Dentures of the upper jaw
In the upper jaw, the palate with its relatively large surface provides a good base for anchoring a prosthesis. If the bone level of the upper jaw is sufficient, usually not even anchoring elements such as implants or teeth are necessary to fix the prosthesis satisfactorily. The upper jaw prosthesis holds by a suction effect.
Due to its viscosity, the saliva produced acts as a lubricant between the acrylic base and the palate, thus creating a negative pressure which fixes the upper prosthesis. Therefore, it can often only be removed from the upper jaw with external force. However, if there is only a deficient bone level, which does not give the prosthesis a chance to hold, retaining elements are necessary to ensure that the prosthesis is sufficiently fixed.
Possibilities are offered by implants, mini-implants or, if still available, the own teeth. If there is not enough bone to anchor implants, bone can be transplanted externally with grafts to the desired location so that the implants can grow firmly. However, this procedure is associated with a high level of stress for the patient. Mini implants are a good alternative, which are associated with a moderate surgical load. They can also be implanted in cases where the bone level is low and provide a satisfactory hold of the prosthesis.
Dental prosthesis of the lower jaw
The denture has a much smaller area in the lower jaw to be fixed by the tongue. It is held only at the alveolar ridge. This fact is the reason why good hold in the lower jaw is very difficult to realize and depends strongly on the individual situation.
If implants, mini-implants or teeth are still present as holding elements, the prosthesis can be attached to them so that it is firmly fixed. As soon as the lower jaw is edentulous, the bone tends to recede, to atrophy. This makes it all the more difficult to produce a well-fitting prosthesis that the patient is satisfied with.
If the atrophy of the jaw is advanced, there is usually far too little bone to attach implants, unless bone is surgically created with grafts. This procedure is very costly and uncomfortable for the patient, so it discourages most of those affected. Therefore, the only alternative is the implantation of so-called mini-implants, which are much shorter than the conventional ones and thus allow a low jaw level. Once these artificial holding elements are in function, the jawbone no longer retracts because it is in use. Thus, a certain jaw level can be maintained by the mini-implants and creates a variant of fixation that is satisfactory for the majority of patients.
