Advanced surgical navigation system using augmented reality technology
Akira Takebayashi, Toru Kano · Clinical Oral Implants Research · 2020
Background: Most current plate-type surgical navigation systems have the following problems: 1) The mouth opening at the operating area must be larger than the thickness of the plate and the length of the drill. 2) Irrigation with cool water is obstructed by the surgical plate, increasing the likelihood of bone burns. 3) In free end cases, the stability of the surgical plate is poor due to one-sided support. 4) In implant cases involving flap surgery, it is hard to use the surgical plate. Aim/Hypothesis: To solve these problems presented at the Background, we have developed an advanced surgical navigation system that indicates the 3D position of simulated implants in the patient's oral cavity using AR technology. Materials and Methods: The hardware components of our system are a web camera, a computer and a monitor. We use AR software and our original simulation software. The methods for using our system are as follows: 1) Make a 3D model of the patient from the CT data by volume-rendering. 2) Create a virtual mouthpiece in the AR space based on the shape of that 3D model. 3) Fit the virtual mouthpiece with the 3D model and place the 3D objects indicating the 3D position of simulated implants on the virtual mouthpiece. Then the 3D objects in the AR space move with the virtual mouthpiece. 4) Fit the virtual mouthpiece with the camera image of the patient's mouth and display the 3D objects in the oral cavity. Then the 3D objects displayed in the oral cavity work as surgical guides of drilling. Results: We tested our system on the patient's stone model and we carried out a drilling simulation on the training typodont. We also examined our system in the staff's mouth to make sure if it works in the actual oral cavity. Then we got the next Results 1) The 3D objects indicating the 3D position of simulated implants were displayed on the stone model with good stability and accuracy. 2) The 3D objects on the stone model can move in conjunction with the operation on the simulation software. 3) When there are alveolar bone or teeth together with the 3D objects, we can hide the overlapping areas. 4) The drilling simulation on the training typodont showed a good performance of our system. 5) The 3D objects were displayed in the staff's mouth proving that our system works in the actual oral cavity same as on the stone model. Conclusions and Clinical Implications: Our system has the following advantages compared with plate-type surgical navigation systems: 1) As our system has nothing to interfere with the operation in the oral cavity, all problems presented at the Background are solved. 2) Our system needs neither cost nor time for making the surgical plate. 3) At the planning stage, we can examine the 3D position of simulated implants from both anatomical and prosthodontic points of view simultaneously. Keywords: surgical navigation, surgical guide, AR technology, navigation system, guided surgery