What are Fremitus Teeth

Inclined plane

The inclined plane is a device that fully implements the principle of functional orthodontics. The force that triggers the remodeling process is only generated by clenching. This is a special acrylic device that is placed on the lower teeth and only touches individual teeth in the opposite jaw. The force when biting is distributed vectorially on the inclined plane, so that the tooth to be corrected is pressed in the labial direction. The corrective forces occur intermittently and only in an order of magnitude that lies within the physiological tolerance range.

The indication for an inclined plane is the setting of the incisors in the upper jaw, which are lingually tilted and clamped behind the lower anterior teeth (Fig. 10-68). In order to achieve stationary anchoring, the inclined plane encompasses at least all four incisors of the lower jaw without touching or irritating the gums.

Four incisors can be corrected effectively enough at the same time. During the correction of the teeth the periodontal tissue cannot be overloaded, as the periodontium ensures that the force is reflexively minimized.

If the distance to be bridged is very short, the success of the treatment is achieved quickly. Therefore, the correction of the tooth position without contact with the antagonist is first carried out with suitable active devices, then the adjustment with an inclined plane is carried out within a very short treatment period.

Reverse articulation of individual teeth is often associated with dislodging teeth in this area. The teeth to be corrected overlap and their movement is hindered. Therefore, the compression has to be corrected first.

In general, the incline is firmly cemented. However, it can also be combined with a removable device that retracts the lower jaw teeth at the same time. The lower incisors must bridge one half and the upper teeth the other half of the distance to be corrected. This is an active lower jaw plate with a tightened labial arch on which the inclined plane for the upper incisors is attached.

For the retrusive movement, the plate behind the lower incisors must be reduced. With the removable plate, the occlusal pressure is transferred to the upper and lower teeth to the same extent via the inclined plane. In order to achieve a stationary anchoring for the upper jaw teeth and for the lower jaw active components, the plate is anchored with the usual retention components.

The effect of the inclined plane depends not only on the angle of inclination but also on the number of teeth to be corrected, the distance to be bridged and the freedom of movement. If only one tooth needs to be corrected, the entire occlusal force acts on its periodontium and stimulates the remodeling. As the number of teeth to be adjusted increases, the force is distributed, as is the tensile and compressive action in the periodontal tissue of the affected teeth, until the force falls below a threshold and any orthodontic effect is lost.

The duration of treatment with an inclined surface should not be longer than 6 weeks, as the chewing activity is considerably restricted. The dentition must not come into contact with the antagonist, so that only the tooth or teeth to be corrected are loaded and repositioned. This leads to an elongation of the unloaded teeth, which can lead to an anterior open bite. The steeper the inclined plane, the faster the adjustment takes place.

An inclined plane is made in the laboratory using models. However, it can also be modeled directly in the mouth. The entire lower jaw is enclosed in a block with a splint to ensure a steady distribution of forces and to prevent at least the lower incisors from lengthening. The acrylic is pulled up so far that when you clench, only the affected tooth is touched by the acrylic block and all other teeth have no contact.

The acrylic bite plane is placed at a 45 degree angle to the occlusal plane. In the mouth, the surface of the bite surface can then be ground to the optimal angle of inclination. In several successive sessions (approximately every 3 days), the bite surface is then ground down until the incisal edge of the lower incisor is visible. The posterior teeth should not be in contact during the treatment period. Otherwise the inclined plane will not work.