TROUBLE SHOOTING
3. Divot developed in the Discluding Element
4. Development of an Anterior Open Bite
1. Enhancing Retention
To extend the device to enhance retention, more thermoplasticbead (TPB) can be added to existing cured TPB material. "Flamebrush" the external surface of the existing TPB material thereby creating a "sticky" surface. Heated TPB material in the clear putty stage will "bond" to the sticky layer, and can be manipulated to extend the extensions of the device.
2. Extreme Protrusion - Patient "falls off" the distal end of mandibular DE is protrusion.
Above left shows the patient's full protrusion, with the distal end of the DE arriving at the labial side of the maxillary incisors. The remedy is to add acrylic to the distal end of the DE. Mark the distal end of the DE with pencil prior to adding acrylic, so as to provide a visual guide (shown above middle). Above left, final delivery in full protrusion. The pencil line at the distal end of the DE can be seen (the occlusal surface at the distal ends was reduced to prevent occluding with the maxillary molars)
3. Divot in the DE
Once a therapeutic result has been achieved, and a divot in the DE appears a period of time later, do not reduce the level of the DE to the depth of the divot, but restore the divot with acrylic or composite restorative material. The image on the right shows the surface of the DE of a Lower Device, with the wear indications of lateral excursive parafunction. The is no need to fill in the wear, or to polish down the surface.
4. Development of an AOB
There is a concern expressed by some practitioners that long-term nightly use of an NTI device will cause "supra-eruption" of the second molars (but curiously, not the first molars, bicuspids, etc... There are no published orthodontic studies describing the method of intentionally extruding a molar that includes both the LACK of any attached brackets, or, use of any removable device that DOES NOT come into contact with the molar, while still providing for daily, unsuppressed occluding forces. In one study observing over-eruption of teeth without antagonists, it was concluded that tooth eruption was largely age-dependant and not all molars without antagonists overerupt, not even in a long-term perspective.
A potential diagnostic revelation of NTI use is the development of an anterior open bite, of which the majority of the time occurs as a result of the reorientation of the condyles following normalization of the musculature, particularly the lateral pterygoid. (Dynamics of condylar seating ) This can only happen if the condyle(s) were in a position anterior and inferior to their optimal musculo-skeletally stable position, and then reposition to a more posterior-superior position. This causes the mandible to pivot/rotate at the most posterior molars (thus giving the appearance of posterior supra-eruption), allowing the condyles to seat more posterior and superiorly, while the anterior mandible rotates posterior-inferiorly, which, depending on the degree of the initial incisal overlap, may present as an anterior open bite.
As with any procedure, where a variety of outcomes is possible, all reasonable outcome scenarios should be disclosed. For the patient, the NTI-tss may prove to be both a symptomatic treatment device, and a diagnostic device which demonstrates that the condyles were not in their optimal seated positions. However, the treating dentist may not desire to be involved in the treatment modalities necessary to provide a occlusal scheme to the patient's satisfaction, in which case the dentist may elect to not provide treatment with the NTI-tss.
5. Appearance of a click
An excessive vertical dimension created by the Discluding Element can reveal the presence of an anteriorly displaced disc. Reducing the VDO, especially in extreme protrusion is recommended.