Virtual articulation using sequential mandibular intraoral scans and computational functional rotation reference...

Virtual articulators require accurate spatial orientation of digital casts for meaningful occlusal analysis during prosthesis design. Current methods for establishing this orientation rely on facial scanning, cone-beam computed tomography, electronic jaw tracking, or arbitrary population-based values. This proof-of-concept technique presents a computational method for determining a functional rotation reference from sequential mandibular intraoral scans captured at controlled opening increments using leaf gauges. The algorithm identifies regions exhibiting minimal translation during jaw opening through systematic grid search within anatomically defined boundaries posterior and superior to the molar positions. Points demonstrating negligible displacement while surrounding structures rotate lie geometrically on or near a rotation axis; a best fit line through their distribution establishes the functional rotation reference. This reference is then transformed to align with the intercondylar axis coordinates of the virtual articulator for digital cast mounting. Forward validation demonstrated root mean square deviations averaging 0.14 mm between simulated and actual scan positions. The technique was implemented for multiple virtual articulator systems including Denar Mark 330, Artex CR, and Stratos 300. This method enables patient-specific virtual articulation using only standard intraoral scanning equipment and leaf gauges, eliminating dependence on supplementary registration hardware.