Cantilever FPD vs Implant in a Patient with a Short Clinical Crown and High Lip Line
A 45-year-old woman has a failing maxillary left first premolar (tooth 24) with a crack extending subgingivally on the palatal aspect. The adjacent canine (23) is intact and the second premolar (25) has a large existing composite. She has a high lip line and shows the gingival margin when smiling. Bone availability at 24 is 9 mm height and 5.5 mm width; the site is in the esthetic zone. She is a non-smoker, medically healthy, and wants 'the least number of crowns possible.' She is concerned about the appearance of her gums.
1. Compare a single implant crown, a cantilever FPD from the canine, and a three-unit FPD, and recommend one with reasoning tied to the esthetic and structural findings.
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Three-unit FPD (23–24–25): Rejected as first choice. It requires preparing an intact canine and a heavily restored premolar, removes sound tooth structure, and creates a hygienic challenge in a high-lip-line patient where the margins are visible. It also violates her stated preference for minimal crowns.
Cantilever FPD from the canine (23–24): Tempting because it uses one abutment, but a cantilever in the esthetic zone with a high lip line is risky - the pontic must be shaped to look like a premolar, and any buccal tissue change or metal show is highly visible. Cantilevers also load the canine off-axis. Not recommended here.
Single implant crown: Best option. 9 mm height and 5.5 mm width are adequate for a standard implant in the premolar region, though the buccal plate is thin (5.5 mm total width), so a slightly palatal implant position and possibly a connective tissue graft or contour graft should be planned to support the buccal gingival architecture. A screw-retained crown with a custom abutment allows retrievability and avoids a subgingival cement margin. The high lip line means the emergence profile and gingival contour must be carefully provisionalized.
Recommendation: single implant with staged soft-tissue development, screw-retained crown, and a provisional to verify esthetics before finalizing.
2. The crack extends subgingivally. What does this mean for the decision, and what would you do if the crack were 3 mm below the bone crest?
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A subgingival crack means the tooth cannot be predictably restored with a crown unless the fracture can be captured by a ferrule of ≥1.5–2 mm of sound tooth structure circumferentially. If the crack is shallow and the margin can be brought to within the sulcus with crown lengthening, the tooth may be salvageable - but in the esthetic zone, crown lengthening risks exposing the margin and creating an uneven gingival line.
If the crack were 3 mm below the bone crest: the tooth is not restorable. A ferrule cannot be achieved without significant osseous resection, which in the esthetic zone would produce a long clinical crown and an unacceptable gingival asymmetry in a high-lip-line patient. Extraction is indicated.
After extraction, the decision becomes timing: immediate implant placement is possible only if the buccal plate is intact and there is no active infection; otherwise, a staged approach with ridge preservation and delayed implant placement (3–4 months) is safer for esthetics. The implant plan then proceeds as above, with soft-tissue grafting to rebuild the buccal contour.