#43

Another aspect of evaluation of the dental laboratory's product concerns the borders of the denture base. As previously explained. most often the proper extensions of the base are not determined by the dentist, or example, by outlining the borders on the impression, but they are apparent to a skilled technician from a good impression. The determination in part involves appropriately sculpturing the border to take into account the various muscle attachments to the ridges. It also involves how far to extend the borders where those anatomical features do not constitute limitations. Therefore, assuming that practicing dentists require that the dentures they insert in patients cover the greatest possible area while permitting function, the laboratory must be aware of the maximum appropriate extensions and fabricate dentures accordingly in order two satisfy its customers, and must have knowledge of various anatomical features of the mouth in order to determine an evaluate these aspects of its product.

The need to avoid remaking its work to maintain the profitability of its business further requires the ability to evaluate certain aspects of the dentist's work at interim states of the denture care process. Denture bases are constructed from casts made from impressions of the mouth. If the impressions do not record the various landmarks of the mouth in adequate detail or if the contours of the mouth are distorted, the appropriate borders of the base cannot be determined and the base will not closely conform to the mouth and so will be uncomfortable. Therefore in order to initially produce a product which will ultimately be satisfactory, the laboratory must be able to determine whether or not it has received satisfactory impressions from the dentist. While the laboratory need not know how to produce good impressions, it must have knowledge to evaluate the outcome.