R E L I N E S
“I sent a reline to the lab and the bite is now open half an inch
in the anterior, what happened?”
By Larry R. Holt, DDS,
Things can easily be messed up during a reline process. But, if you take a little extra time and follow a protocol, you can easily get nice results too.
First, is the denture worth relining? Really old dentures are typically worn and the acrylic is not amenable to accepting new acrylic.
Its ok to tell a patient that their denture is ready for the scrap heap!
First (a second time) its very difficult to make major corrections on tooth position by performing a reline. It happens accidentally on occasion, but when attempting to do something like intentional lengthening for more tooth reveal, its very difficult to be predictable. This is a procedure to refit the intaglio surface, not to realign the teeth.
Remember, all relines are closed bite impressions. If you take the reline impression open mouth, it is almost impossible to maintain proper occlusion. Even when doing both arches, keep the opposing in place so that you can keep up with bite relationship.
Denture preparation prior to reline procedures:
• Remove any soft liner completely
• Evaluate the denture for any undercuts
These must be removed in order for your technicians to pour a model and recover it without breaking the resultant model.
Note the undercuts in the illustration in the anterior and over the right tuberosity.
- Mark the patient’s vertical - Use the old line on the nose and chin and a tongue depressor. Make sure you are not changing the patient any more than necessary.
|Regardless of one arch or both, its important to know what the
bite looks like before you start. (Please note the use of a clear denture for
Impression materials of choice for most relines will be Polyvinyl Siloxane. Border molding can be accomplished with fast set heavy body and final WASH impressions will be done with light body regular set material. BE SURE TO USE ADHESIVE.
Border moulding can be accomplished in segments or in it entirety. I suggest doing it in segments until you become more confident in handling the material and its set time. Note the amount of material being placed and that some is applied in the rugae area. This serves as a spacer and as a guide for proper seating of final wash.
- Go through all typical border moulding steps now and when you apply the wash material. Be sure the occlusal relationship is not changing.
Once satisfied with the border moulding, apply a thin layer of light body, regular set PVS to the entire intaglio surface. This should be about 2mm or less thick. Too much and this becomes an impression and not a “wash”. You can remove excess material with a disposable brush. Insert into mouth, have patient gently close into full occlusion. (warn patient to bite gently and not to apply to much force, the heavy body in the palate and in the tuberosity area helps to avoid over seating) Once seated, border mould again for the first 2 minutes. Be sure a timer is set and follow manufacturer’s directions.
Remove and admire your excellent wash impression!
As a rule of thumb, you should be able to see the initial border moulding just through the surface of the wash. An additional test can be done by taking a periodontal probe and measuring the thickness of the wash in multiple locations. It should not be over 1-2mm except where you relieved undercuts. Also, compare your initial VDO measurement to see that vertical has not changed.
Once this impression has passed inspection, continue with the opposing arch or send to the laboratory if single arch. On this subject, it can be difficult to maintain occlusal relationship when relining both arches at same appointment. Some clinicians choose to do one arch at a time.
In review, the keys to denture relines are:
• relieve undercuts and remove any temporary reline material
• keep up with vertical dimension
• take all impressions in occlusion with opposing
• border mould with heavy body to define borders and create stops
• USE ADHESIVE
• use a thin coating of light body, REGULAR SET material for final wash impression
• be sure to use all border moulding procedures while wash impression is setting
• follow manufacturer’s instructions for setting times.
• measure thickness of reline impression in several spots and check vertical
As with most things in dentistry, the details matter.
Till next time,