Influence of Color and Diameter of Retraction Cords and Teflon Tape on the Accuracy of Tooth Preparations Digitized by Using Intraoral Scanners

ABSTRACT Purpose To assess the influence of the color and diameter of retraction cords or Teflon tape and intraoral scanner (IOS) technology/system on the accuracy of crown preparations digitized using three IOSs. Materials and Methods A typodont with a crown preparation with an equigingival finish line was digitized using a laboratory scanner (control). Three groups were created: i700, TRIOS 5, and Aoralscan3. Six subgroups were developed depending on the retraction method: no cord (NC subgroup), purple 00 cord (Knittrax 00; Pascal Dental) (00‐K subgroup), yellow‐black 00 cord (Ultrapack 00; Ultradent) (00‐U subgroup), yellow 02 cord (Knittrax 02) (02‐K subgroup), green 02 cord (Ultrapack 02) (02‐U subgroup), and Teflon tape (T subgroup) ( n = 10). The control scan was used as a reference to measure the root mean square (RMS) error discrepancies with each experimental scan on the preparation and margin areas. Two‐way ANOVA and pairwise multiple comparisons tests were used to analyze trueness. Levene and pairwise comparisons tests were used to analyze precision (α = 0.05). Results In the preparation area, trueness differences were found among groups ( p < 0.001) and subgroups ( p < 0.001), with a significant group×subgroup interaction ( p < 0.001). The i700 and Aoralscan3 and the 00‐U, 02‐U, and T subgroups had the best trueness. In the margin area, trueness discrepancies were found among groups ( p < 0.001) and subgroups ( p < 0.001). The Aoralscan3 and 02‐U and T subgroups demonstrated the best trueness. Finally, precision discrepancies were found only in the preparation area among groups ( p < 0.001) and subgroups ( p < 0.001). The i700 and Aoralscan 3 groups and 02‐U and T subgroups had the best precision. Conclusions The IOS and retraction technique tested influenced the trueness and precision of the single tooth preparation cast. Clinical Significance The color and diameter of the retraction cord or Teflon tape used as the first cord in the double cord technique for digitizing a crown preparation with equigingival finish line did impact the scanning accuracy of the IOSs tested. However, the scanning discrepancies measured are not clinically relevant.