Quality of impressions after use of the Magic FoamCord gingival retraction system--a clinical study of 269 abutment teeth.
OBJECTIVE
The aim of this study was to evaluate a new gingival retraction system relative to clinical success for fixed dental restorations under various clinical conditions.


METHODS
Two hundred sixty-nine abutment teeth were evaluated. The ability to displace gingiva was indirectly measured by the quality of the final impression. Preparation finish line with respect to the crest of the marginal gingiva (Level I through III) and type of preparation finish line (ie, shoulder or beveled) were recorded. The reproduction of the preparation finish line and an absence of bubbles or voids (Criteria I through III) were assesed. The results were compared with an established retraction system using one retraction cord.


RESULTS
Of the 269 impressions evaluated, 93.7% were clinically acceptable and showed complete reproduction of the preparation finish line; 17.5% showed small defects but the impressions were still rated clinically acceptable and categorized as Criteria II. Only 6.3% of the impressions were unacceptable and categorized as Criteria III. A significant influence on the quality of the impressions was found when the preparation finish line was more than 2 mm subgingivally for shoulder (P < .004) as well as beveled preparations (P < .004). Nearly twice as many impressions were rated Criteria III when using the Magic FoamCord (MFC) system compared to impressions done with the single cord retraction technique.


CONCLUSIONS
In cases of epigingival and subgingival (< 2 mm) preparation margins, MFC was a less traumatic alternative method of gingival retraction. However, when there were deep subgingival margins and a beveled preparation, the material was less effective than the single cord retraction technique.
Clinical Department of Prosthetic Dentistry, Innsbruck Medical University, Innsbruck, Austria. ulrike.beier@uki.at
Ulrike S
US
Beier
Robert
R
Kranewitter
Herbert
H
Dumfahrt
D003761:Dental Impression Technique / Q000295:instrumentation*; D005881:Gingiva; D006801:Humans; D003765:Models, Dental; D011446:Prospective Studies; D019231:Tooth Preparation, Prosthodontic