An implant is planned to replace a maxillary central incisor. To develop a natural emergence profile, where should the implant platform be positioned in the apico-coronal dimension?

Correct answer: C. Approximately 2–4 mm apical to the cemento-enamel junction of the adjacent teeth

• A. The incisal edge level is meaningless as a reference for platform depth and would place the implant entirely outside bone.
• B. Placing the platform level with the adjacent CEJs leaves no vertical space to develop the transition zone. The restoration must then widen too rapidly, giving a bulky, unnatural emergence and a visible metal or grey shadow at the margin.
• C. CORRECT. The implant platform is placed roughly 2–4 mm APICAL to the CEJ of the adjacent natural teeth — equivalently, about 3 mm apical to the planned facial free gingival margin. This subcrestal depth is what creates the vertical running room needed for the restoration to flare gradually from the narrow implant platform (typically 4–5 mm) out to the much wider cervical cross-section of a natural incisor. Without that depth the crown emerges abruptly, producing a ridge-lapped, overcontoured restoration and an unnatural gingival architecture.
• D. A platform coronal to the CEJ is far too shallow. The implant shoulder will be visible or nearly so, the crown will look short and squat, and there is no room to establish the transitional contour.

Note: Position an anterior implant in three dimensions, not one. APICO-CORONAL: about 3 mm apical to the planned facial gingival margin. BUCCO-PALATAL: roughly 2 mm palatal to the facial emergence point of the planned crown, leaving at least 2 mm of facial bone. MESIO-DISTAL: at least 1.5 mm from an adjacent natural tooth and 3 mm from an adjacent implant. Too shallow gives a bulky, grey-shadowed crown; too deep risks bone loss and creates a cement trap that is nearly impossible to clean.