3.4 Occlusion & Occlusal Assessment
Key Takeaways
- Intercuspal position is the position of maximum intercuspation of the teeth, whereas retruded contact position is determined by the condyles in their retruded axial position and is reproducible independently of the teeth
- Most restorative dentistry uses the conformative approach — restoring to the patient's existing intercuspal position; a reorganised approach starting from retruded contact position is reserved for extensive rehabilitation
- Static occlusal goals are even, simultaneous posterior contacts with lighter anterior contacts; dynamic goals are anterior or canine guidance that disoccludes the posterior teeth in excursion, with no non-working-side interferences
- Freeway space, the difference between resting vertical dimension and occlusal vertical dimension, is normally about 2 to 4 mm and is the check that a new denture or a raised occlusion has not overclosed or overopened the patient
- Shimstock foil about 8 micrometres thick is the practical test of whether a contact is holding; articulating paper marks show where teeth touch but not how hard
Last updated: August 2026
Why Occlusion Is Examined
Outcome C1.7 asks for an understanding of the principles of occlusion, and C2.5 asks for ideal occlusal goals — static and dynamic. Occlusion is examined because it explains restorative failure: a fractured cusp, a de-bonded resin-bonded bridge, a persistently sensitive new crown and a failing anterior composite build-up all have occlusal explanations.
Reference Positions and Terminology
| Term | Definition |
|---|---|
| Intercuspal position (ICP), also called centric occlusion | The position of maximum intercuspation of the teeth, irrespective of condylar position. Tooth-determined |
| Retruded contact position (RCP), also called centric relation contact | The first tooth contact made when the mandible closes with the condyles in their retruded, unstrained axial position. Joint-determined and reproducible even in an edentulous patient |
| RCP–ICP slide | The movement from first contact in RCP into ICP. Present in most people; a slide of about 1 mm or less that is straight and anterior is generally regarded as physiological |
| Occlusal vertical dimension (OVD) | Face height with the teeth in ICP |
| Resting vertical dimension (RVD) | Face height with the mandible at physiological rest |
| Freeway space (interocclusal rest space) | RVD minus OVD; normally about 2–4 mm |
| Working side | The side towards which the mandible moves in a lateral excursion |
| Non-working (balancing) side | The opposite side; contacts here are the most destructive interferences |
Static and Dynamic Occlusal Goals
Static (teeth together, ICP)
- Even, simultaneous contacts on the posterior teeth, directed along the long axes of the teeth.
- Lighter anterior contacts than posterior — classically anterior teeth hold shimstock only lightly, so that they are protected from the heavy vertical loads the posterior teeth are designed to accept.
- Stable stops — cusp-to-fossa or cusp-to-marginal-ridge contacts, not cusp-to-incline contacts, which generate lateral vectors and drift.
Dynamic (mandible moving)
- Anterior guidance — in protrusion, the anterior teeth contact and disocclude the posterior teeth.
- In lateral excursion, either canine guidance (the working-side canine alone disoccludes everything else) or group function (several working-side posterior teeth share the guidance). Both are acceptable; canine guidance distributes less load to the posterior teeth, group function spreads the load in a worn or periodontally reduced dentition.
- No non-working-side (balancing) interferences. A contact on the non-working side is loaded at an unfavourable angle and is a recognised contributor to cusp fracture, restoration failure and muscle pain.
- No interferences on the working side posterior to the guiding tooth.
Conformative Versus Reorganised
| Approach | What it means | When to use |
|---|---|---|
| Conformative | The restoration is made to fit the patient's existing ICP, adding no new contacts and removing none | The overwhelming majority of restorative dentistry, including single crowns, bridges and routine restorations, where the existing occlusion is stable and comfortable |
| Reorganised | The occlusion is rebuilt from retruded contact position, usually at an altered OVD, using a facebow record, a semi-adjustable articulator and often a stabilisation splint first | Extensive rehabilitation, severe generalised tooth wear, when the existing ICP is unstable or has been lost, or when the OVD must change |
Choosing the reorganised approach when the conformative approach would do commits the patient to far more tooth destruction and cost, and is a common examination trap.
Examining the Occlusion
- Look before you touch. Wear facets, fractured cusps, tooth mobility, migration, cheek and tongue ridging, masseter hypertrophy.
- ICP — ask the patient to close and identify the contacts; mark with articulating paper (a thin foil, ideally two colours: one for ICP and one for excursions).
- Shimstock — 8 micrometre metal foil. A contact that grips the foil is holding; articulating paper marks show where teeth touch, shimstock shows whether the contact is loaded. This is the key discriminator when checking a new restoration.
- RCP — guide the mandible with bimanual manipulation or a leaf gauge, identify the first contact, and record the direction and size of the slide into ICP.
- Excursions — protrusive and left and right lateral, recording the guiding teeth and any interferences, particularly non-working-side contacts.
- Records where needed — alginate or digital impressions for study casts, a facebow to relate the maxillary cast to the hinge axis, and an interocclusal record. Mounted casts allow occlusal analysis without the patient present and are essential before any reorganised approach.
Practical rule for a new crown: before preparation, record which teeth hold shimstock in ICP and which teeth guide in excursion. At fit, the same teeth should hold and guide. If the new crown is the only tooth holding shimstock, it is high, and the patient will return with sensitivity, a fractured restoration or muscle pain.
Occlusion and Pathology
- Primary occlusal trauma — excessive force on a tooth with normal support; reversible, no attachment loss.
- Secondary occlusal trauma — normal or excessive force on a tooth with reduced support; contributes to mobility and is a Stage IV complexity factor in the 2017 periodontal classification.
- Occlusal overload of implants — implants have no periodontal ligament and no proprioceptive buffer, so contacts are deliberately made lighter than on adjacent natural teeth, and lateral guidance is kept off implant-supported units where possible.
- Parafunction — bruxism and clenching amplify every occlusal problem. A stabilisation (Michigan-type) splint provides even contacts in RCP with canine guidance and protects teeth and restorations while the diagnosis is confirmed.
Test Your Knowledge
A newly cemented crown on a lower first molar is the only tooth in the arch that grips shimstock when the patient closes into their usual bite. What does this indicate?
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Test Your Knowledge
Which combination best describes ideal dynamic occlusal goals?
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Test Your Knowledge
A patient is being assessed for a new set of complete dentures. Resting vertical dimension is measured at 68 mm and the proposed occlusal vertical dimension at 66 mm. What does this indicate?
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Test Your Knowledge
When is a reorganised rather than a conformative occlusal approach indicated?
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