Anatomy & Histology · patient case question
Where is the proximal contact located on the distal surfaces of teeth #8 and #9?
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: B. At the junction of the incisal and middle thirds
- A. The centre of the middle third is the typical contact location for POSTERIOR teeth, not maxillary centrals.
- B. CORRECT. On maxillary central incisors the distal contact sits at the junction of the INCISAL and MIDDLE thirds. The mesial contact of a central incisor is more incisal still — essentially at the incisal third.
- C. The junction of the middle and cervical thirds is far too apical for an anterior proximal contact and would leave a large open embrasure incisally.
- D. Contacts are never at the incisal edge itself; they sit slightly cervical to it.
Note: The general rule: proximal contacts move APICALLY (from incisal third toward middle third) as you move POSTERIORLY through the arch. Anterior teeth contact incisally, premolars and molars contact around the junction of the occlusal and middle thirds.
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