What is the least number of mandibular implants that can provide retention and stability for an overdenture?

The minimum number of mandibular implants recommended for effective retention and stability of an overdenture is two. This is grounded in several clinical factors regarding the biomechanics of implant-supported overdentures.

Using two implants can provide a sufficient retentive force to stabilize the overdenture while allowing an effective distribution of occlusal forces. The two implants can be placed strategically in the anterior mandible, where bone density is generally better, to maximize their effectiveness in supporting the prosthesis.

Furthermore, having two implants facilitates a locator or bar system that can enhance retention, making it easier for the patient to remove and replace the overdenture while still maintaining a secure fit during function. It also helps to improve the overall satisfaction and function for the patient compared to having a single implant, which may not provide adequate support or stability.

Choosing more than two implants could indeed improve stability and retention but is not necessary for basic functional requirements. Therefore, while options for three or four implants provide increased stability, the question specifically seeks the least number required, making two the optimal choice.