Prosthodontics & Occlusion · patient case question
Which mandibular movement most likely produced this contact?
Patient case: Occlusal analysis with articulating paper
Patient: Female, 41 years old
Chief Complaint: Referred for occlusal assessment before restorative treatment.
Background: Full dentate arches. No history of orthodontic treatment.
Current Findings: Articulating paper has been used to mark the maxillary arch through a range of mandibular movements. A single isolated blue mark is present on the LINGUAL cusp of tooth #4 (maxillary right first premolar), shown below.
Show answer and explanation
Correct answer: C. Left lateral excursion
- A. In right lateral excursion the right side is the WORKING side. Working contacts are normally distributed across buccal-cusp inclines and involve several teeth, not one isolated lingual cusp tip.
- B. Retrusive contacts occur near centric relation on distal inclines of mandibular cusps and mesial inclines of maxillary cusps, not as a solitary lingual cusp mark.
- C. Tooth #4 is on the patient's RIGHT. During a LEFT lateral excursion the right side becomes the NON-WORKING (balancing, mediotrusive) side. The classic non-working contact is between the maxillary LINGUAL cusp and the mandibular BUCCAL cusp — precisely the surface marked here. An isolated mark on a maxillary lingual cusp is the textbook signature of a mediotrusive interference.
- D. In protrusion the anterior teeth should disclude the posteriors entirely. A posterior protrusive contact would be a separate finding, and it would mark on mesial inclines rather than a lingual cusp tip.
Note: ⚑ This item is genuinely two-sided and the group should talk it through. Maxillary lingual cusps DO also contact on the working side, so a right lateral excursion is defensible. What tips it toward the balancing side is that the mark is ISOLATED and sits on the lingual cusp — the hallmark description of a non-working interference. Rule of thumb: maxillary lingual cusp meeting mandibular buccal cusp on the opposite excursion = mediotrusive interference.
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