The Pendulum Appliance: Creating the Gain-

An Update on the Latest Generation of the "Noncompliance Appliance"

By Randall K. Bennett, D.D.S, M.S., Salt Lake City, Utah and James J. Hilgers, D.D.S., M.S., Mission Viejo, California.

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The Pendulum Appliance was created several years ago by Dr. James Hilgers to meet the needs of a growing number of clinicians who were beginning to understand that good patient compliance was just not forthcoming in a great many of cases. Since the orthodontist is still charged with the responsibility of correcting the malocclusion, approaches that minimize patient cooperation are becoming ever more popular. Hilgers coined the term, "noncompliance therapy," to describe a whole series of appliance mechanics over which the patient has little or no control but that has the potential of achieving excellent and, perhaps just as importantly, predictable results. This article is the first of a two part series intended to describe the current state of the art in the clinical use of the Pendulum or Pendex (Pendulum with expansion) Appliance.

Since its introduction, the Pendulum Appliance has undergone numerous changes that have greatly improved patient comfort, eased appliance placement and activation, simplified design, enchanced stability and improved overall response. Several variations have evolved and are being used successfully. With this update, we will illustrate the fabrication of the current design as it has evolved and is now employed in our offices.

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(You can view the illustrations by clicking on the highlighted text or by clicking on the thumbnail image of the image. The file size is indicated with each illustration.)

Placement and Activation:

Placement of the Pendulum appliance is now accomplished in a manner that maximizes patient comfort without compromising appliance activation. The appliance is often fabricated using a model that is created at the initial examination. As all the activations of the Pendulum Springs are made chairside at the time of appliance placement, it is not necessary to even have the bands with the lingual sheaths on the model. After the molar bands and attached lingual sheaths have been cemented, the fabricated appliance is placed in the mouth and held in place with finger pressure so that the occlusal rests are completely seated in the respective fossae and the acrylic portion of the appliance fits comfortably against the palate. To begin the activation process, a wax pencil is used to mark the outward extension of the pendulum spring. This mark is made at the most gingival point of the lingual sheath so that a rounded right-angle bend can be made and the distal extension of the spring can fit passively into the sheath. This aids greatly in the intraoral placement of the springs and avoids placing undue pressure on the bonds if the appliance is expanded. The spring is bent at a rounded right angle at this mark Marking Wire at Sheath (59KB) Wires on Cast (72KB)

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so that the two distal legs are parallel to each other. The wire is clipped so it is no longer than the mesio-distal length of the lingual sheath (5 mm.)

The Pendulum Springs are then activated for distalizing pressure by holding the center of the helix with a Tweed or other conical plier. The spring is bent at the helix to a point parallel to the midsagittal line. The two distal ends of the springs should approximate each other. The appliance is then placed into the mouth to make sure that the activated springs do not impinge on the soft palate. The teeth are conditioned and sealed in preparation for the final appliance placement. A small amount of bonding medium is exuded into the fossae of each of the appropriate teeth using a CR syringe and the appliance is placed back in the mouth. Normally, this small amount of bonding medium is adequate, but more can be added to each tooth as required at this point. The idea is to seat the appliance into the bonding medium rather than just flowing the acrylic over the top of the occlusal rests. The bond is then smoothed with a mixture of sealants so that no further contouring is required. The appliance is held up against the palate with finger pressure for approximately two minutes, then released and allowed to set for another three minutes before attempting to fit the activated Pendulum Springs into the lingual sheaths.

After this five-minute period, the Pendulum Springs are drawn back and placed into the lingual sheaths. This is best accomplished with a Weingart (Howlet) plier holding the distal portion of the spring at the right angle bend. This is especially important if added rotation of the spring has been incorporated to accentuate disto-rotation of the upper molars. The springs need not be tied into the lingual sheath in any manner, as the ditalizing pressure will hold them securely in place. The midpalatal jackscrew is activated slowly (one turn every other day) to avoid tissue impingement and to achieve the desired arch form and expansive changes that are required in the correction of Class II malocclusion. The authors have found that the distalizing effect of the appliance is greatly enhanced by this expansive moment and certainly avoids bringing the upper molars into crossbite as they are moved distally.

Unactivated Appliance Activated Appliance

Appliance Seated in Mouth Progress photo

Part II of the two-part series, "Maintaining the Gain", will focus on the specific mechanics required to hold the molars in Class I position while the rest of the maxillary dentition is retracted. The cephalometric synopsis of 15 sequentially-treated Pendex cases will be highlighted to help the clinician evaluate anchorage, case selection and anticipated results.

Fabrication (220 KB)

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