There are many techniques for capturing a centric relation bite record. I have spent time becoming comfortable with all of them because in different clinical situations, each may be the technique of choice. One of these approaches is to capture the record utilizing a lucia jig. The purpose of the lucia jig is to separate the back teeth, release the elevator muscles, which will then release the lateral pterygoid. Placement of the lucia jig during a bite record creates a tripod effect with the three legs of the tripod being the anterior contact on the jig and each of the condyles.
The first step in capturing this type of centric relation record is to fabricate a lucia jig for the patient, and allow the patient to wear it for 10-15 minutes
if necessary. Using articulating paper I mark the retruded or centric relation contact on the lucia jig. One of the challenges of a lucia jig, is that patients can posture forward or bite in protrusive without us detecting it. The mark allows me to observe where the patient closes with the bite registration paste in and verify I captured the correct position in the record. The next step is to dry the maxillary teeth completely. I always place the silicone bite registration against the maxillary teeth as the tongue will wipe it away off the mandibular teeth. With the teeth dry I inject a wide band of silicone bite registration material over the maxillary posterior teeth up to the canine on each side. You want the band of silicone to cover the buccal and lingual of the teeth and be 4-5 mm in thickness. This requires moving very slowly as you inject the material so that it builds up behind the tip. The thickness and broadness of the material is what makes trimming it and mounting the models possible when we get to the lab.
With the silicone in place, I ask the patient to close “On your back teeth”. As they close I observe to make sure they close against the mark on the jig. If they close into a different location, I wait until the material sets and then we can try again. Often difficulty having the patient close into the same location indicates muscles that are not released. In this situation it may be best to utilize an appliance to accomplish this prior to taking CR bite records for final diagnosis.
Hi Lee Ann, great website! Just a quick question from a novice……when do you mount in CR opposed to mounting in MIP? Is it only if you plan to restore an entire arch?
Lee Ann Brady says
This topic probably requires more then a quick response, but I will give it a try. First I mount in CR when I take full arch diagnostic casts. As part of my diagnosis, if I will be doing an appliance or a wax-up, one of the questions I want to answer is where will we do treatment in CR or in MIP, or possibly in a treatment position. Now many of my cases are basic restorative care ( single crowns, composites, etc.) and we are arbitrarily treating in MIP, due to the fact that the dentistry will not have a significant occlusal impact, or because there isn’t evidence of occlusal disease that makes me concerned prior to doing an occlusal analysis, so we proceed without diagnostic mounted models. All bite records for restorations need to be taken at the VDO of the restorations, so MIP, otherwise you will introduce an error that results in lots of chairside adjustment. So as you can see, lots of other questions in my answer.
ADITI ARORA says
IF ANTERIOR UPPER ND LOWER TEETH ARE MISSING THEN HOW WE CAN USE LUCIA JIG TO RECORD CR
Lee Ann Brady says
You can use upper and lower wax rims and a gothic arch tracer, or copper bite trays from Panadent.
can i ask about Criteria for a good central occlusal marker when using jig ??
Hello Dr. Lee Ann,
How can you fabricate one if you don’t have ready made jig?