The Jaw Recorder
Click on links to videos above to learn more about the Massad Jaw Recorder.
With the Jaw Recorder, any clinician can now quickly and accurately record Centric Relation, balance Full, Partial, or Implant Dentures, and orthopedically reposition the mandible. We have found that by using this device, results are more reliable and reproducible than any of the traditional manipulation techniques.
Record a patient’s Centric Relation
|“We use / recommend the Massad Jaw Recorder because of the ease of accurately establishing the vertical and jaw position. The overall benefit of using the tracer is reduction of tooth resets vs the traditional baseplate and bite blocks. The technique of taking a bite with wax rims is very technique sensitive and easy to create errors leading to tooth resets and additional chair time. We have been working with tracing devices for 25 years and the one thing about them is once a doctor has used a tracer, they do not go back to using base plate and bite rim.” Ken Waldo, CDT (Lord’s Dental Studio, De Pere, WI)|
An accurate, repeatable Centric Relation record can be made quickly and easily with the Jaw Recorder. Successful identification of Centric Relation results in fewer appointments to complete removable and fixed cases and less occlusal adjustments required at delivery of the case.
Record PRP: In order to find the patient’s correct Centric Relation, we must first accurately record the Physiologic Rest Position (PRP), commonly know as “resting position”. This is the position we most often find ourselves with teeth slightly apart during rest. Recording this measurement usually involves five simple steps: (1) place a dot for reference on the patient’s nose and chin, (2) coach the patient to their unique relaxed position, (3) adjust each leg of a caliper to the edge of each dot, (4) lock the caliper opening and transfer the measurement to paper, (5) adjust the pin on the Jaw Recorder to touch the maxillary striking plate at this measurement.
Adjust to OVD: By definition, the Occlusal Vertical Dimension (OVD) is 1-4 mm less than the measured PRP. After recording the PRP, and adjusting the pin to the striking plate at PRP, the pin on the Jaw Recorder is then adjusted to decrease the relationship to the maxillary striking plate 1-4mm, stabilizing the patient’s jaws at this critical vertical position. The patient is then directed through anterior-posterior and retruded lateral movements. The resulting path of contact between the pin and the striking plate traces the portion of a gothic arch tracing. The point of contact between the pin and plate at the point or tip of the arrow represents the patient’s unique centric relation and can be locked and stabilized with a bite registration material for accurate transfer to an articulator.
Balance Full Dentures, Partial Dentures, and Implant Dentures
One of the most difficult procedures in removable prosthodontics is finely equilibrating the occlusion of the finished prosthesis. Intra-orally, the prosthesis moves with every occlusal prematurity, producing erroneous marks with the articulating paper. Extra-oral remounts often incorporate inaccuracies, due to the remount procedure itself! The Jaw Recorder eliminates these problems.
When mounted on the finished prostheses, the pin and striking plate of the Jaw Recorder perform 2 functions. They act as a central bearing point, stabilizing the appliances through constant, centralized pressure. Secondly, the pin can be adjusted until the teeth are slightly apart, and then slowly closed. Through this gradual closure, the smallest occlusal prematurities can be seen and appropriately adjusted. This process is continued until occlusion is adequate and equal on both sides of the arch.
Orthopedically Reposition the Mandible
Many times, a denture patient will present a severely over-closed jaw position. It is important to return the facial musculature to the proper vertical position prior to final Centric Relation Recording. Muscles which are programmed to an improper occlusion will make Centric Recording difficult, and also make it difficult for the patient to adapt to the new prosthesis. Fabrication of an accurate occlusal splint will accomplish these goals. Splint therapy can be simple with the Jaw Recorder.
The Jaw Recorder is mounted on the patient’s current prostheses (or duplicates of them). The pin/striking plate relationship is adjusted, until the patient’s jaws are held at the desired OVD. An acrylic resin is then placed over the mandibular posterior quadrants, and the maxillary posterior teeth are lubricated. While the acrylic is in a “doughy” consistency, the patient is instructed to “rub” the pin against the plate in all directions, and to continue until the acrylic sets. After curing and trimming, a patient-generated splint has been fabricated at the correct OVD. The patient can wear this splint during denture fabrication, allowing the muscles to de-program.