A Three-Dimensional Analysis of the Influence of Palatal Vault Depth on Digitization Accuracy of Partially Dentate Arches.

Purpose: To evaluate the impact of palatal vault depth on the accuracy of scans obtained using three digitization techniques for partially dentate arches through three-dimensional (3D) analysis.

Materials and methods: Four maxillary Kennedy class II resin casts with varying palatal vault depths (flat: 20.4°, shallow: 26.1°, medium: 40.7°, deep: 58.8°) were digitized using three techniques: direct (intraoral scanner), indirect impression digitization, and indirect cast digitization. Each cast was scanned five times per technique, producing 60 scans. The scanned files were analyzed for trueness and precision using a digital metrology program, with root mean square (RMS) deviations assessed via color maps. Data were analyzed using two way ANOVA and Tukey HSD test (α = .05).

Results: Direct digitization showed larger palatal deviations compared to indirect methods. The deep vault exhibited the lowest trueness (53.3 ± 7.4 µm) and precision (50.7 ± 6.6 µm) when digitized directly (P < .001). Indirect impression digitization produced the lowest trueness (35.8 ± 7.2 µm) and precision (31.5 ± 3.1 µm) for the medium vault. Indirect cast digitization had the lowest trueness (23.1 ± 3.4 µm) for the medium vault and the lowest precision (31.3 ± 3.2 µm) for the deep vault (P < .001).

Conclusion: Digitization accuracy (trueness and precision) was significantly influenced by vault depth and the interaction between digitization technique and depth (P < .001). Direct digitization had the highest accuracy for the medium vault, whereas indirect techniques provided superior accuracy for other vault depths. The deep vault showed reduced accuracy with both direct and indirect digitization methods.