About the Author: Howard Cosner, Jr., CDT, is a 52-year veteran of the profession. Certified for 40 years, he was designated "Technologist" by the NBC in 2006. With an Active-Retired NBC status, he operates a small dental materials R&D and advanced dental prosthetics learning service in the Orlando, FL area. He has published numerous articles and during his career, he was also a dental materials R&D specialist, technician and engineering technician with the U.S. Army Institute of Dental Research, Division of Dental Materials, Walter Reed, AMC, in Washington DC.
An occlusal/palatal view of the completed RPD showing the basic reciprocal structuring of the design. The lingual fit is passive with all undercuts blocked out.
The completed unilateral acrylic RPD showing the tooth-colored clasps. There is no retention used at the junction of the acrylic base material; this is blocked out during processing.
The model with the actual survey lines as a guide to the acrylic clasp location. All undesirable undercuts were blocked out, with the exception of the retentive tips, which were blocked out to reflect .01 retention. Processing this restoration on an accurate, duplicate model allowed the structural and dimensional integrity of the acrylic resin to ensure an accurate fit. No adjustments to the clasps were necessary.