Providing Accurate Guidelines for Redo and Repair Cases
As a dental technician, I often encounter situations where doctors inadvertently provide incorrect instructions when sending cases back to the lab for redo or repair. To achieve the best possible outcome for the patient, here are some key considerations to keep in mind.
When a crown is seated but the interproximal contact remains open, a completely new impression is not necessary. Instead, the doctor should take a pickup impression with the crown in place. This allows the lab to make precise adjustments to the contact without requiring an unnecessary remake.
If the crown margin is open or too short, taking a new impression is absolutely essential. Minor adjustments cannot correct significant marginal discrepancies, and in most cases, a complete remake is required.
A common mistake is taking a pickup impression while leaving the crown in place. While this may help the lab visualize the issue, it does not provide the accuracy required for fabricating a proper replacement. The lab cannot make precise corrections using only a pickup impression.
For hypo-occlusion (when the occlusal contact is too light), the doctor should seat the crown in the patient’s mouth and take a blue bite registration to indicate the exact occlusal gap. This allows the lab to determine the required material adjustment.
For hyper-occlusion (when the occlusion is too high), there are two recommended approaches:
Leave the crown in place and take a bite registration before sending it back to the lab.
Remove the crown and take a separate bite registration, which provides even greater accuracy.
A frequent oversight occurs when a doctor assumes a bridge crown has hypo-occlusion and sends it back to the lab. However, in many cases, one of the crowns within the bridge is actually hyper-occlusal, causing the adjacent crowns to appear hypo-occlusal. This misunderstanding often goes unnoticed because the lab may not communicate the exact cause of the issue. The safest approach is to remove the crown and take a new blue bite registration.