1. Field of the Invention
The present invention relates to artificial teeth, and more particularly pertains to improved artificial posterior teeth for use in cases where the patient is completely edentulous (without teeth) and especially in cases where the edentulous ridges have been extensively resorbed or have shrunk away.
2. Description of the Prior Art
A variety of methods, some of them drastic and involving surgery and implants, have been developed to try to make dentures possessing greater stability and retention. Such surgical and implant methods expose the patient to risk and high costs.
The posterior teeth that are presently being used in dentures are generally cusped and designed to be set up in what is called a balanced occlusion. This means that a very accurate bite or centric occlusion must be established in the production of the denture. In all cases, if there is any error in setting up these teeth or even a minor amount of ridge resorption after the dentures are inserted, cusp interference will set up lateral forces which will tend to dislodge the denture when lateral or protrusive excursions are made.
The other most common type of posterior teeth presently used in dentures are those with flat occlusal surfaces known as zero degree teeth. These teeth are set up in a flat plane and as soon as the wearer of dentures moves into lateral or protrusive excursions there is no balancing occlusion. In other words, the wearer loses contact of many opposing posterior teeth and destabilizing forces are the probable outcome.