JCO 68 a Hygienic Appliance Rapid Expansion HYRAX

JCO-Online Copyright 2011

A Hygienic Appliance for Rapid ExpansionVOLUME 2 : NUMBER 02 : PAGES (67-70) 1968WILLIAM BIEDERMAN, DDS

It is generally believed that orthodontic forces affect the alveolar process only. Rapid palatal expansion as re-introduced by Haas1 , is asignificant advance in maxillary orthopedics. It opens the mid-palatal suture and widens the apical base, thus negating the conclusion ofLundstrom2,3 that the apical base is unchangeable.

Rapid expansion is particularly indicated where the vault of the palate is high and narrow, and when the patient has not yet reachedmaturity. Heretofore, one drawback has been the soft tissue irritation caused-by food impaction under the acrylic plate (Fig. 1). Thehygienic appliance eliminates this problem.

The technique

1. Seamless bands are adapted to upper first molars (.018 X .005) and first premolars (.150 X .004). These should be a half-size largerthan necessary and fit below the gingivae.2. An impression is taken with the bands in place. The impression is removed. The bands are seated in the impression and secured withsticky wax.3. Pink wax is melted into the bands toward the buccal and lingual to facilitate soldering.

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4. A stone cast is poured, separated and trimmed. All excess stone is removed from the surface of the bands. The pink wax iseliminated with hot water.5. The metal guard on the Fischer screw is removed and replaced. This makes it easier to remove later. A little mound of fast-settingplaster is put in the center of the moistened cast and the screw is positioned so that it is well away from the palate and equidistant fromboth sides. The screw is oriented so that, on activation, the key is pushed backward. This is important.6. The sides of the screw are carefully covered with a thin coat of plaster by means of a camel-hair brush. The coating acts as anti-flux.Excess plaster, which might interfere with soldering, is trimmed away.7. .040 round wire is adapted to the buccal surfaces of the bands with sufficient excess to permit its temporary attachment to the castwith sticky wax.8. .059 round wire is fashioned so that it simultaneously touches the screw and the lingual surfaces of the bands, with the wire a littlelonger than necessary.9. To tack these lingual or palatal .059 wires in place, flexible .020 wire is welded at right angles to the .059 wire near the ends. A slightcut with a carborundum disc at the welding site and a slight flattening on the opposite side of the wire, by grinding, makes weldingeasier.10. Once the buccal and lingual wires are adapted and tacked in position with sticky wax, soft plaster is applied to hold them there.11. Silver solder is used. The .040 buccal wires are soldered first. Then the .059 wires are soldered to the lingual of the bands. Finally,the .059 wires are soldered to the screw.12. The excess buccal and lingual extensions are cut off. The cast is plunged into cold water. The stone under the buccal aspects of thebands is undercut to facilitate the removal of the appliance from the cast with posterior band-removing pliers No. 347.13. The screw is lubricated with light oil, activated about 6 mm, and closed. This is done several times to loosen the action. Theappliance is then ground, finished, polished, and replaced on the cast. The appliance is now ready to try in the mouth.

Insertion and activation

After removing the separations between the teeth, placed there at the previous visit, the appliance is tested for fit. It is then removedand both patient and parent are instructed on how to activate the screw. Silk grassline is tied to the key to prevent slipping in themouth. Once the patient and parent are familiar with the working of the appliance, it is cemented into place.

The patient is instructed to activate the screw twice daily. This means an increase in width of mm. Once activation is complete, theappliance remains undisturbed for three months to permit filling in of bone in the suture.


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At the end of the activation period a diastema usually occurs between the centrals (Fig. 2). This is a self-correcting and transitoryphenomenon (Fig. 3 ) . While waiting for the suture to fill in, the lower arch may also be treated.

Although activation morning and evening seems radical, the patient experiences no pain, only a sense of pressure at the time ofactivation which quickly disappears. The results are dramatic both in the effects and the brevity of treatment. It is a most valuableprocedure no matter what philosophy of treatment one follows. It unquestionably reduces the need for extraction in many cases.

The new screw assembly

I have been using the technique described for a long time with great success. I have recently designed a new type of screw which hasjust been manufactured (Fig. 4). The heavy lingual wires are attached by the manufacturer which greatly facilitates the solderingoperation.

To use the new screw--

Prepare the stone model with bands as before. The OIS screw is placed on this cast with the red dot to the posterior.The heavy wires are adjusted so that they cross the middle of the bands. The screw is lowered toward the palate by bending the wiresas near the screw as possible. When the screw is 5 or 6 mm from the palate, mark the wires where they cross the lingual of the bands.Bend each wire about 3 mm medial of the mark and adjust all four wires so that they are in contact with their respective bands in sucha way that subsequent soldering does not impinge on the gingival quarter of the bands.With a pencil, mark the location of the wires on the cast and outline the screw. Put a little mound of soft plaster on the palate andreplace the screw so that all four wires touch as before.After the buccal wires are fashioned and adjusted, the technique proceeds just about as previously described.

The new OIS screw greatly simplifies the laboratory procedure for fabricating the hygienic appliance. It is especially helpful in eliminatingthe need to solder wires to the screw.

Figures

Fig. 1 Soft tissue irritation immediately after removal of acrylic palate appliance.

Fig. 2 Clinical picture before and after palatal expansion treatment with hygienic appliance.

References1. Haas, A.J.: Rapid expansion of the maxillary dental arch and nasal cavity by opening the midpalatal suture, Angle Orth. 31: 73,1961.

2. Lundstrom, A.F.: Malocclusion of the teeth regarded as a problem in connection with the apical base, Int. Jour. Ortho, Oral Surg.,and Radiography, 11:591 et al, 1925.

3. Ibid: Concerning the effects of orthodontic treatment on the maxillary and mandibular bases, Int Jour Ortho, 14:135, 1928.


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JCO 68 a Hygienic Appliance Rapid Expansion HYRAX