46 posters,  2 topics,  169 authors,  85 institutions

ePostersLive® by SciGen® Technologies S.A. All rights reserved.

13
The quality of Traditional Fixed Prosthodontic Impressions Received at Commercial Laboratories

Primary tabs

Rate

No votes yet

Statistics

834 reads

An Assessment of FDP Impressions Received at Commercial Laboratories

Rau C.T.1, Ólafsson V.G.*2, Delgado A.J.3, Ritter A.V., Boushell L.W., Donovan T.E.4

1US Navy Dental Corps, 2Faculty of Odontology, University of Iceland, 3College of Dentistry, University of Florida, 4School of Dentistry, University of North Carolina at Chapel Hil

Objectives: Providing the dental laboratory with an accurate replication of the hard and soft tissues of a patient is critical. The aims of the study were (1) to evaluate and quantify clinically detectable errors commonly seen in impressions sent to commercial laboratories and (2) to evaluate factors influencing a critical error of the finish line.

Methods: Three calibrated examiners visited 4 commercial laboratories between October 2013 and September 2014. All impressions for conventional crowns and bridges that arrived on the days of the visits were examined with 2.5x magnification prior to any laboratory processing. A total of 1157 impressions were examined and assessed against criteria laid out in a custom-designed assessment form. Data relating to the following were documented: tray selection, impression technique, prosthesis ordered, general errors in the impressions, and finish line errors. Crosstabs contingency with Chi-Square statistics were used to associate factors with a critical error of the finish line.

Results: 86% of the examined impressions had at least one detectable error, and 55% had at least one critical error of the finish line. Frequencies of errors and associating factors are listed in Tables 1 and 2.

Conclusion: Marginal discrepancies made up the largest error category. Simplified impression techniques increase the risk of obtaining critical errors. An improvement in technique and reviewing of all impressions can be strongly recommended.

 

Introduction

The transfer of accurate records to the dental laboratory is a vital part of any prosthesis fabrication. Previous studies have reported an alarming number of errors in impressions for conventional fixed prostheses. The aims of the study were to evaluate errors in impressions sent to commercial laboratories, and to evaluate factors influencing a critical error of the finish line.

Methods and Material

Three calibrated examiners visited 4 local dental laboratories during a 12 month period. Calibration was performed by examining rejected impressions at dental student clinics to determine common standards. All impressions for conventional fixed dental prostheses that arrived on the days of the visits were examined with 2.5x magnification under ambient light after standard disinfection procedures but prior to any other laboratory processing. A total of 1157 impressions were examined and assessed against criteria laid out in a custom-designed assessment form. Data relating to the following were documented: impression technique, tray type, number of prepared units, type of prosthesis ordered, tray showing through the occlusal surfaces, pressure of the tray on the soft tissue,  preparation voids, the presence of blood or coagulant, tissue impinging on the finish line and voids/tears along the margin.

Crosstabs contingency with Chi-Square statistics were used to associate factors with a critical error of the finish line.

 

Conclusion

86% of the examined impressions had at least one detectable error. 55% of the noted errors were critical errors pertaining to the finish line. Inadequate gingival displacement and simplified impression techniques such as dual-arch impression trays increase the risk of obtaining critical errors. An improvement in gingival displacement and impression techniques and reviewing of all impressions can be strongly recommended.

 

 

 

 

 

 

 

 

 

 

Enter Poster ID (e.gGoNextPreviousCurrent