Provisional Crown for a Fractured Central Incisor
A 52-year-old patient fractures tooth #8 to the gingival third after a fall. Endodontic evaluation is scheduled, but the tooth needs a provisional crown for at least four weeks. Tooth #9 has a facial composite veneer; shade A2 was selected for #8 under daylight-corrected lighting. The preparation has a 0.8 mm facial chamfer and 1.5 mm incisal reduction. There is no active bleeding, but the gingival margin is 0.5 mm subgingival on the mesial. The patient wants a provisional that matches #9 and does not interfere with the endodontic access plan. You have bis-acryl provisional material, autopolymerizing acrylic, a silicone putty matrix made before preparation, and a clear matrix. The dentist plans to open access through the lingual of the provisional if needed.
1. Which provisional technique and material would you choose, considering the esthetic demand, the subgingival margin, and the possible endodontic access? Explain your reasoning.
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I would use bis-acryl in the pre-preparation silicone putty matrix. Bis-acryl has low polymerization shrinkage, good esthetics, and enough strength for four weeks; the putty matrix reproduces the pre-operative contour and helps form the mesial contact. Because #9 has a composite veneer, I would isolate with a thin layer of separator or Teflon tape and avoid bonding the provisional to the veneer. I would trim the margins with a fine bur, check the mesial subgingival margin with an explorer, and polish. I would leave the lingual slightly thicker so the endodontist can open access without destroying the provisional, and I would plan to fill the access later with flowable composite. Bis-acryl is preferable to acrylic here because it produces less heat and shrinkage and better color stability, but it is more brittle, so occlusion must be checked carefully.
2. How would you check and adjust the provisional for occlusion and margin fit before cementation, and what would you do if the mesial margin is short by 0.5 mm?
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I would check centric and excursive contacts with 40-micron articulating paper and shimstock, adjusting the provisional so it is in light contact in centric and does not hold shimstock. I would check the margin with an explorer and a radiograph. If the mesial margin is short by 0.5 mm, I would not cement it as is, because an open margin will leak and may cause sensitivity. I would either reline the provisional with autopolymerizing acrylic or bis-acryl in that area, re-seat it on the prepared tooth, and re-trim, or remake it if the defect is large. A 0.5 mm short margin is too large for polishing alone; it needs addition or remake, followed by re-verification of fit and occlusion.