Restorative & Materials · patient case question
What is the principal advantage of a sectional matrix system over a circumferential band?
Patient case: Food impaction between two restored premolars
Patient: Adult who recently received Class II restorations
Chief complaint: “Food keeps getting stuck between my back teeth.”
Background: Mesial and distal restorations were recently placed in the premolar region.
Current findings: Bitewing radiograph shows an open contact between teeth #20 and #21.
Show answer and explanation
Correct answer: A. It reproduces a more anatomic proximal contour and a tighter contact
- A. CORRECT. A sectional matrix, used with a separating ring, is pre-contoured to the natural proximal anatomy and actively separates the teeth to compensate for band thickness. The result is a properly contoured contact at the correct height and a markedly lower incidence of open contacts than a flat circumferential band produces.
- B. A wedge is still required, to seal the gingival margin and aid separation.
- C. Speed is not the advantage, and sectional systems can take longer to place correctly.
- D. Cure depth is a property of the material and light, and is unrelated to the matrix.
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