Casting and Impression Standards
It is essential that the appliance fit in the mouth precisely. Thus, the cast and impression must be completely accurate. Start with the first (and most critical) stage in fabricating your appliance – the cast.
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Casts should be trimmed perpendicular to the long axis of the incisors and trimmed no higher than 3/4". It is essential when constructing a full arch appliance that the palate be trimmed away in order that the vacuum reach the lingual surfaces. Using high quality die stone is recommended due to its strength and low expansion rates. | Our appliances are constructed with the discipline associated with crown and bridge technology, i.e., sturdy trays, quality impression materials, die stone and efficient thermoforming technology. |
Of course, the cast can only be as accurate as the impression. Due to the appliance's reliance on retentive undercuts for its fit, the impression must register these undercuts precisely. | |
| Quality impression material Polyvinyl siloxane is preferred. It has excellent elastic recovery, minimal permanent deformation and superior tear strength. Impressions can be stored and repoured up to 6 months later without any significant loss of accuracy. | |
We recommend PVS impression materials, such at Affinis ®. Although slightly more expensive, the cost is more than compensated by fewer remakes and a better fitting appliance. | |
