The problems with lower dentures are so common that a popular dental school joke suggests you should charge $4,000 for upper dentures and do the lower one for free. Then when the patient complains about them, you can ask what they expect when they get it for free. The fact is, surveys show that 80% of dental patients are unhappy with lower dentures.
The opposite is true with implants, about 80% of dental patients with implants are happy with their lower prosthetic. The question with implants is how many are required for an overdenture of the jaw? The answer to this depends on the complaint. There are two main reasons patients give for not liking their lower dentures, either that they don’t stay in place, or they cause pain when biting or chewing.
The most frequent complaint with lower dentures is problems with movement during speaking or chewing. Fortunately, this is also the easier complaint to fix. This problem is caused by an insufficient bony ridge or lack of retentive seal due to the shape of the denture. Lower dentures are held in place by the tongue, so when the tongue moves, the denture moves with it. In this situation, one implant in each premolar area will in most cases be sufficient to hold the denture in place. Provided the implants are situated far enough apart and centrally placed between the anterior and posterior of the jaw, they will hold prevent the denture from tipping, which can cause the denture to lose its grip.
The second complaint, that of pain on biting or chewing, can be quite a bit more complicated. Discomfort is most commonly felt in the area of the premolars and is cause by the mental foramen. The mental foramen is a space in the jawbone that allows passage of the mental nerve and vessels. This nerve carries sensations from the front part of the lower jaw. Over time after the natural teeth are lost, the bone wears away and the nerve migrates until it sits directly under where the denture rests. As a result, the denture places pressure directly on the nerve anytime the patient bites, causing a sensation similar to that of hitting the funny bone.
The best solution by a long stretch are Implant Supported Dentures (click to continue reading about them).
