Why CO Still Matters After CR Mounting
Many clinicians focus on centric relation (CR) as the gold standard for occlusion-based therapy, especially when treating temporomandibular joint disorders (TMD). However, centric occlusion (CO)—the habitual closure where most patients chew, speak, and function—reveals its own set of occlusal challenges. Even after achieving a stable CR mounting and performing initial adjustments, discrepancies often reappear during CO closure due to neuromuscular memory, postural adaptation, or long-standing parafunctional patterns.
In this guide, we focus on occlusal contact correction in CO, exploring how to manage balancing contacts, cusp vs fossa strategy, and other nuances of functional cusp coordination. Our goal is to restore harmony between CR and CO without compromising structural stability or muscular comfort.
Step-by-Step Occlusal Contact Correction in CO
1. Initial Assessment in Habitual Closure
Begin by observing where the patient’s natural mandibular closure leads them. Have them gently close without guidance. Use 40-micron articulating paper to highlight initial contact zones. Habitual CO interferences often differ from CR-mounted articulations, especially in post-splint therapy cases.
2. Identify Functional vs Non-functional Cusps
Understanding which cusps should bear force is foundational. In the maxilla, the palatal cusps are functional; in the mandible, it’s the buccal cusps. Non-functional cusps are more vulnerable to lateral forces and should not be adjusted indiscriminately.
3. Mapping Fossa vs Cusp Interference
A stable occlusion favors axial loading—where a cusp tip rests within a fossa. When cusp tips hit opposing inclines (cusp-to-cusp contact), lateral vectors increase, leading to muscular overload and joint strain. Correction often involves slight reshaping of opposing inclines, not cusp tips, to redirect forces vertically.
4. Prioritize Bilateral Posterior Balancing
Patients function best with evenly distributed forces across both posterior quadrants. Adjustments should avoid flattening functional cusps unless absolutely necessary. Bilateral balancing promotes long-term periodontal stability and reduces the risk of trauma from occlusion (TFO).
5. Anterior Guidance Check
Anterior teeth should guide excursive movements—not habitual closure. Evaluate whether early incisal contact is deflecting posterior teeth from seating fully. If necessary, polish incisal edges or lengthen discluded molars to maintain smooth transition from CO to functional movements.
6. Polish, Recheck, Repeat
After each adjustment, reassess using articulating film and shimstock. Proper occlusal contact correction requires iterative fine-tuning. When possible, use digital occlusion systems (e.g., T-Scan) to quantify timing and force distribution.
Occlusal Correction Strategy Table
| Contact Type | Preferred Correction Zone | Notes |
|---|---|---|
| Premature incline | Adjust opposing incline | Preserve cusp tip if possible |
| High non-functional cusp | Flatten cusp tip | Reduces lateral force risk |
| Cusp-to-cusp hit | Redirect to fossa contact | Promotes axial loading |
| Anterior interference | Polish incisal edge | Prevents posterior open bite |
When Not to Adjust CO Contacts
It’s tempting to correct every CO interference immediately. However, not all contact discrepancies are pathological. For example, if a patient is mid-splint therapy or has unresolved myofascial tension, occlusal adjustments could obscure diagnostic signs or worsen symptoms. CO interference management must be contextual and timing-sensitive. Always stabilize musculature first.
Case Example: Fine-Tuning Posterior Occlusion Balancing
A 52-year-old female presented with left TMJ discomfort and parafunctional grinding habits. Post-splint therapy revealed habitual CO contact isolated on #26. Rather than adjusting the maxillary fossa, clinicians reshaped the opposing functional cusp inclines on #36 and #37. A 2-week follow-up confirmed improved posterior occlusion balancing, normalized range of motion, and cessation of discomfort during mastication.
External Reference
Series Overview
This blog series began with a clinical focus on temporomandibular joint (TMJ) disorders, covering foundational topics such as joint dislocation, muscle dysfunction, splint therapy, and CR-CO discrepancies. Parts 1 through 6 build the groundwork for diagnosing and managing TMD in a stepwise fashion. Starting in Part 7, the focus transitions into deeper anatomical and biomechanical analysis, including centric relation versus centric occlusion, occlusal adjustment strategies, and long-term mandibular stability.
If you’re new to the series, we recommend starting with Part 1: Understanding TMJ Dislocation for foundational concepts.
