Comparison of the three-dimensional correctness of impression techniques: A randomized controlled trial

• Autores: Ralph G. Luthardt, Michael H. Walter, Sebastian Quaas, Rainer Koch, Heike Rudolph
• Localización: Quintessence International, ISSN-e 0033-6572, Vol. 41, Nº. 10, 2010, págs. 845-853
• Idioma: inglés
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• Resumen

  • 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.