How to Eliminate Unnecessary Occlusal Splint Adjustments

By Doug Willison, Senior Outside Sales Representative, Great Lakes Orthodontics, Ltd.

When having conversations with customers or perspective clients who are frustrated with the amount of chair-side adjustment required to seat their full coverage occlusal splints, the problem most often can be pinpointed to two areas: face bow mounted casts and an accurate Centric Relation bite record.

Cause 1: Missing Face Bow Mounted Casts
When a laboratory is not supplied with a face bow mounted set of models, they are required to place them into an articulator by some other means. Some laboratories have specific jigs that will allow them to place the model into a semi-adjustable articulator via averages. In most cases, these averages will place the maxillary incisors at 100 millimeters from center of rotation at a 12-15 degree occlusal plane angle. Consequently, the first area of adjustment concern comes from those patients that begin to deviate from the averages, creating arc of closure issues into the occlusal aspect of the splint. The further the deviation from the average, the further off the contacts can be.

Cause 2: Missing or Inaccurate Centric Relation Bite Record
Even a great set of mounted models will not eliminate the need for splint adjustment if an accurate centric relation bite is not provided. The goal for a permissive splint is to have the joints fully seated and even contacts all around with immediate disclussion. Feedback from splints with incorrect contacts often points to having occlusal contact of the splint at seating in the molar area only.

In many cases, this can be related to the joints not being fully seated into their most superior position in the construction bite. Therefore, when a splint is introduced and the patient’s occlusal scheme is removed, the ptyregoid muscles release while the elevator muscles seat the joint into its natural position. This results in only the posterior portion of the splint being in contact. This creates much aggravation for many who have to spend, at times, up to 40+ minutes to get the occlusion of the splint properly adjusted.

The Solution
This problem can be easily remedied by taking a small amount of time at the front end with accurate centric records. In addition to the Gold Standard of bi-manual manipulation, items such as Lucia Jigs or Aqualizers, can aid the user in helping get to the proper joint position for splint fabrication.

In order to make the splint experience as efficient as possible you should strive to provide the following for any permissive splint:

• • Stone models that have been mixed with the proper powder to water mixture as recommended by the manufacturer. Whenever possible, these models should be vacuum spatulated to eliminate porosity.
• • Face bow mounted casts on a semi-adjustable (SAM, Denar, Kavo to name a few) articulator.
• • A Centric Relation bite taken with Bi-manual Manipulation or with one of the aids described earlier to assist in the release of the ptyregoid muscles and fully seated joints.