THE EDITOR'S CORNER

The article by Dr. Alain Benauwt which appears on page 278 of this issue was like the echo of a distant bell to me. He is dealing with what have been named by their originator "Plaques a Tubes" or Tube Plates. As you will see in the article, these are active removable plastic appliances in two sections, one of which slides, for backward or forward movement of teeth.

Many years ago I sought to devise a passive removable plastic appliance which would open the bite without interfering with the distal movement of the upper anterior teeth. It was intended for closed bite cases with protrusion of the upper anterior teeth where the bite closure interfered with the retraction of the upper anterior teeth. This could be in full-banded cases which did not respond to other bite-opening techniques, or less than full-banded cases, such as upper headgear cases. Even if I have learned to open bites better now than I could then, there are still cases in which it would be advantageous to be able to open the bite and achieve distal movement of the upper anterior teeth using less than a full-banded appliance, or to open the bite in full-banded cases in which the bite-opening technique is not working due to archwire distortion or clenching.

In attempting to devise an appliance to accomplish this job, my first design was an anterior bite plate. It consisted of just the bite platform portion of a normal bite plate. It was retained with a labial frame and/or spurs. When it was placed on an arch with full upper bands and an archwire, it had short vertical projections with bulbs of solder on their ends which engaged inside and gingival to the archwire. It snapped into place and retained fairly well. It was reasonably successful, but I discarded it because of the concern that one day somebody was going to swallow one of them.

This was followed by something very much like a tube plate. It was a sliding post-in-tube assembly which permitted the bite to be opened by the anterior sliding section, and to be held open by continuous use of the appliance as the anterior teeth and the anterior bite plate section moved distally in response to elastic or headgear force. I have rummaged through my storage and I have found one of these which I show you here in its fully extended and fully retruded positions.

The way that this appliance was made was that two equal lengths of .060 I.D. tubing were cut for the posterior section of the upper model. Two longer lengths of .059 wire were modified by making them half-round for all but a short section of their distal end. The round wire was slid into the round tube and the mesial end of the tube was crimped over the half-round section of the wire. This created an assembly in which the wire slid in the tube without pulling out of the tube. With the wire pulled out as far as it would go and bent toward the mid-line at its mesial end (to retain it in the plastic of the anterior section), the assemblies were seated parallel on the model. A wax barrier was laid across the mid-section and acrylic was cured over the tubes in the posterior end, and the ends of the wires in the anterior bite plate section. Any suitable clasping and wiring was used.

The result was a sliding bite plate. I tried several of these with variable success. Sometimes it worked. When it did not, it was because the section was not free-sliding enough. I think I should have persisted. The idea was a good one. It was workable and just needed perfecting. I wonder how many other ideas have had a similar fate.