The second premolars, particularly the lower one, are the teeth most affected by agenesis. The typical situation is a second deciduous molar still present in the absence of the permanent premolar beneath it.

The retained deciduous tooth

If stable and without root resorption, it can be kept for years and is a reasonable holding solution. Its long-term prognosis, however, must be monitored: over time it can undergo resorption or loss, and the moment of replacement should be planned, not endured.

The options on loss or extraction

Orthodontic space closure, where occlusion allows.
Single implant, once growth is complete. The premolar site often has adequate bone height but may show horizontal atrophy after loss of the deciduous tooth.
Planned retention of the deciduous tooth while it remains clinically sound.

Timing

The choice depends on the state of the deciduous tooth and on age. Planning ahead avoids an unmanaged loss, with bone resorption that complicates any later implant. When the site shows horizontal bone deficit, graft-free management is explored in the article dedicated to the MTM approach.

Agenesis of the second premolar: options and timing

The retained deciduous tooth

The options on loss or extraction

Timing

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