Functional Neutral-Guide Behavior in Anatomical Incisal Tables of Fixed-Condyle Articulators

This manuscript presents a geometric decoding of anatomical incisal table behavior in fixed-condyle articulators. Using a reference instrument with a fully expressed anatomical incisal table, the study demonstrates that guidance behavior is not fixed but position-sensitive, governed exclusively by incisal table geometry rather than by condylar adjustability. Bench-level analysis identifies a continuous steepness gradient across the anatomical table, distinguishing between a Manual Zero (visual centering reference) and a True Functional Zero (elimination of vertical vector transmission). The work shows that steep, transitional, near-neutral, and fully neutral guidance behaviors can be produced within the same fixed system solely through controlled positional modulation of the incisal pin. The reference instrument is used strictly as a mechanical decoder and not as the subject of evaluation. The findings are geometry-governed and applicable to fixed-condyle articulators employing anatomical incisal guidance, independent of proprietary design features. This work functions as a standalone mechanical study and as a foundational component of the Articulators: Mechanical Behaviour and Geometrical Understanding corpus, providing a reproducible framework for interpreting articulators as constraint-driven systems rather than as parameter-based devices.