When does anterior guidance remain compatible?

01One frame, two questions

Imagine an articulator with mounted casts. The pin traces a smooth line in protrusion. Did anterior guidance leave the posterior surfaces free to participate throughout that movement? To answer, we need to know what happened posteriorly while the line was drawn. The shape of the line cannot supply that observation.

Mechanical Bonwill Closure identifies two condylar references and the pin–table relation as the primitive sources in the paper’s architecture. We can keep those references and ask how the constructed anterior surfaces guide a particular excursion. Constraint-Regulated Occlusal Regime (CROR) names the case in which active anterior guidance stays compatible with posterior participation as the system moves.

02What must hold together

G_a describes the effective anterior input. G_c describes the guidance compatible with the condylar constraints. The paper relates both to vertical response per unit horizontal travel; neither is simply an angle read from a dial. Its general compatibility condition is G_a ≤ G_c. An almost inactive anterior input can satisfy that inequality and still regulate very little.

For CROR, the anterior input is present and closely matches the condylar-compatible guidance from the compatible side. A second condition concerns the response: posterior participation remains possible without anyone having to hold the surfaces together. Separation is minimized in the account; this does not require uninterrupted bilateral tooth contact or an exactly zero gap at every instant.

Definition 21 combines these two requirements. Here Ψ_P expresses deviation from continuous posterior participation. The paper describes observable signs of deviation, including separation, interruption of the trace and increased resistance. It supplies no universal formula for combining them into a number.

Manuscript: §13, pp. 14–15; §15.1, Definitions 17–21, pp. 19–20.

03Which movement, under which variations?

An uneventful pass at one setting answers a narrower question than the definition poses. Specify the movement interval and which small changes of the anterior parameters are under consideration. The matching and posterior-response conditions must persist along that interval across the declared changes. A check at the end of an excursion can miss a loss of participation halfway through it.

The manuscript gives no numerical value for “small” or “approximately.” A bench test must state its resolution and tolerances. A finite series can support a claim about the settings tested; it cannot establish the result for every neighbouring setting. Nor does the definition say that repeated cycling drives an articulator towards CROR.

Manuscript: §11; §16.3.7, Definitions 42–46, p. 24.

04Three cases with different answers

Start with A and B at the nominal setting, then compare them over the full variation. They have the same anterior input. A separate quantity r, specified for each case, lets us test the posterior response without deducing it from that input. C asks the converse: does a quiet posterior response establish active anterior regulation?

The numbers and bounds belong to this dimensionless example. The response r illustrates the second test; it does not calculate Ψ_P for an instrument. A failure for B over the selected family identifies the limit of that claim. At the endpoint s = 1 and |d| = 0.02, the response reaches 4 × 1 × 0.02 = 0.08. On the smaller interval |d| ≤ 0.01, B would satisfy the response bound of 0.04 throughout, and its anterior input would still match.

05What would a bench test need to show?

Specify the mounting, condylar settings, loading and excursion. Record how the anterior and condylar-compatible responses will be estimated. Then vary one declared anterior parameter while keeping the other conditions fixed. Follow the pin and independently record posterior contact or separation along the same movement, with enough resolution to compare where changes occur.

Would the posterior surfaces still participate if the operator did not press them together? State how loading is applied, so that contact maintained by pressure is distinguishable from participation under the declared conditions. If all we have is a pin trace, the posterior evidence is incomplete. The Re-audit’s distinction between admissibility and realization explains why. This is a proposed reading of a test, not a result for a particular articulator.

06Which CROR is meant here?

This study follows Constraint Compatibility: CROR means Constraint-Regulated Occlusal Regime. A separate draft catalogued as Future paper uses Controlled Regime Occlusal Realization (§1.3, pp. 6–9). Its construction is not imported into this definition. Here the term describes a mechanical regime; it does not prescribe an occlusal scheme.

07Original work and reading guide

Panagiotis Salikopoulos, Constraint Compatibility, Mechanical Bonwill Closure, and Anterior-Induced Regime Transitions in Mechanical Articulator Systems. Original work in the catalogue.

Read §§8–11 (pp. 10–13) for anterior input and boundary response; §13 (pp. 14–15) for posterior participation without enforcement; §15.1 (Definitions 17–22, pp. 19–20) and §16.3.7 (Definitions 42–46, p. 24) for the operational conditions. §§17–19 (pp. 28–31) give the qualitative accounts and their limits. The three-case comparison and bench question are additions to this site study, dated 7 November 2026.