Bite plate (splint) – Myorelaxing

Bite or splints

We usually do bite or myorelaxant splints on patients, who present strong occlusal wears caused by grinding (bruxism) or on clenching patients or with light muscular troubles and on dysfunctional patients.

The bites are real
functional devices whose main purpose is to correct the mandible dislocation positioning it in a correct therapeutic position;
the clinician establishes that position with specific tests (axiography) and he can set it with the help of the repositioning waxes or using the CPM in not dysfunctional cases, where it’s sufficient to know the condylar housing inclination, but not the complete path.
The bite can be a real “orthopaedic” appliance in patients with problematic cases, where it can be necessary to capture the joint disc or to remove an asymptomatic and symptomatic joint clicking.
Thanks to the information get from the clinician, the laboratory can set the articulator with individual values and realise a precision bite
A bite should have the following characteristics:
. Occlusal stability . Correct occlusal contacts . Canine guide . Protrusive check . The front sector must touch lightly the antagonist.
Normally I prefer to do lower bites for patient’s comfort and small dimension, but it doesn’t exist a real rule that shows us to work only on the lower maxillary.

Realisation

Assemble the models on articulator with the help of the dental face-bow in order to position the upper model in the correct three-dimensional position as the real one of the patient (see the figure).

Assemble the lower model on the articulator using the positioning wax (RP) with the articulator incisal rod on ZERO so that, once removed the wax, there is a gap between the upper and the lower model, big enough to realise the bite. This allows to build the bite without raising the vertical dimension on the articulator and to avoid rear rises of the plate once positioned in the patient’s mouth. (See figures).

Now it’s necessary to program the articulator with the data, dictated by the axiography or the CPM, with the RP waxes and protrusive technique. (See figures).

Axiography

At this point we can realise the bite; I prefer to press on the lower model a hard thermoplastic disc that is 0,75 mm thick and then cover it with an orthodontic transparent resin, but every technique is good (“salt and pepper” technique or firing in muffle, etc.).

The bite characteristics are very important:

  • . Canine guides
  • . The front group must touch lightly the antagonist (check with a Shimstock 12µ).
  • . The upper palatal cusps must get in touch with each other, while the buccal cusps must not touch to avoid interferences during right and left laterality movements
  • . Protrusive check of the upper canine.