapy with a cumulative radiation dose of 56-76 Gy prior to implantation. Failure occurred in six patients, resulting in the loss of 17 implants. The cumulative implant survival rate was 92.7% after 1 year and 87.5% after 20 months. Smoking and alcohol consumption were associated with a significantly higher implant failure rate. Most patients had a stable implant status after 20 months.