Fig. 3

The apical region of a zygomatic implant can be in close proximity to the orbit (gold double line), the infratemporal fossa (not shown), or the apex of another zygomatic implant (red double line). When a 1–2 mm safety clearance for surgery is applied as in conventional dental implants, a 1 mm threshold of linear error from scan-body-assisted surface-based registration was deemed clinically relevant for this investigation.