Quintessence Int 41 (2010), No. 10 6. Oct. 2010
Quintessence Int 41 (2010), No. 10 (06.10.2010)
Page 845-853, PubMed:20927421
Comparison of the three-dimensional correctness of impression techniques: A randomized controlled trial
Luthardt, Ralph Gunnar / Walter, Michael H. / Quaas, Sebastian / Koch, Rainer / Rudolph, Heike
Objective: In vitro studies showed superior impression correctness for one-stage impressions. However, clinical data, especially clinical trials, are lacking in this matter. The aim of the study was to investigate the three-dimensional correctness of impressions for final restorations applying three different impression techniques.
Method and Materials: Three impressions each were made from 48 patients with different techniques using metal stock trays. In a randomized order, one-stage putty-wash, two-stage putty-wash, and monophase impressions (respectively, Dimension Penta H and Garant L, Dimension Penta H Quick and Garant L Quick, Impregum Penta; 3M ESPE) were made with either polyvinyl siloxane or polyether materials. The double-cord technique was applied at all abutment teeth. Factors potentially influencing the correctness of the impressions were recorded. The precision of the impressions was three-dimensionally analyzed using the resulting gypsum models. Discrepancies between the impressions were calculated using the one-stage putty-wash impression as reference.
Results: Discrepancies between the one-stage puttywash impressions and the monophase impressions are significantly lower compared with two-stage putty-wash impressions. The depth of the most subgingival portion of the preparation margin significantly influences the discrepancies between the impression techniques.
Conclusion: In light of the major influence of clinical parameters on impression correctness, one-stage procedures should be favored. These findings support the results of in vitro investigations.
Keywords: crown, fixed partial denture, impression, monophase, one-stage putty wash, randomized controlled trial, three-dimensional precision, two-stage putty wash