Influence of Gingival Color and Finish Line Location on the Accuracy of Intraoral Scans for Complete-Arch Tooth Preparation.

Purpose: To investigate the influence of different gingival colors and finish line locations on the accuracy of intraoral scans for complete-arch tooth preparation.

Methods: Ten complete-arch maxillary models with 5 different gingival colors [light pink (LP), dark pink (DP), orange (Or), brown (Br), and purple (P)] and 2 different finish line locations [equigingival (Eq) and subgingival (Sb)] were used. Ten scans of each reference model were made with an intraoral scanner and exported as STL files. Assessment of precision and trueness was conducted with 3D analysis software. Each STL file was individually aligned with the reference scan and 3D differences were calculated using the root mean square (RMS) value. Data were statistically analyzed using 2-way ANOVA and Tukey HSD tests (α=.05).

Results: Regarding trueness, significant differences were found between different gingival colors and finish line locations. The highest mean RMS value was found in the gingival color group of Or with Sb finish line. Regardless of the finish line location applied, significantly lower RMS values were found in the gingival color groups of Br and P. Regarding precision, finish line location significantly influenced the mean RMS values of LP, DP, and Or. Regardless of the finish line location applied, significantly lower RMS values were obtained in the gingival color groups of Br and P.

Conclusions: Gingival color influenced the scan accuracy of complete-arch tooth preparation. When the gingival color was a darker gingival color, the scan accuracy was improved, especially in the case of a subgingival finish line location.