3M ESPE User Manual

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Suggestions When Using the Dentures as Trays  
for Final Impressions
Single Stage Impression Technique
When using a one-stage impression technique — using a single phase impression material — use 
a MEDIUM BODY VISCOSITY. Light body can result in too thin a layer of impression material and 
undercuts can be an issue. Heavy body impression material can compress the tissues resulting in 
excessive future adjustments.
Although border molding is recommended and extremely effective, some doctors may choose not to 
border mold, and instead use a technique that has proven successful for them in the past.
Addressing Undercuts
Typically, severe undercuts are not present in patient’s wearing a denture that is 10+ years old. 
Additionally, border molding with a heavy body impression material will help to relieve and insulate 
against under cuts.
With that said, If severe undercuts exist within the ridge of the denture, it is advisable to relieve  
the denture from the tissue using 3 small pieces of Celara Rapid Repair Tabs — acting as a tripod  
of tissue stops (Figure 6). This can be easily accomplished by softening the tab and placing 3 small 
pea-sized pieces on the tissue surfaces of the denture in three areas and having the patient bite 
lightly into occlusion. This technique will lift the denture(s) off the tissue slightly, approximately 
1mm per arch, assuring adequate thickness of impression material to enable the cast to come  
out of the undercut without breaking — providing the impression is properly boxed. When doing  
a two-stage impression technique, the heavy body material usually relieves the denture slightly.  
If severe undercuts exist, the denture base can be relieved with Rapid Repair Tabs prior to  
border molding.
Functional Impressions
When hyperplasia exists and it is necessary to heal the tissues prior to making the new denture, a 
tissue conditioning treatment regime can be used. When a functional impression technique is used 
as the final impression, and it becomes hard after being worn for several days, it is recommended 
a final wash of polyvinylsiloxane be made over the functional impression as a final wash. These 
functional impression materials can slump, resulting in an inaccurate impression, and the  
functional impressions can become hard and non-resilient, resulting in possible fracturing of the 
cast upon removal.
Occasionally, the hyperplasia occurs from the occlusion and must be treated after the new dentures 
are fabricated.
6
Figure 6