Clinical comparison of two Impression Materials- Effectiveness for inexperienced operators

Objectives: This prospective randomized clinical trial compared a new polyvinyl siloxane (PVS) impression material (Imprint 3 Light Body, 3M ESPE, St. Paul, MN) to another commercially available PVS impression material (Aquasil Ultra LV, LD Caulk, Milford, DE) by evaluating the ability of inexperienced clinicians (pre-doctoral dental students) to obtain accurate final impressions for indirect fixed full-coverage restorations.

Materials and methods:

110 patients were enrolled in the study after receiving informed consent at the University of Alabama in Birmingham/ School of Dentistry. Those meeting the inclusion criteria were randomly assigned to one of two treatment groups Group A or Group B. Calibrated examiners evaluated the first impression of prepared posterior teeth at a magnification of x10 for acceptability (no voids or bubbles) according to the data collection sheet. Criteria evaluated and recorded were: position of tooth, type of preparation, preparation finish line (Class I-V), and gingival bleeding score. For subjects assigned to Group A, impressions were made with a PVS Imprint 3 while those in group B received Aquasil Ultra LV impression material. All impressions were made using a heavy tray material and a light body syringe material. For this interim report, 110 of a planned 300 impressions are completed.

Results:

54 Imprint 3 vs 56 Aquasil Ultra data collection sheets were recorded and analyzed using the Chi-Square test. Imprint 3 produced clinically better first impressions compared to Aquasil Ultra LV (p=.043). Thirty unacceptable impressions were made; 10 were Imprint 3 Light Body and 20 were Aquasil Ultra LV.

Conclusion: further analysis will be completed at the end of the study, and final conclusions will be drawn accordingly. However, with the current data we can say that the Imprint 3 produced more clinically acceptable impressions with inexperienced operators.