Midline

The midline refers to the vertical contact interface between the two upper central incisors. Ideally it should be perpendicular to the horizontal plane formed by the front 6 teeth and parallel to the midline of the face. Minor discrepancies between facial and dental midlines are acceptable and in many instances not noticeable. Various anatomical landmarks (midline of the nose, forehead, chin and philtrum).

The philtrum of the lip is one of the most accurate of these anatomical guideposts. It is always the center of the face except in surgical, accident, or cleft cases. A line drawn vertically through the center of the filtrum should bisect the papilla (scalloped tissue between the centrals ) and align with the contact area of the two centrals.

If the philtrum and the papilla match but the midline of the teeth is incorrect, then the problem is usually axial inclination.

If the philtrum and papilla don’t match along a vertical line, then the problem is a true midline deviation.

A midline discrepancy can many times be corrected or made to appear more ideal by re-contouring the papilla with a laser and the teeth made to appear shifted over that amount by preparing the teeth differently under veneers. Any large discrepancies need to have the teeth orthodontically moved to correct it.