Dealing with abutment design errors of an osseointegrated one-piece hybrid root-analogue implant in the esthetic zone

Background

Computer-aided design/Computer-aided manufacturing (CAD/CAM) milled root-analogue implant (RAI) systems can be a great alternative to conventional dental implants if the indication is appropriate. It has been shown that RAIs can reduce resorption processes of bone and soft tissue as a form of immediate implantation. However, such digital workflows can lead to errors resulting from intrinsic and extrinsic factors and can potentially increase with each transition in the digital workflow. Whilst the studies on RAIs have focused on osseointegration and implant success, to date, none of them have addressed the prosthetic abutment design of RAIs. Therefore, this case report highlights the importance of proper abutment design of a RAI and shows how to properly deal with an undersized prosthetic abutment in an already osseointegrated RAI, in the maxillary esthetic zone.

Case presentation

We report the case of a 34-year-old female patient who was implanted with a RAI in the maxillary esthetic zone. The tooth 11 was found to not be worthy of preservation and was carefully extracted. Afterwards, a CAD/CAM milled RAI was press-fit placed immediately. After the RAI had healed, the abutment was found to be prosthetically undersized. As a result, the implant could not be directly restored with a conventional crown, as the retention surface was too small to ensure a permanent hold. For this reason, the decision was made to incorporate a retention pin in the definitive crown, which engaged palatially in a retention groove by drilling into the abutment. Thus, a permanent fixation of the final prosthetic restoration was achieved.

Conclusions

Appropriate abutment design is crucial for the prosthetic treatment of the RAI, especially in the esthetic zone. In the future, the planning and development of RAIs should focus on the optimal abutment design and the sources of error within the planning and manufacturing process. Finally, the increasing outsourcing of steps within the prosthetic planning can lead to errors and should be taken with great caution.