Distalization of upper buccal segments has traditionally been accomplished with headgears, or with removable appliances combined with headgears, such as the ACCO appliance. Other distalization modalities have been devised, such as magnetic modules, Herbst appliances, various jigs and jumpers, pendulum appliances, etc., all testifying to the desire of the orthodontist to free himself from the tyranny of the headgear, that is, to shift control of the appliance from the patient to the orthodontist.

The appliance to be described will rapidly distalize the upper molars and increase the arch length. The distalizing force is produced by a rectangular nitinol spring. (Fig.1 and Fig. 1a)

The appliance typically consists of two bands on the first bicuspids, a soldered interconnecting wire, and a palatal button similar to the Nance holding arch. The palatal button is extended behind the upper teeth to form a bite plate. Small rectangular molar tubes, .0l8 x .025, (Dentaurum 725060-00) are welded horizontally on each first bicuspid band. These tubes serve as guides for the rectangular distalizing springs. It is important to use rectangular tubes , as round tubes would cause the springs to rotate buccally into the cheek instead of being held vertically. This appliance is used generally at the start of treatment, before brackets are placed, although if circumstances require, it can be used at any time afterward if additional molar distalization is required. In this case, brackets would be temporarily removed from the first bicuspids in order to fit bands.

CONSTRUCTION OF THE APPLIANCE

Molar bands with single or double tubes are cemented on the upper first molar teeth. Next, bicuspid bands are fitted on the first bicuspid teeth. In many cases it is not necessary to use a pre formed band. A strip of band material, .l80 x .005 (Rocky Mt. order number B-l0l) can be pinched around the tooth, festooned gingivally, contoured with a ball and socket pliers, and welded.

An impression of the arch with bicuspid bands in place, but not cemented, is taken with warm impression compound. Alginate is not suitable for the impression, as it is not rigid enough. Compound is ideal for this purpose: it is very rigid and can sit on the bench indefinitely without losing accuracy.

The bicuspid bands are removed from the teeth and replaced in the impression. A large drop of sticky wax is placed in the lingual of each band to facilitate soldering and the model is poured. After setting, the impression and model is placed in hot water and separated. A connecting wire, .030 or .036, is soldered to the bands and self curing acrylic is added. A bite plate is created behind the upper anterior teeth. After curing, the appliance is removed from the cast, trimmed, and then polished. (Fig.2)

A 2 mm. groove is cut into the tissue surface of the appliance behind the central incisors to facilitate cleaning underneath the appliance with a syringe.

The finished appliance is inserted in the patient's mouth and adjusted to fit. The bite plate is adjusted for the proper degree of opening, and the tubes are welded onto the bicuspid bands, making sure they are parallel to the molar tubes both horizontally and vertically. I usually tack weld the tube with one weld and adjust it before welding it completely.(Fig 3) The appliance is cemented into place with glass ionomer cement and the springs inserted.

Fig.3

The springs are bent from short lengths of .0l8 x .025 rectangular nitinol wire, incorporating a U-shaped vertical loop at the distal to fit into the molar band tubes. Five or six mm. of wire is allowed to protrude anteriorly from the bicuspid tube to allow for subsequent activation. The anterior 2-3 mm. should be annealed by heating to a red heat. This will allow it to be bent inward to avoid irritating the lip. Before insertion, a Masel Grip-tite archwire lock is installed on the spring near the vertical loop. Activation is accomplished by compressing 2 or 3 mm. against the molar tube, sliding the lock forward against the bicuspid tube and tightening securely. A curved tip disposable syringe (Monoject 4l2) is given to the patient, who is shown how to use it to flush food debris out from underneath the appliance. The patient is dismissed after being instructed that the posterior open bite caused by the appliance will soon disappear. Figures 4 and 5 show the springs before and after activation.

Fig. 4 and Fig. 5

The patient is seen in one month, the springs are activated and the patient can be dismissed. The whole procedure takes a minute or two. It is not uncommon for the posterior teeth to be in occlusion again in three or four visits and the molars fully distalized. I usually overcorrect the upper molars into a slight Class III relationship, to allow for any relapse. When the molar teeth are fully distalized (Fig.6 and Fig7), usually in four to six months, the appliance is removed and a bonded bracket set-up is done at the same visit.

Fig.6 and Fig. 7

Note Super Class I

The distallized molars are held in place by means of a super elastic nitinol arch with bent-in posterior loops (Fig.8)

Fig.8

This arch maintains the molar distalization while allowing correction of rotated and inclined anterior teeth. With a little practice and perseverance one can bend loops in super elastic wire using a three pronged clasp adjusting pliers. When the upper anterior teeth are leveled and rotations corrected, the arch may be removed and replaced with a Class II mechanics set-up, and the case is finished in the usual way.

The distalizing appliance may be used on the lower arch, but it is more difficult to construct and fit, as the mandibular lingual tissues are thinner and more sensitive than the palate. I usually prefer to use a lower lip bumper, if needed, provided the crowding is not too severe. Naturally, if the lower arch is very crowded, perhaps a bicuspid extraction approach should be considered.

• The appliance is cemented in place and not subject to the patient's control.
• The molars distalize rapidly due to the constant light force exerted by the springs, and also due to the disclusion of the posterior teeth.
• Headgear is unnecessary.
• The bite opens automatically as distalization progresses, due to the built-in bite plate.
• The springs are inexpensive: four can be made from one 7" straight length of .0l8 x .025 nitinol wire.
• Appliance adjustment is very rapid; the springs can be activated in a few seconds by moving and tightening the lock.

• The palate is sometimes inflamed after the appliance is removed. This condition clears up in a day or two.
• Occasionally, the upper anterior teeth move slightly forward and the first bicuspids may tip mesially. Although this may be a little disconcerting at first, experience has shown that the nitinol holding arch followed by Class II mechanics will allow the anterior teeth to resolve naturally. The appliance acts to increase arch length, and although most of the movement is distal, some mesial movement may occur. It should be obvious that if the molar relationship is Class I or slightly Class III, the anterior teeth will retract properly under the influence of Class II elastics.

• The appliance is useful for the following malocclusions:
• Class I malocclusions.
• Class II malocclusions, both div. l and div. 2
• Class I malocclusions with anterior lingual crossbite, if the molar teeth are immobilized with a Goshgarian palatal arch or similar appliance. In this case most of the movement of the upper teeth will be mesial.
• The appliance is particularly suited for treatment of Class II, div. 2 malocclusions, which usually have severely closed bites.

A future article will discuss individual cases treated with this appliance.

Dr. Richard Vlock received his DDS from NYU College of Dentistry and his Certificate of Proficiency in Orthodontics from Columbia University in New York. He is currently engaged in private practice in Gloversville, New York. You can reach him directly at: rvlock@klink.net