Contrary to popular belief, often times, loss of all remaining mandibular teeth with restoration by a complete denture presents a challenge to the patient. Gravity does not overcome the action of the tongue or the floor of the mouth when speaking or eating. Thus, patients must use their cheek muscles to keep the denture from being displaced. Furthermore, food may accumulate underneath the denture, causing discomfort.
Implant placement is always driven by the desired restorative outcome. This basic tenent emphasizes the need for involvement on the part of the restorative dentist from the very outset. A number of factors influence what can be achieved, including anatomical limiitations, the patient's desires, etc. However, a general rule of thumb is with the greater the number of implants placed, the greater the stability realized.
Options for implant placement in the edentulous mandible to stabilize a lower denture include placement of as few as 2 implants or as many as 4 implants. When a denture is retained in this manner, it is referred to as an overdenture. This allows the overdenture to still be removed, but it is stabilized resulting in increased comfort during eating and greater security. This mode of treatment is by far the most economical resulting in a significant improvement in overdenture stabilization with as few as 2 implants placed.
Yet another, but more sophisticated option for restoration, is implant placement with the intention of tooth replacement via a hybrid prosthesis. A hybrid prosthesis is the melding of a fixed (crown and bridge) and removable (denture) prosthesis; however, and most importantly, it is fixed in place. 4 - 6 implants are required to support such a restorative option.