Quantification of Image Artifacts from Navigation Markers in Dynamic Guided Implant Surgery and the Effect on Registration Performance in Different Clinical Scenarios

Purpose: Different navigation markers in dynamic guided implant surgery could cause different degrees of artifacts, which would affect the accuracy and efficiency of the implant navigation system. This study aimed to quantify artifacts caused by navigation markers made of different materials and to evaluate their effects on registration accuracy under various oral conditions. Materials and Methods: Four U-shaped tubes with different navigation markers (440c stainless steel, silicon nitride, zirconium oxide, and aluminum oxide) were produced by three-dimensional printing. Four kinds of maxillary plaster models were prepared to simulate four tooth crown conditions. U-shaped tubes combined with different tooth models were scanned using cone beam computed tomography. The size of artifacts from different navigation markers and registration rate were measured. Abrasion performance of navigation markers was evaluated by scanning electron microscopy images. Results: Aluminum oxide navigation markers showed the fewest artifacts. Silicon nitride markers caused fewer artifacts than zirconium oxide and 440c stainless steel ones (P .05) and had the best registration performance under all tooth crown conditions with the lowest volume of abrasion. Registration data suggested aluminum oxide worked badly under artificial crown and natural tooth conditions for its lower radiopacity, and zirconium oxide worked undesirably in edentulous conditions. 440c stainless steel was worst in all dental conditions. Conclusion: Navigation markers made of silicon nitride have the best overall performance and perform the best in registration under all circumstances owing to less artifact generation, better radiopacity, and desirable abrasion resistance. Silicon nitride can be regarded as an ideal material, including but not limited to oral implant navigator-guided surgery. Keywords: artifacts, cone beam computed tomography, dental implants, dynamic guided, navigation marker, registration