Case Background
Initial view of the buccal aspect of the mandibular right first molar showing a heavily worn clinical crown.
Case Treatment
The dual arch impression technique is an extremely accurate method for obtaining an impression of a few teeth in a dental arch. It involves the use of special impression trays to capture the prepared teeth, centric occlusal relationship and the opposing dentition. In essence, all the information needed to fabricate a prosthesis accurately. The Temrex Bite Relator has metal walls to help support the impression material and prevent distortion especially when pouring models.
Bite Relator Impression tray in place. In order to confirm an accurate occlusal record we checked the occlusal relationship on the contralateral side.
In this clinical situation, we restore the mandibular right first molar with a PBM crown. The tooth was prepared for the PBM. The impression tray was selected that conformed to the shape of the arch and did not impinge upon the alveolar tissue. I typically will use either the Wide or Xi tray since they allow me to capture the teeth in the posterior sextant.
View of the impression of the tooth preparation
Models mounted with completed PBM crown.
When the impression tray was seated, we checked the occlusion on the contralateral side to ensure that the patient was occluding in centric occlusion. The lab then poured the impressions using the Bite Relator occlusal record for mounting. We checked and confirmed the mounting when the crown was returned. The crown was seated using Temrex Bite Sticks and cemented with no adjustments. We have found that we have had less than 1% remake using this technique. There is very minimal to no occlusal adjustment required when seating the crowns.
Post Op
PBM crown in place on the mandibular right first molar, re-establishing the correct occlusal relationship.
Research has confirmed the following:
- Bite Relator produced models as accurate as full arch acrylic custom trays.
- Bite Relator was more accurate in reproducing the tooth-to-tooth relationship than plastic trays or custom trays.
- Crowns produced using the Bite Relator fitted as well as those made with a full arch custom tray.
- Bite Relator produced accurate casts from second pours of the same impression.
- Bite Relator is more likely than plastic trays to produce castings with acceptable marginal integrity.