A Clinical Evaluation of Fixed Partial Denture Impressions
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December 1, 2005
Volume 1, Issue 2, Nov/Dec 2005
Page(s):
Samet N, Shohat M, Livny A, Weiss EI. J Prosthet Dent. 2005 Aug; 94(2):112-7.
This study provides all of us with staggering data: of 193 impressions for FPDs from 11 dental laboratories, 172 (i.e., 89.1%) had 1 or more detectable errors. From the design of this research study, the types of errors documented are those that can be easily visualized and evaluated by the clinician making the impression. Of the criteria of errors that were reported, the nature of what dentists are willing to send to the dental laboratory for the fabrication of FPDs are impressions that demonstrated voids and tears at the finish lines (50.7%); putty exposure through wash (double-step technique) (44.0%); air bubbles at the finish line (40.4%); pressure of the tray on soft tissue (38.3%); inadequate retention of the material to the tray (33.7%); flow problems (23.8%); and retraction cord attached to the impression (6.2%). These inaccuracies lead to unacceptable restorations.
The authors picked impressions that were made for the fabrication of FPDs. A licensed dentist that a patient trusted with his or her treatment sent in inadequate, inaccurate, and unacceptable impressions for the fabrication and, it is assumed, the ultimate cementation of questionable restorations. Making accurate impressions should not be a coin toss, but an exacting, most important procedure.
What is also frightening is the fact that laboratories used these deficient impressions and fabricated questionable restorations, returning them to dentists who had minimal complaints regarding the accuracy of fit. The dental laboratory is in a quandary; do they return the unacceptable impressions and then lose the business of that dentist, or do they keep their mouths shut and let it all fly by?
We need to be responsible for the treatment we provide our patients. The conclusion of this article summarized the clinical implications of the study results. More critical evaluation of impressions for fixed prosthodontics on the part of the dentist is recommended.
Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School, Baltimore, Maryland
Email: hstrassler@umaryland.edu
