Effect of polyvinylsiloxane material and impression handling on the accuracy of digital models.

INTRODUCTION The objective of this study was to evaluate the accuracy and reliability of measurements on digital models obtained by scanning impressions 5, 10, and 15 days after they were made from 2 soft putty polyvinylsiloxane (PVS) materials. METHODS Thirty volunteers were selected for making impressions of their dentitions with alginate to create a plaster model and with PVS impression material to create a digital model by laser scanning. Three examiners made the plaster model measurements with digital calipers and repeated these measurements on the digital models made from the scanned PVS impressions. A total of 34 distances were evaluated. Paired t tests were used to evaluate intraexaminer error and the accuracy of the digital model measurements. Measurement reproducibility and reliability among examiners were tested. RESULTS Although statistically significant differences between measurements on plaster and digital models were found, these discrepancies were not clinically significant except for overbite. Both plaster and digital models had high intraclass correlation coefficient values. CONCLUSIONS Digital models acquired by laser scanning of 2 types of soft putty PVS material may be used with clinically acceptable accuracy, reliability, and reproducibility, even at a postscanning interval of 15 days.