Restorative & Materials · single question
After placing mesial #20 and distal #21 composite restorations, bitewing radiograph shows an open contact and food impaction. What is the most likely cause?
Show answer and explanation
Correct answer: D. Poor contour and adaptation of the matrix band
Open interproximal contact after restoration = poor contour and adaptation of the matrix band during the restorative procedure. If the band is not properly burnished/adapted against the adjacent tooth and properly wedged, no adequate contact point forms → open contact → food impaction. Source confirms: 'Poor contour and adaptation of matrix.'
- A. Self-cleaning mechanism failure describes the RESULT (food trapping) — not the CAUSE of the open contact.
- B. Gingival contact point placement affects embrasure form but the question asks about the open contact specifically.
- C. Matrix band too thick would create TIGHT contact (hypercontact) when band is removed — not an open contact.
- D. CORRECT. Poor matrix contour and adaptation = inadequate contact point = open contact = food impaction.
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