Restoring a Single Implant in a Patient With a High Smile Line and a History of Gingival Recession
A 45-year-old woman has a single implant at the maxillary left lateral incisor site (tooth 22), placed 6 months ago and now ready for restoration. The implant is bone-level, 3.5 × 10 mm, with a 2 mm buccal shoulder and a screw-retained provisional that has been in place for 3 months. The gingival margin is 0.5 mm apical to the contralateral lateral incisor, the papilla is 1 mm short of the contact point, and the smile line exposes 2 mm of gingiva. She has a history of treated recession on the adjacent canine and a thin biotype. She is a teacher and wants the crown 'perfect.' The implant platform is 3 mm apical to the free gingival margin, and the interocclusal space is 6 mm.
1. What are the prosthetic risks in this case, and how does the thin biotype and high smile line change your material and design choices?
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Risk inventory:
- Aesthetic risk is the dominant risk. High smile line (2 mm gingival display) + thin biotype + 0.5 mm margin discrepancy + 1 mm papilla deficiency means any metallic show-through, any labial contour error, or any recession will be visible.
- Biological risk: thin biotype around a bone-level implant with a 2 mm buccal shoulder is prone to further recession; the provisional has already been in place 3 months, so the tissue is mature but fragile.
- Mechanical risk: 6 mm interocclusal space is generous - enough for a screw-retained crown with a titanium base, but the abutment height must be sufficient to support the ceramic without a thin, fracture-prone wall.
Design decisions:
- Material: A zirconia or lithium disilicate crown on a titanium-base hybrid abutment avoids the gray show-through of a metal abutment in a thin biotype. Do not use a full-metal or PFM collar on the buccal.
- Retention: Screw-retained is preferred - it avoids submucosal cement (a documented cause of peri-implantitis) and is retrievable. If the angulation prevents a screw channel, use a custom zirconia abutment with a very careful cementation protocol (retrievable cement, no excess).
- Emergence profile: The provisional has shaped the tissue; the final crown must replicate that profile exactly. Take an impression with the provisional in place (or use a scan of the provisional) to capture the emergence contour.
- Contour: Slightly under-contoured buccally to avoid pressure on the thin gingiva; the contact point should be positioned to support the papilla as much as possible.
What to tell her: 'Perfect' is not achievable when 1 mm of papilla is missing and the margin is 0.5 mm off; set the expectation now, with photos, before the final impression.
2. How do you manage the 1 mm papilla deficiency and the 0.5 mm margin discrepancy? What are the limits of what a crown can do?
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What the crown can and cannot do:
- A crown can mask a small margin discrepancy by extending the buccal contour and using a slightly more apical margin, but it cannot regenerate papilla. The interdental papilla is supported by the bone and the contact point; if the contact-to-bone distance exceeds ~5 mm, the papilla will not fill regardless of the crown.
- Measure the contact-to-bone distance on the radiograph. If it is >5 mm, the 1 mm deficiency is structural and will not close with prosthetics alone.
Options:
- Prosthetic compensation (first-line): Design the crown with a slightly longer contact point and a subtle buccal contour to make the deficiency less visible; use a pink ceramic if the deficiency is at the margin. This is often enough in a 2 mm smile display.
- Soft-tissue graft (second-line): A connective tissue graft or a pouch procedure at second-stage can thicken the biotype and gain 0.5–1 mm of margin, but it will not reliably rebuild a papilla.
- Orthodontic extrusion of the adjacent tooth to move the contact point - rarely justified for 1 mm.
- Accept and document: In a thin biotype with a high smile line, the honest answer may be that the result will be good but not perfect, and the patient must decide before the final crown is made.
Sequencing: Do not make the final crown until the soft tissue has been stable for 3 months and the patient has seen a provisional try-in or a digital mock-up. If she cannot accept the predicted result, the time to discuss a graft is now, not after cementation.
3. She returns 2 years later with 1 mm of further recession and a visible gray line at the buccal margin. What is your differential, and what do you do?
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Differential diagnosis for the gray line + recession:
- Metal show-through from a titanium abutment or a metal collar in a thin biotype - most likely if a hybrid or metal abutment was used.
- Implant platform show-through - the 2 mm buccal shoulder is now visible because the tissue receded.
- Ceramic fracture or chipping exposing the abutment.
- Peri-implant bone loss with secondary soft-tissue recession - must be ruled out with probing and a radiograph.
- Cement or restorative excess driving inflammation and recession.
Work-up: Probing depths, BOP, radiograph compared with the 1-year film, and a photograph. If bone loss is present, treat as peri-implantitis first - do not just replace the crown.
Management:
- If the cause is purely aesthetic (metal show-through with stable bone), replace the crown with a full-zirconia or lithium-disilicate crown on a zirconia abutment and consider a connective tissue graft to thicken the buccal tissue before the new crown.
- If there is bone loss, address the peri-implantitis first; the recession is a symptom, not the disease.
- If the implant is labially positioned and the platform is exposed, a pink ceramic veneer or a soft-tissue graft may be the only non-surgical options; explantation is a last resort.
Prevention review: This is why the original plan should have specified a zirconia/titanium-base abutment, a screw-retained design, and a soft-tissue graft at the time of placement in a thin biotype with a high smile line. Document the 2-year outcome and the revised plan.