Orthodontics: The Cantilever Wrap Around Appliance

by Timothy J. Tremont, DMD, MS

The author finds this appliance design to be exceptionally useful for maxillary retention. It is ideal for a well-finished case where the second molars are included in the final occlusion. Some of the features and advantages of the Cantilever Wrap Around Appliance are:

1) .036″ wire is used for both the cantilever arm and the labial bow. The labial bow is designed in a conventional fashion while contouring it gingivally around the first and second molars and in the embrasure. It is not necessary to engage any tooth undercuts. The cantilever arm is designed to lay adjacent to but not touch the gingiva. It does not impinge on the buccal mucosa. To provide support to the labial bow, the cantilever arm is approximately 3 mm superior and parallel to the bow. It extends to the middle of the first bicuspid and turns under where it is soldered to the labial bow. The labial bow and cantilever arm contact each other distal to the second molar.

2) There are no occlusal or interproximal interferences from support wires or clasps, which could open spaces or disrupt the occlusion. The patient’s occlusion can settle easily, especially if the acrylic is relieved on the palatal surfaces of the posterior teeth.

3) There is exceptional stability of the labial bow via support from the cantilever arm. The scalloping of the labial bow around the molars adds stiffness to the wire similar to corrugated cardboard being stiffer.

4) If there is a tendency for the labial bow to slide due to the inclination or contour of the incisors, the labial bow height can be adjusted up or down by using a three prong plier to place a slight bend at the midpoint of the cantilever arm.

5) There is excellent retention despite no active clasping. Retention comes from well-adapted acrylic to the palate, just like a “flipper”, and from light pressure of the labial bow on the incisors. The labial bow can be pinched in at the molar embrasure with a three-prong plier in the few instances when additional retention is necessary.

6) Although seldom necessary, acrylic can be added to the incisor section of the labial bow to control rotations.

7) Small pieces of cephalometric tracing paper can be used for checking the contacts of the labial bow on the incisors.

8) For a case with good anterior coupling, the lower cast should be occluded with the upper cast when the appliance is fabricated to make sure the lower incisors are not contacting the acrylic palatal to the upper incisors.

9) The author finds 10 hours per night of appliance wear is adequate for retention. If desired, the appliance can be worn 24 hours per day with the lower arch capable of full occlusion with the upper arch.

10) The appliance is exceptionally durable and breakage would be very unusual.

Dr. Tremont is a Clinical Assistant Professor, Department of Orthodontics, West Virginia University School of Dentistry and is in full-time private practice in White Oak, PA.

Oral Health welcomes this original article.