Impression Adhesives and Remake Reduction

Clinical Update – Remakes and Impression Adhesives

Remakes are frustrating for all concerned, the Doctor in thier busy office, the patient who takes time away from work or family, and the laboratory personnel who fabricate the restorations. It can be difficult to determine the cause of remakes. Having procedures and systems in place which help give reliable and predictable results can go a long way towards eliminating remakes.

At Oral Arts, all remakes are tracked, and whenever possible we look at the previous impression, master cast, and restoration, and compare them to the new impression and master cast to see if a cause can be determined. Each remake is logged in by case number, type of restoration, Doctor’s reason for the remake, and the laboratory’s findings by reviewing all the above mentioned materials. What we find is that many restorations fit the original master die, but do not seat on the new master die.

After months of evaluating these cases and analyzing the data, a common occurrence has been noted: lack of adhesive used on impression trays. Visits to websites of major manufacturers of impression materials and follow up phone calls to technical support were made. Every manufacturer called recommends that tray adhesive be used with their impression material. Adhesive should be used even on perforated trays, and placed on all surfaces that will come in contact with the impression material. The adhesive bonds the impression material to the tray, minimizing the risk of distortion.

Not using adhesive gives unreliable results; one will never know which impression may distort. If you have noticed in your clinical practice that the crowns fit the die, but when tried in the mouth you find the following:

• Crowns fit too tight, high crowns
• Extensive occlusal adjustment is needed
• Tight or loose contacts

The impression could be distorted from not using adhesive. Other causes could be not allowing the adhesive to dry, or using the wrong type of adhesive. If you have recently had a staff change and noticed an increase in your remakes, it may be due to someone not knowing to use adhesive on your impression trays.

Use the manufacturer’s adhesive specific to the material you are using and follow its instructions for use. They all vary slightly as to the time allowed for the adhesive to dry prior to the impression being made, usually from 5-10 minutes.